project name - scottish government...project name scottish trunk road network south east unit...

Project Name Scottish Trunk Road Network South East Unit Document Title A702/A703 Hillend Study

Doc. Ref.:18/SE/0801/019 /001 - i - Issued: February 2020

Executive Summary

The A702/A703 Junction at Hillend is located 1km south of the A720 Lothianburn Junction and connects the

A702, A703 and Old Pentland Road. The A702 starts from the A720 Lothianburn Junction, Edinburgh and

continues to the M74 J13, Abington.

This junction has been highlighted in the Moving Cursor Programme and has been investigated further at the

request of Transport Scotland. Between January 2014 and December 2018 inclusive, seven personal injury

accidents occurred at this junction. Four of these collisions occurred due to manoeuvres involving the junction.

Previous remedial works were undertaken in 2012 that removed the slip lane leading to the A703. The aim

of this was to reduce the speed of turning traffic. Following these remedial works there was a reduction in

collisions recorded in a five-year period. However, based on recorded collision frequency and causation since

then, a problem still exists.

A conflict study to assess driver behaviour at this junction was carried out in March 2019. The study was

based upon methods set out in the Royal Society for the Prevention of Accidents (RoSPA) Road Safety

Engineering Manual. Over the four-day period, over 5,500 conflicts were recorded. Per day of the conflict

study, on average 8% of road users were implicated in a conflict. The number of conflicts recorded for each

severity classification is shown below:

Severity No. of Conflicts

0 5220

1 326

2 93

3 57

4 0

5 0


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A list of remedial measures has been identified to improve the road safety of the junction to better align with

the Strategic Road Safety Plan (SRSP). Measure descriptions and estimated cost ranges for each option are

shown below:

Option Measure Estimated Cost

1A TRO - Prohibiting left turns exiting minor roads. £15,000 - £30,000

1B TRO - One-Way System (Junction in – A703 / Junction out – Old Pentland

Road). £15,000 - £30,000

1C TRO - Prohibition of right turn from A702 on to minor roads. £15,000 - £30,000

2A Realignment of A703. Closure of Old Pentland Road junction. New signalised

junction to be constructed in vicinity of existing junction. £4 – £6 million

2B

Closure of existing A703 junction, realignment and signalisation of new A703

junction south of existing. Old Pentland Road to remain as existing with addition

of right turn ghost island.

£3 - £5 million

3A

Connection of Old Pentland Road to A703 and construction of roundabout in

the vicinity of existing junction. Realignment of A702 south of proposed

roundabout.

£8 – £11 million

3B

Closure of existing A703 junction, realignment and roundabout construction

using the new A703 alignment. Old Pentland Road to remain as existing with

addition of right turn ghost island.

£6 – £8 million

Only the A702 is part of the South East Trunk Road Unit, with Midlothian Council being responsible for both

minor roads. Therefore, liaison with Midlothian Council will be required regarding all remedial options

suggested to ensure a collaborative solution is agreed upon.

Remedial measures reviewed as an outcome of the area assessment and site investigations are in

accordance with the two SRSP Actions, shown below:

Action No. Action Description

1 Trunk Road Analysis & Collision Screening

3 In depth analysis of fatal and serious collisions


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Contents

1 Introduction ............................................................................................................ 1

1.1 Overview ............................................................................................................... 1

1.2 Background ............................................................................................................ 1

2 Site Description ....................................................................................................... 3

2.1 General Description ................................................................................................ 3

2.2 Traffic Flows .......................................................................................................... 5

2.3 Previous Investigations ......................................................................................... 12

3 Collision Analysis ................................................................................................... 13

3.1 Ten-Year Collision Overview .................................................................................. 13

3.2 Previous Improvement Works Influence on Collisions .............................................. 13

3.3 Ten-Year Poisson’s Distribution ............................................................................. 14

3.4 Five-Year Collision Analysis ................................................................................... 14

3.5 Annual Accident Rate (AAR) Comparison ................................................................ 16

4 Site Investigation .................................................................................................. 18

4.1 Junction Layout .................................................................................................... 18

4.2 Visibility ............................................................................................................... 19

4.3 Road Surface Condition Review ............................................................................. 21

4.4 Road Signs and Markings ...................................................................................... 23

4.5 Bend Assessment ................................................................................................. 26

4.6 Drainage .............................................................................................................. 27

4.7 Non-Motorised Users Provision .............................................................................. 29

4.8 Street Lighting ..................................................................................................... 33

4.9 Swept Path Analysis .............................................................................................. 35

4.10 Future Developments ............................................................................................ 38

5 Site Observations .................................................................................................. 39

5.1 Overview ............................................................................................................. 39

5.2 Driver Behaviour .................................................................................................. 39

6 Conflict Study ........................................................................................................ 44

6.1 Background .......................................................................................................... 44

6.2 Survey Methodology ............................................................................................. 44

6.3 Peak Hours .......................................................................................................... 46

6.4 Vehicle Speed ...................................................................................................... 47

7 Remedial Options .................................................................................................. 50

7.1 Overview ............................................................................................................. 50

7.2 Remedial Measures ............................................................................................... 50


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8 Conclusions and Recommendations ...................................................................... 58

Appendix A Collision Stick Diagrams 1

Appendix B Design Speed Calculations for A702 B.1

Appendix C Camera Locations for Conflict Study C.1

Appendix D Remedial Options D.1

Appendix E Roundabout Capacity Calculations E.1


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Figures

Figure 1-1 – Location plan of junctions under investigation ................................................................... 1

Figure 2-1 – Layout of junctions under investigation ............................................................................. 3

Figure 2-2 – A702 Hillend speed limit traffic conditions ......................................................................... 4

Figure 2-3 – Traffic counter locations................................................................................................... 5

Figure 2-4 – A702 North of Hillend AADF 2005-2018 (ATC05080) .......................................................... 6

Figure 2-5 – A702 South of Hillend AADF 2007-2018 (135650) .............................................................. 6

Figure 2-6 – A703 AADF 2000-2017 (50963) ........................................................................................ 7

Figure 2-7 – A702 Hillend traffic classification breakdown ..................................................................... 8

Figure 2-8 – A703 traffic classification breakdown ................................................................................ 8

Figure 2-9 – Vehicle movement at junction .......................................................................................... 9

Figure 2-10 – Comparison between traffic counter data and conflict study count data .......................... 11

Figure 2-11 – A702/A703 Hillend Junction layout pre-2012 improvements ........................................... 12

Figure 3-1 – Ten-year collision profile ................................................................................................ 13

Figure 3-2 – A702 A703 Hillend poisson analysis of 10 years collision data ........................................... 14

Figure 3-3 – Collision locations (Jan 2014 to Dec 2018) ...................................................................... 15

Figure 4-1 – Junction layout taken from Old Pentland Road footpath facing south ................................ 18

Figure 4-2 – Level of provision for junctions on single carriageway roads from DMRB CD 123 ............... 19

Figure 4-3 – Design geometric parameters ......................................................................................... 20

Figure 4-4 – Worn high friction surface on the A703 ........................................................................... 21

Figure 4-5 – A702 Hillend SCRIM summary ........................................................................................ 22

Figure 4-6 – A702 Hillend rutting summary ........................................................................................ 23

Figure 4-7 – A702 Hillend texture depth summary .............................................................................. 23

Figure 4-8 – Bend categories from APG E115 ..................................................................................... 26

Figure 4-9 – Top entry gully, A702 Hillend ......................................................................................... 28

Figure 4-10 – A702/A703 Hillend top entry gully locations ................................................................... 28

Figure 4-11 – A702 Footway provision at A702/A703 Junction ............................................................. 29

Figure 4-12 – (a) Footpath overgrown with vegetation (b) Narrow footpath ......................................... 30

Figure 4-13 – Vegetation at pedestrian crossing ................................................................................. 31

Figure 4-14 – Old Pentland Road tactile paving and drop kerb ............................................................ 31

Figure 4-15 – A702/A703 Hillend bus stop locations ........................................................................... 32

Figure 4-16 – Capital view walking route (Walkhighlands) ................................................................... 33

Figure 4-17 – Street Lighting Provision at A702/A703 Hillend Junction ................................................. 34

Figure 4-18 – Lighting Columns, A702/A703 Junction ......................................................................... 34

Figure 4-19 – Swept path analysis for private car turning left from A703 junction ................................. 35

Figure 4-20 – Road user turning left from A703: (a) beginning to turn (b) encroaching NB carriageway

(c) same as previous (d) beginning to recover lane boundary ........................................... 36


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Figure 4-21 – Swept path analysis for private car turning left from Old Pentland Road junction A703

.................................................................................................................................... 37

Figure 4-22 – Road user turning left from Old Pentland Road conflict study encroaching nearside red

hatching ....................................................................................................................... 37

Figure 5-1 – Vehicle turning from the A702 SB to the A703 crossing the red hatching during: (a) site

visit (b) video survey ..................................................................................................... 39

Figure 5-2 – Road user stopping short of Old Pentland Road stop line ................................................. 40

Figure 5-3 – A702 SB to Old Pentland Road: (a) prior to turning, sharp radii produced by hatching

(b) mid turn, narrow carriageway ahead ......................................................................... 40

Figure 5-4 – A702 NB to Old Pentland Road: (a) prior to turning, large turning angle required (b)

post turn, oncoming traffic and narrow carriageway ........................................................ 41

Figure 5-5 – Old Pentland Road vehicle using opposing traffic lane ...................................................... 41

Figure 5-6 – Visibility difficulties at the A702/A703 junction ................................................................ 42

Figure 5-7 – Old Pentland Road to A702 SB, vehicle crossing nearside hatching: (a) begins to turn

as Amey vehicle turns into A702 (b) continues to turn ..................................................... 43

Figure 6-1 – Traffic counter locations................................................................................................. 47

Figure 6-2 – 85th percentile speed at ATC1 southbound ...................................................................... 48

Figure 6-3 – 85th percentile speed at ATC2 northbound ...................................................................... 49

Tables

Table 1-1 – Strategic Road Safety Plan actions considered .................................................................... 2

Table 2-1 – Cyclists compared with traffic counts ............................................................................... 10

Table 3-1 – Collision summary .......................................................................................................... 15

Table 3-2 – Annual Accident Rate (AAR) comparison .......................................................................... 17

Table 4-1 – A702 A703 Hillend junction signs and markings ................................................................ 24

Table 4-2 – APG_E115 Bend assessment results ................................................................................. 27

Table 4-3 – Pedestrian crossing count results ..................................................................................... 30

Table 6-1 – Conflict descriptions ........................................................................................................ 45

Table 6-2 – RoSPA conflict severities ................................................................................................. 45

Table 6-3 – Breakdown of severity .................................................................................................... 46

Table 6-4 – Conflicts compared with traffic count ............................................................................... 47

Table 6-5 – Vehicle speed ................................................................................................................. 48

Table 7-1 – Reviewed remedial measures .......................................................................................... 52

Table 8-1 – Remedial measures and costs ......................................................................................... 59


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1 Introduction

1.1 Overview

1.1.1 The A702/A703 Junction at Hillend is situated 1km south of the A720 Lothianburn Junction and

connects the A702, A703 and Old Pentland Road. The A702 starts from the A720 Lothianburn

Junction, Edinburgh and continues to the M74 J13, Abington.

1.1.2 The A703 connects the A702 to the A701 near Pentland Science Park. Old Pentland Road links

the A702 to the A701 at Pentland Industrial Estate. Figure 1-1 below shows a location plan of the

junction under investigation.

Figure 1-1 – Location plan of junctions under investigation

1.2 Background

1.2.1 This study has been undertaken by Amey due to the junction being identified as part of the

Moving Cursor Programme (MCP). The MCP is an annual programme which analyses accident

rates, stakeholder concerns and collision cluster sites within the South East Trunk Road Unit. A

cluster is denoted when more than three collisions occur within a hundred metre radius. The MCP

facilitates determination of sites that require further investigation. The A702/A703 Hillend junction



under review was highlighted in the 2018/19 MCP as a cluster site and in 2016/17 and 2017/18

as a location highlighted as an area of concern by Midlothian Council, the relevant stakeholder.

1.2.2 Location, causation and contributory factors of collisions and the current junction geometry have

been reviewed and a subsequent conflict study has been undertaken focusing on vehicle

movements. Where appropriate, recommendations have been made to improve safety at this

location, aiming to reduce future collisions, risks and casualty severity.

1.2.3 Consideration is given to the Safe System approach, aligning with Transport Scotland’s Strategic

Road Safety Plan (SRSP), which details actions that concentrate on the continual development of

the safety of Scottish trunk roads. The Safe Systems approach focuses on preventing serious or

fatal harm as opposed to full eradication of all collisions by acknowledging that some form of

human error will lead to collisions occurring. Actions from the SRSP considered within this report

are shown in Table 1-1.

Table 1-1 – Strategic Road Safety Plan actions considered

Action

No. Action Description Mitigation Measures to meet action

1 Trunk Road Analysis &

Collision Screening

The site was identified in the MCP as a cluster site due to the

number of collisions that occurred in 2018/19 and as an area

of concern within the 2016/17 and 2017/18 reports. The

junction had been assessed previously due to the historic

concerns, but no long-term remedial measures were

concluded post 2012 remedial measures implemented.

Monitoring of the junction was recommended. The recent

recognition of the junction in the 2018/19 MCP shows further

investigation is required.

3 In depth analysis of

fatal and serious

collisions

The collisions that occurred during the study period have

been thoroughly investigated and analysed to identify

causation factors and common trends.



2 Site Description

2.1 General Description

2.1.1 The junction consists of two neighbouring junctions, one connecting the A702 and Old Pentland

Road and the other connecting the A702 and the A703, shown in Figure 2-1. Both the A703 and

Old Pentland Road are minor roads that are maintained by Midlothian Council. The A702 is the

major road in this instance, which is part of the South East Trunk Road Unit.

Figure 2-1 – Layout of junctions under investigation

2.1.2 All roads at this junction are subject to a 40-mph sign posted speed limit. The boundaries between

40-mph speed limit and national speed limit (NSL) areas are displayed in Figure 2-2.

2.1.3 Since minor roads are not part of the South East Trunk Road Unit, analysis and investigation of

both roads is restricted. During site visits, approximately 50m of each road from the junction with

the A702 was investigated.

Old Pentland Road

Junction (Minor road)

A703 Junction

(Minor road)

A702

(Trunk road)



Figure 2-2 – A702 Hillend speed limit traffic conditions

A702

A703

(Minor road)

Old Pentland Road

(Minor road)

A702/A703

Hillend Junction

40 mph

NSL

40 mph

NSL

NSL



2.2 Traffic Flows

Traffic Counter Flows

2.2.1 Figure 2-3 displays traffic counters in the vicinity of the A702/A703 junction as well as the most

recent Annual Average Daily Flows (AADF) recorded. Data concerning the A702 trunk road has

been collected from Traffic Scotland. Since there is only trunk road information through Traffic

Scotland, counter data from Department for Transport was utilised to allow analysis of the A703

as well. No counter data was available for Old Pentland Road.

Figure 2-3 – Traffic counter locations

2.2.2 Traffic Scotland Data Counter Point (ATC05080) is situated on the A702, north of the junction.

AADF were obtained between 2005 and 2018, presented in Figure 2-4. The trendline for this data

shows an overall increasing AADF, indicating rising traffic flow through this junction. The AADF

count for 2018 is 21,350.

A702/A703

Junction

ATC05080

AADF 21,350

50963

AADF 5,883

135650

AADF 10,591



Figure 2-4 – A702 North of Hillend AADF 2005-2018 (ATC05080)

2.2.3 Traffic Scotland Traffic Data Counter Point (135650) is situated around 800m south of the junction

on the A702, as shown in Figure 2-3. Count data for this was obtained from 2007 to 2018, as

shown in Figure 2-5. The trendline for this data also shows an increasing AADF. The current AADF

count for 2018 is 10,591.

Figure 2-5 – A702 South of Hillend AADF 2007-2018 (135650)

2.2.4 Count data from north and south of the junction indicate that approximately 10,700 vehicles enter

or exit the A702 at Hillend junction daily.

2.2.5 Department for Transport Data Counter Point (50963) is situated around 1.5km south of the

junction on the A703, also shown in Figure 2-3. AADF values were obtained from the traffic count

point for the years 2000 to 2017, presented in Figure 2-6. Unlike the A702 traffic count, this data

shows an overall decreasing AADF. The latest estimated count for this point is 5,883 AADF.

19,000

19,500

20,000

20,500

21,000

21,500

22,000

22,500

2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018

AAD

F

Year

9,000

9,500

10,000

10,500

11,000

11,500

12,000

12,500

2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018

AAD

F

Year



Figure 2-6 – A703 AADF 2000-2017 (50963)

2.2.6 Data obtained for Traffic Data Counter 50963 only had two years of results obtained using actual

counts (2006 and 2013), with the remainder predicted using estimates from the previous year’s

AADT on this link. As a result, there may be inaccuracies in this data.

2.2.7 Traffic count data for the A702 and A703 indicate that 4,800 vehicles are using the Old Pentland

Road junction daily.

2.2.8 The numbers of different vehicle classes on the A702 were obtained from the Department of

Transport Traffic Data Counter Point (Counter 80164). This data is presented in Figure 2-7. Most

vehicles passing this traffic counter are cars/taxis (79.40%), followed by Buses and LGV (13.43%)

and HGVs (5.96%).

5000

5500

6000

6500

7000

7500

8000

8500

9000

2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017

AAD

F

Year



Figure 2-7 – A702 Hillend traffic classification breakdown

2.2.9 The percentages of different vehicle classes passing the counter point on the A703 (Counter

50963) are presented in Figure 2-8. This shows a similar breakdown of vehicle classifications as

the A702 traffic count point, with cars accounting for 75.8%.

Figure 2-8 – A703 traffic classification breakdown

111 155

17542

202

2765

1317

0

2000

4000

6000

8000

10000

12000

14000

16000

18000

20000

Pedal Cycles Motorcycles Cars/Taxis Buses/Coaches Light GoodsVehicles

All HGVs

AAD

F V

olu

me

Type of Vehicle

35 58

4485

53

962

326

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

Pedal Cycles Motorcycles Cars/Taxis Buses/Coaches Light GoodsVehicles

All HGVs

AA

DF

Vo

lum

e

Type of Vehicle



Conflict Study Traffic Flows

2.2.10 A conflict study was carried out as part of this report, to be discussed in detail in Section 6. As

part of this study, traffic counts were obtained over a seven-day period.

2.2.11 The number of vehicles that passed through the junction during the survey period were recorded.

Ten individual manoeuvres were recognised, shown in Figure 2-9, alongside average weekday

(Monday – Friday) traffic movement volumes recorded.

Figure 2-9 – Vehicle movement at junction

2.2.12 The most popular movement noted was vehicles travelling northbound or southbound along the

A702 (Movements 5 & 8), which equated to 56.0% of the total weekday average daily flow (ADF).

2.2.13 Traffic using the A703 junction equated to 31.4% of the weekday ADF. However, most of the

traffic flow at this junction was entering or exiting northbound (Movements 2 & 10). Cars entering

or exiting southbound, performing either a left-turn from the A703 to A702 southbound or turning



right from the A702 northbound to the A703 (Movements 1 & 6) only equated to 9% of the flow

related to the A703.

2.2.14 Old Pentland Road traffic was calculated to attribute to 12.6% of the weekday ADF. Again, road

users favoured travelling northbound to or from the junction (Movements 4 & 9). This equated

to 91% of traffic using Old Pentland Road.

2.2.15 Average flow of HGVs for weekdays varied between 0.3% (Movement 3) and 7% (Movement 8)

dependent on the movement carried out.

2.2.16 Throughout the four-day conflict analysis period, a total of 508 cyclists were recorded. Table 2-1

shows the number of cyclists as a percentage of traffic flow for the study area including all

movements. The number of cyclists within the area of investigation is low.

Table 2-1 – Cyclists compared with traffic counts

Day Traffic Count Total Cyclists

Cyclists

(%)

Saturday 23rd March 17578 146 0.83

Sunday 24th March 15951 81 0.51

Monday 25th March 22262 144 0.65

Tuesday 26th March 21942 137 0.62

2.2.17 No SUSTRANS cycle routes are within the vicinity of the junction.

Comparison in Traffic Flow Data

2.2.18 Although the data collecting period for the conflict study differs from that of the traffic counter

AADF values, a comparison between the average daily flow found during the conflict study and

traffic counter values was carried out, shown in Figure 2-10. A comparison of vehicle breakdown

with traffic counter data has not been undertaken due to a different breakdown in vehicle types.

2.2.19 An estimated AADF for Old Pentland Road was calculated in Section 2.2.7 This has been used to

allow a comparison between conflict study and traffic counter data.



Figure 2-10 – Comparison between traffic counter data and conflict study count data

2.2.20 Data categorised as ‘NB’ within Figure 2-10 compared A702 northbound traffic flows from the

conflict study and the north traffic counter, ATC05080. ‘SB’ data compares A702 southbound

traffic from the study and counter point 135650. Comparing the data, there is not a huge deviation

in conflict study and traffic counter counts. A maximum difference of 3.6% is found comparing

northbound data. However, the differences could be attributed to the fact that the traffic counters

are located further from the junction, so consider a greater area of flow.

2.2.21 Old Pentland Road was found to have the greatest deviation between results. However, since

there is no actual traffic counter on this minor road and only an estimation was used, as discussed

in Section 2.2.20, it can be assumed that unreliability in the estimation is the main factor for the

large deviation recorded.

2.2.22 Based on data from traffic counters and conflict study, the largest AADF was found north of the

junction, close to the A720, and the lowest on Old Pentland Road. This shows that both sets of

data exhibit the same pattern.

0

5000

10000

15000

20000

25000

OPR A703 NB SB

Traffic Counter

Conlfict Study Counts



2.3 Previous Investigations

2.3.1 Improvement works were undertaken at this junction in 2012 under the 3rd Generation (3G)

Operation & Maintenance (O&M) Contract.

2.3.2 This junction was first highlighted in the 2009-10 Moving Cursor Programme and was

subsequently investigated by BEAR Scotland.

2.3.3 As shown in Figure 2-11, the junction previously featured two lanes on the southbound

carriageway, with the near side lane acting as a slip lane for the A703. This layout made for high

speeds through the junction as drivers on the A702 had no need to reduce their speed to exit on

to the A703 or Old Pentland Road, making it difficult for drivers exiting the minor roads to find a

suitable gap for joining the main line.

Figure 2-11 – A702/A703 Hillend Junction layout pre-2012 improvements

2.3.4 The results of this investigation were that the southbound carriageway of the A702 be reduced

to one lane to increase the traffic calming effects of drivers slowing as they approach the junction.

Additionally, it was recommended that much of the signage clutter was removed and road verge

vegetation trimmed back. These improvements were implemented in 2012.

Old Pentland Road

A703

A702



3 Collision Analysis

3.1 Ten-Year Collision Overview

3.1.1 A review of the recorded collisions from January 2009 to December 2018 has been carried out to

identify any significant changes in collision data at the investigation site, shown in Figure 3-1.

Collision data analysis is focused on the A702 trunk road traffic due to the data available. There

was a total of 18 casualty collisions (one serious and seventeen slight) over the ten-year period,

equalling an average of 1.8 collisions per year.

Figure 3-1 – Ten-year collision profile

3.1.2 Collision data shows a decrease in fatal and serious accidents. Only one serious collision was

recorded in 2013.

3.2 Previous Improvement Works Influence on Collisions

3.2.1 Remedial measures were implemented at this junction in 2012, as discussed in Section 2.3. Since

remedial measures, collisions recorded has fluctuated. Overall, there is a decreasing trend

apparent.

3.2.2 In the five years leading up to the improvement works (2007-2011), there was a total of eleven

collisions at this junction. Ten of which were slight in severity, with one serious collision recorded

in 2007.

0

1

2

3

4

5

6

2009 2010 2011 2012 2013 2014 2015 2016 2017 2018

Num

ber

of

colli

sions

Year

Fatal

Serious

Slight

Average number

of collisions = 1.8

collisions/year



3.2.3 In the five years following the (2013-2017), there was a total of five collisions related to the

junctions – four slight and one serious.

3.2.4 Per year, the number of collisions on average has decreased since improvement works were

implemented. However, the frequency and nature of collisions that have occurred since still

indicate that there is an issue at the junction. Although full eradication is not possible, as set out

in the Safe Systems Approach discussed in Section 1, measures should be implemented that

prevent serious and fatal injuries. Historic collision data shows that even after improvement works

in 2012, a serious collision has occurred and therefore further remedial measures should be

considered.

3.3 Ten-Year Poisson’s Distribution

3.3.1 Considering Poisson’s Distribution, only 2010 was recorded to have results with a high confidence

over the average. All other years did not have a significant increase above or decrease below

average results. Results are shown in Figure 3-2.

Figure 3-2 – A702 A703 Hillend poisson analysis of 10 years collision data

3.4 Five-Year Collision Analysis

3.4.1 Collision data recorded between January 2014 and December 2018 has been found using

Transport Scotland’s Integrated Road Information System (IRIS) database and analysed for the

study section. Again, only data relating to the A702 trunk road has been analysed. Within this

five-year period, seven collisions were recorded, four of which relate to the junction. Collision

locations are shown in Figure 3-3, with summarised collision details in Table 3-1.

3.4.2 Detailed stick diagrams for each collision are located in Appendix A.

1% V high Confidence

5% High Confidence

10% Fair Confidence

20% Indicative (not stat significant)

No of years 10 1.9 Ave accidents per year

Year No Year Accident Total Significance

1 2008 2 56.6% Not Significant of increase over the average


3 2010 5 4.4% High Confidence of increase over the average

4 2011 1 15.0% Indicative (not stat significant) of decrease below the average









Figure 3-3 – Collision locations (Jan 2014 to Dec 2018)

Table 3-1 – Collision summary

Ref. Year Severity Light Surface Weather Direction Manoeuvres Contributory

factors

0000831 2015 Slight Dark

& Lit

Wet Rain 1 Car SN

2 HGV

<3.5 NS

1 Going

ahead other

2 Going

ahead other

1 Careless/

reckless/ in a

hurry

0000813 2015 Slight Dark

& Lit

Snow Snow 1 Car SE

NE

2 Car NW

SE

1 Turning

right

2 Going

ahead

another

1 Junction

overshoot

1 Distraction

in vehicle

0004312 2015 Slight Light Dry Fine 1 Car SN

2

Pedalcycle

SN

1 Going

ahead other

2 Going

ahead other

1 Passing too

close to

cyclist, horse

rider or

pedestrian

0001668 2016 Slight Light Dry Fine 1 HGV

<3.5 SE

NE

2 Car NS

1 Turning

right

2 Going

ahead other

1 Failed to

look properly

0004312

0000813

0001095

0001668

0000831

0000287

0000180



Ref. Year Severity Light Surface Weather Direction Manoeuvres Contributory

factors

0000180 2017 Slight Light Wet Fine 1 Car SE

NE

2 Car NE

SW

1 Turning

right

2 Going

ahead other

1 Failed to

look properly

0000287 2017 Slight Light Dry Fine 1 Car NS

2 Car SN

1 Going

ahead right-

hand bend

2 Going

ahead other

1 Careless/

reckless/ in a

hurry

1 Poor turn or

manoeuvre

0001095 2018 Slight Light Dry Fine 1 Car EN

2 HGV

<3.5 NS

1 Waiting to

turn right

2 Going

ahead other

1 Failed to

judge other

persons path

or speed

3.4.3 Of the four collisions recorded linked to the junction, three were travelling northbound on the

A702 and turning right. The specific minor road cannot be specified from collision data available.

Two of these collisions, both of a slight severity, cite failure to look properly as a contributory

factor, and the remaining collision overshot the junction. This highlights that visibility issues,

junction complexity and layout could have attributed to these collisions occurring. All collisions

appear to involve oncoming traffic, and no rear end shunts are recorded.

3.4.4 The final collision related to the junction was a car turning right from the A703 on to the A702,

colliding with an HGV. Failure to judge other person’s path or speed was a contributory factor for

this collision. Further investigation into the layout and driver behaviour at the junctions is studied

in Sections 4 and 5.

3.5 Annual Accident Rate (AAR) Comparison

3.5.1 The Annual Accident Rate (AAR) has been calculated for the junction between January 2013 and

December 2017. As part of the conflict study, the AADF for the junction was calculated to be

20,860. Methods used to determine this value to be further discussed in Section 6.

3.5.2 The AAR is the number of collisions per million vehicle kilometres (108 vkms) occurring on a route.

It is calculated using the following formula:

𝐴𝐴𝑅 = 𝑁𝑜 𝑜𝑓 𝑐𝑜𝑙𝑙𝑖𝑠𝑖𝑜𝑛𝑠 × 108

𝐷𝑎𝑦𝑠 𝑖𝑛 𝑃𝑒𝑟𝑖𝑜𝑑 × 𝑇𝑟𝑎𝑓𝑓𝑖𝑐 𝐹𝑙𝑜𝑤 × 𝑟𝑜𝑢𝑡𝑒 𝑙𝑒𝑛𝑔𝑡ℎ

𝐴𝐴𝑅 = 7 × 108

1825 × 20,860 × 0.5

𝐴𝐴𝑅 = 36.8 𝑎𝑐𝑐/108𝑣𝑒ℎ𝑘𝑚



3.5.3 This value can be compared with the values for similar roads both nationally (A class) and in the

Scottish Borders and Lothian areas obtained from Tables 5(b) and 5(c) in the Reported Road

Casualties Scotland 2017. Values obtained are compared and summarised in Table 3-2.

Table 3-2 – Annual Accident Rate (AAR) comparison

A702/A703 Junction

AAR(108 vkms)

Similar Scottish

‘A’ class AAR

(108 vkms)

Deviation from

Scottish ‘A’ class

average

Similar Scottish

Borders and

Lothian AAR (108

vkms)

Deviation from

Scottish Borders

and Lothian

average

36.8 9.73 279% 10.9 239%

3.5.4 This comparison demonstrates that the accident rate at the junction under investigation is much

greater than that of comparable roads nationally and in the Lothians and Scottish Borders.

3.5.5 The high AAR value reflects that the number of collisions that have occurred in the five-year time

frame is great when compared to the AADF and length of section under investigation. Therefore,

this further demonstrates alongside collisions specifically related to the junction that the

frequency of collisions in the vicinity of the junction is high and improvements to the junction

should be investigated.



4 Site Investigation

4.1 Junction Layout

4.1.1 The current layout of both junctions is shown in Figure 4-1 and can be described as a non-

standard layout.

Figure 4-1 – Junction layout taken from Old Pentland Road footpath facing south

4.1.2 Guidance from CD 123 Geometric design of at-grade priority and signal-controlled junctions was

used to assess the suitability of the current junction layout between the A702 and minor roads

under current traffic demand.

4.1.3 Traffic flow data from the conflict study, as discussed in Section 2.2, has been used to estimate

the appropriate layout to accommodate the current traffic demand at the junction. Flows from

the A703 and Old Pentland Road have been accumulated to give an overall value for minor roads.

4.1.4 The existing T-junction layout would have to meet a maximum 2-way AADT of 300 for the minor

road and 13,000 for the major to comply with standards. However, based on traffic flow data

obtained, although major road 2-way AADF would allow for a simple T-junction, the minor road

flows would not. Figure 4-2 shows that a more appropriate layout to accommodate the current

traffic demand at the junction would be ‘Other junction type’. This highlights that the current

layout is insufficient when compared to the traffic flows recorded and capacity required to

accommodate the flows, and consideration into changing the current layout should be given.

Old Pentland Road

A703

A702



Figure 4-2 – Level of provision for junctions on single carriageway roads from DMRB

CD 123

4.2 Visibility

4.2.1 Junction visibility requirements are contained in DMRB CD 109 and CD 123 (Figure 4-3). The

design speed for the A702 at Hillend is calculated to be 85A kph. The full design speed calculation

is found in Appendix B. From Figure 4-3, the desirable minimum stopping sight distance for a

road with design speed 85 kph is 160m and the minimum visibility from a minor road entering a

major road of design speed 85 kph is 160m.

A702/A703

Hillend Junction



Figure 4-3 – Design geometric parameters

4.2.2 Due to the constant volume of traffic entering and exiting both junctions, measuring visibility

from the junctions in line with CD 123 in a safe manner was not possible. However, it was found

during a drive through of the site that visibility is poor from both junctions on to the A702.

4.2.3 Since measurements on site could not be done, a desktop analysis has been undertaken to better

understand constraints causing visibility issues experienced at the junction. It was found that the

road geometry of the A702 will prohibit the full 160m stopping distance being met due to

curvature in the road. On approach to the junction, the A703 runs almost parallel to the A702.

As a result, drivers entering the mainline from the A703 must look over their left shoulder in order

to check for northbound traffic. Assuming cars are approaching the junction at a perpendicular

angle, the estimated distance they can see southbound is approximately 90m before the bend

prevents further visibility.

4.2.4 However, it was found during the site visit that cars were angling to help merge better with the

traffic flow. Alignment varied depending on the direction the vehicle wished to turn on to the

A702. However, in each instance, the projected visibility of northbound traffic was reduced

further. Angles varied but an estimate of between 60m and 80m is predicted for both left and

right turns.

4.2.5 Old Pentland Road junction contains a stop sign traffic control. This highlights that visibility from

the junction is restricted such that it is mandatory for road users to stop before entering the

major road. It is estimated through desktop analysis of the junction that if a road user is

positioned perpendicular to junction markings, the maximum visibility of northbound traffic is

approximately 100m, which is also below the standard requirement of 160m.

4.2.6 This indicates that for both junctions, visibility of mainline traffic is restricted by the horizontal

alignment of the road. In both southbound and northbound directions, there are bends in the



road with radii 226m and 141m respectively. This results in minimum visibility from the minor

road and minimum stopping sight distances not being met.

4.3 Road Surface Condition Review

4.3.1 The surface conditions of trunk roads are regularly surveyed on behalf of Transport Scotland for

input in to the IRIS database.

4.3.2 Although Amey is not accountable for the road markings of the minor roads, investigation into

both junctions approximately 50m back from where they join with the A702 was carried out.

4.3.3 During a site visit, it was found that the High Friction Surfacing (HFS) has become very worn

around the bell mouth of the A703 junction, as shown in Figure 4-4. Give way lines at both

junctions were extremely worn. Although no collisions recorded in the last five years have been

linked to poor road markings or road conditions, the faded road markings could cause hesitation

and confusion in road users, especially those unfamiliar with the junction. Therefore, a

recommendation is made to refresh the markings although they are the responsibility of the

Midlothian Council.

Figure 4-4 – Worn high friction surface on the A703

Sideways Force Coefficient Routine Investigation Machine (SCRIM)

4.3.4 On behalf of Transport Scotland, the condition of the road surface is constantly surveyed, with

data collected uploaded into the IRIS database. This has been used to help analyse the current

condition of the A702 trunk road to determine if there are any areas that require remedial

measures.



4.3.5 The sideways coefficient of friction (SCRIM) of surfaces is used to show the level of grip the road

provides in wet conditions. The grip levels are measured in accordance with CD 236, Surface

course materials for construction revision 3. Actual SCRIM levels are found and compared to an

investigatory level.

4.3.6 The SCRIM survey undertaken in 2018 shows that the wet skid resistance of the road at the

entrance to both junctions is above IL, shown in green and yellow in Figure 4-5. This highlights

that at this location, there is no SCRIM deficiency. Sections highlighted in red to the north and

south of the junction represent areas with values below the IL. However, as shown in Section 3,

there were no collisions related to the road surface condition. Additionally, SCRIM levels are

checked annually as part of an independent review, CS 228, Skidding Resistance. No sites within

the investigatory location were highlighted in the 2018 recommendations. Both of these factors

show that although the SCRIM is below IL, it is not currently attributing to collisions at this

junction.

Figure 4-5 – A702 Hillend SCRIM summary

Rutting

4.3.7 Rutting is a measure of deformation of the carriageway due to traffic loading. Aquaplaning can

be caused as water can collect in the ruts. Rutting depth is regularly monitored to determine the

level of deformation on the carriageway due to traffic loading. Figure 4-6 shows the results of the

2018 rutting survey at the junction, where no evidence of any serious rutting is noticeable. As

previously stated, since there are no collisions attributed to the road surface condition, this

validates that the rutting at the junction is not a contributing factor.



Figure 4-6 – A702 Hillend rutting summary

Texture Depth

4.3.8 Texture is also used as an indication of surface quality. It is a measure of the macro texture,

which gives insight into the road’s ability to shed water. Low texture levels could result in a film

of water forming on the surface, which reduces the skid resistance and can cause a potential

increase in the risk of aquaplaning.

4.3.9 Texture depth results are shown in Figure 4-7. The texture depths at the junction under

investigation are all above the IL and therefore do not require further attention.

Figure 4-7 – A702 Hillend texture depth summary

4.4 Road Signs and Markings

4.4.1 As part of this investigation, signage and road markings within the study area have been

reviewed. As previous, 50m of both junctions from the junction with the A702 have been assessed

since the minor roads are not part of the South East Trunk Road Network within Amey’s

responsibility. Signs and markings were investigated during a site visit in August 2018 and results

are shown in Table 4-1.

4.4.2 A Vehicle Activated Sign (VAS) is present to the north of the junction. The purpose of this VAS is

to warn southbound vehicles travelling above a speed threshold of the approaching junction and

to slow down. The VAS was monitored during a site visit in August 2018, during this time the sign



was not activated once. It is unclear if speeds during the site visit were reaching threshold values

for the VAS sign to be activated. It is known that this VAS will be part of a rolling update

programme and should be upgraded shortly. Relevant maintenance teams have been notified of

the potential that the sign is not working correctly.

4.4.3 40-mph speed limit signs are placed at the junction between the A702 and A703. Since there is

no change in speed limit between the roads and gateway signs are not required, it is assumed

that these signs are in place as repeater signs. Traffic Signs Manual Chapter 3 dictates that after

a 40-mph terminal sign, there should be a repeater sign 250m from the gateway and then a

maximum of every 500m thereafter. The signs in place are too large compared to the

recommended repeater sign diameter and are not 250m away from the gateway signs. However,

signs are not misinforming road users of the speed limit. Therefore, it is recommended to do

nothing and leave the signs in place.

4.4.4 The give way and stop lines and markings at the A703 and Old Pentland Road junctions have

become very worn. It is recommended to refresh junction markings using MMA in order to make

road markings more durable, which would be the responsibility of Midlothian Council.

4.4.5 The bollard between the A703 and Old Pentland Road junction has been damaged and has lost

its reflective surface and should be replaced. This has been passed on to routine maintenance.

Table 4-1 – A702 A703 Hillend junction signs and markings

VAS situated 100m north of the junction.

Visibility partially obstructed by

vegetation. Sign part of an upgrade

programme to be replaced.



4.4.6

Advance directional sign obstructed by

foliage on southbound approach to

junction.

4.4.7

Damaged bollard between the A703 and

Old Pentland Road junctions – passed on

to routing maintenance.

4.4.8

40-mph sign too large to be a repeater

sign and not a gateway sign (part of

Midlothian Council’s network).



4.4.9

Give way line at A703 (Midlothian Council

network) junction very worn.

4.5 Bend Assessment

4.5.1 All signage and markings around the junction under investigation have been reviewed in

accordance with Advice & Procedure Guide (APG) E115. This document recommends the signs

and markings required for a bend based on its design speed of 85-kph and individual radius.

4.5.2 Figure 4-8 shows bend locations. In total, there are four bends to be considered.

Figure 4-8 – Bend categories from APG E115

4.5.3 The bend assessment highlighted three bends that require further measures to ensure compliance

with APG_E115, as shown in Table 4-2.

Bend 2

Bend 3

Bend 4

Bend 1



Table 4-2 – APG_E115 Bend assessment results

Bend Bend

Category

Compliance

(Y/N)

Existing signage/ road

markings

Signage/road markings

required

1 D N 100mm wide edge and

centre lines

Hazard posts, bend warning

signs and chevrons

2 D N 100mm wide edge and

centre lines

Hazard posts, bend warning

signs and chevrons

3 B N 100mm wide edge and

centre lines and bend

warning signs

Hazard posts

4 E N 100mm wide edge and

centre lines, bend warning

signs hazard posts and

chevron warning signs

SLOW road markings

4.5.4 Due to the narrow width available and existing footpaths at Bends 1 to 3, it is not feasible to

install verge marker posts or chevrons. However, for Bends 1 and 2, the installation of bend

warning signs will greatly warn road users of the horizontal alignment. For Bend 2, it is also

possible to install reflectors along the existing vehicle restraint system (VRS) at this bend, and

further investigation into the viability and benefits of installation should be investigated.

4.5.5 Bend 4 requires ‘SLOW’ road markings to be installed adjacent to existing bend warning signs.

4.6 Drainage

4.6.1 Drainage at this junction is provided by top entry gullies situated at various positions around the

junction. All gullies appear to be in good condition. Figure 4-9 displays a gully located on the

A702.



Figure 4-9 – Top entry gully, A702 Hillend

4.6.2 The locations of the gullies at the junction and its approaches are detailed in Figure 4-10. In

terms of routine maintenance there are no planned drainage schemes, or any drainage issues

raised at this junction. Two of the seven collisions recorded occurred when the road surface was

wet. Therefore, there is no significant trend in wet surfaces and collisions, which indicates no

drainage issues at the junction.

4.6.3 A site visit was undertaken shortly after rain had occurred. There was no standing water present

during this time, which further indicates there is no immediate drainage problem.

Figure 4-10 – A702/A703 Hillend top entry gully locations



4.7 Non-Motorised Users Provision

4.7.1 There is limited provision for non-motorised users at this junction. North of the junction, there is

a footpath on both sides of the A702 connecting Hillend to the City of Edinburgh. A continuous

pedestrian footpath is provided on the northbound carriageway side of the A702 south of the

junction. Two uncontrolled pedestrian crossings are located within the vicinity of the junction

under investigation. One crossing is located on the A703, and a provision of dropped kerb and

tactile paving is located at the junction of Old Pentland Road. The A702 footway and crossing

provision is shown in Figure 4-11.

Figure 4-11 – A702 Footway provision at A702/A703 Junction

4.7.2 During the conflict study, pedestrian counts were undertaken, focusing on the number of

pedestrians that cross the junction or use either the east or west footway for Old Pentland Road

or the A703. Results from the study are shown in Table 4-3.

Figure 4-12(a)

Figure 4-12(b)

Dropped kerb and

tactile paving

Uncontrolled

pedestrian crossing



Table 4-3 – Pedestrian crossing count results

Road Old Pentland Road

(Number of people)

A703

(Number of people)

Crossing 8 4

East kerbside 46 4

West Kerbside 11 12

4.7.3 More people were recorded using the footway and crossing facilities at Old Pentland Road than

the A703. Pedestrian usage overall was low, with the maximum of 46 people recorded using the

east kerbside of Old Pentland Road compared to four at the A703. Double the number of

pedestrians crossed Old Pentland Road than the A703. When comparing results for the west

kerbside for both minor roads, similar numbers of pedestrians were recorded.

4.7.4 This footpath varies in width (1-1.5m) and is often overgrown by vegetation, as shown in Figure

4-12. Location of where photographs have been taken are shown in Figure 4-11. On the A703

and Old Pentland Road a continuous pedestrian footway is provided on the southbound

carriageway side.

Figure 4-12 – (a) Footpath overgrown with vegetation (b) Narrow footpath

4.7.5 There is an uncontrolled pedestrian crossing on the A703 with tactile paving and dropped kerbs.

However, vegetation has grown around the kerb and tactile paving shown in Figure 4-13, which

should be removed to ensure maximum effectiveness of the crossing. Since the crossing is on the

A703, it is the responsibility of Midlothian Council to maintain it.

(a) (b)



Figure 4-13 – Vegetation at pedestrian crossing

4.7.6 A drop kerb with tactile paving is present on Old Pentland Road that indicates a pedestrian

crossing, shown in Figure 4-14. However, this crossing points towards the centre of the junction

where there is no area of footpath to cross to. Although this is part of Old Pentland Road and

therefore part of the local authority road, a recommendation is made to remove the drop kerb

and tactile paving in order to improve the safety of vulnerable users at this junction.

Figure 4-14 – Old Pentland Road tactile paving and drop kerb



4.7.7 Two bus stops are situated 50m south of the junction on the A703 on either side of the

carriageway to accommodate buses travelling in both directions, shown in Figure 4-15. These bus

stops are served every 30 minutes by Lothian Buses services 15 and X15.

Figure 4-15 – A702/A703 Hillend bus stop locations

4.7.8 One collision involving a non-motorised user has been recorded in the last ten years. This collision

involved a cyclist and a car, where the car passed too close to the cyclist.

4.7.9 Additionally, the Midlothian Council Capital View walking route begins 300m north of the junction

at the Midlothian Snowsports Centre junction. The route continues around the existing ski slope

and across the northern slopes of the Pentlands. The proximity of this walking route may attract

additional non-motorised users to this area. The walking route and starting point are shown in

Figure 4-16.

Bus stops



Figure 4-16 – Capital view walking route (Walkhighlands)

4.7.10 In order to improve facilities for non-motorised users at this junction, vegetation should be

trimmed back from footpaths and any incorrect tactile paving should be removed to improve

safety at this junction.

4.8 Street Lighting

4.8.1 Lighting columns are in place at all arms of the junction. On the A703 and Old Pentland Road,

columns are provided from the 40-mph gateway towards the junction. On the A702, lighting

columns are provided from the 40-mph gateway to the City of Edinburgh. Street lighting provision

at this junction is shown in Figure 4-17, with an example of street lighting on site shown in Figure

4-18.



Figure 4-17 – Street Lighting Provision at A702/A703 Hillend Junction

Figure 4-18 – Lighting Columns, A702/A703 Junction



4.9 Swept Path Analysis

4.9.1 Swept path analysis has been used to calculate the predicted path of vehicles undertaking various

movements at this junction. It was found that all manoeuvres except turning left from either

minor junction on to the A702 were acceptable. Therefore, results shown are focused on road

users turning left from minor roads.

4.9.2 Figure 4-19 shows the swept path analysis of a private car making a left turn from the A703 to

the A702. The blue line represents the swept path of the vehicle body and the red line represents

the path of the vehicle wheels. This shows that private cars must use the whole of the opposing

carriageway in order to successfully make this turn, increasing the chance of collision for vehicles

making this manoeuvre.

Figure 4-19 – Swept path analysis for private car turning left from A703 junction

4.9.3 Since the private car was not able to successfully perform the manoeuvre without using the

opposing carriageway, this indicates that vehicles larger than a private car (e.g. Large Goods

Vehicles [LGVs] and HGVs) are also unable to perform this turn within the boundaries of the lane.

This is due to the small radius turn required to turn left. Therefore, analysis was not repeated for

other larger vehicle types.

Swept path of vehicle body

Swept path of vehicle wheels



4.9.4 During the conflict study, the maximum number of LGVs and HGVs that performed this

manoeuvre per day was two vehicles, which equated to an average of 1% of the traffic flow

turning left from the A703 per day. This low proportion of larger vehicles performing the

manoeuvre further demonstrates the difficulty they face.

4.9.5 Figure 4-20 shows an example of a car turning left from the A703 on to the A702 and having to

encroach the northbound carriageway to successfully perform this manoeuvre, recorded during

the conflict study.

Figure 4-20 – Road user turning left from A703: (a) beginning to turn (b) encroaching

NB carriageway (c) same as previous (d) beginning to recover lane boundary

4.9.6 Figure 4-21 shows the swept path analysis for private cars turning left from Old Pentland Road.

They can successfully turn on to the A702 without encroaching the opposing traffic lane. However,

drivers are required to use full lock steering to do so. As a result, if this manoeuvre is poorly

executed, it is likely to result in vehicles encroaching on the opposing carriageway. Vehicles larger

than a private car (e.g. LGVs and HGVs) are unable to make this manoeuvre within the boundaries

of the carriageway.

(b) (a)

(c) (d)



Figure 4-21 – Swept path analysis for private car turning left from Old Pentland Road

junction A703

4.9.7 Vehicles are likely to encroach the red hatching in order to make this turn more easily. This

manoeuvre was found to be common during an assessment of the conflict study. Figure 4-22

gives an example of a road user encroaching nearside hatching while turning left.

Figure 4-22 – Road user turning left from Old Pentland Road conflict study

encroaching nearside red hatching

Swept path of vehicle body

Swept path of vehicle wheels

(a) (b)



4.10 Future Developments

4.10.1 Several areas of development have been highlighted in the vicinity of the junction under

investigation which would influence trip generation. It is known that the capacity of the junction

is currently exceeded, and therefore any further developments will not result in over capacity of

the junction but add to the existing issue.

4.10.2 As part of the Edinburgh City Deal, it is known that there is going to be a new link road constructed

between the A701 and the A702. This is also likely to increase trip generation at the A702/A703

Hillend junction. Further information will be required on this proposal, alongside all other

developments, to establish exactly how they will impact traffic movements in the area before

finalisation of any options.



5 Site Observations

5.1 Overview

5.1.1 A site visit and concurrent video survey independent of the conflict study were undertaken to

assess the junction. A dash camera was used to carry out the video survey. These activities were

carried out to help understand how the junction performed in terms of driver behaviour of road

users as well as to highlight any other issues with road condition.

5.1.2 The site visit was undertaken in August 2018 and the video survey in January 2019 between

14:30 and 15:30. During the survey, all movements available at the junction were recorded except

for turning left from the A703 to the A702 southbound. The survey vehicle was unable to safely

turn left from the A703 to the A702 southbound (as noted in Section 4.9) so this movement was

not carried out.

5.2 Driver Behaviour

A703 from A702 Southbound

5.2.1 Through visual assessment, it was established that drivers turning southbound from the A702 to

the A703 can perform this manoeuvre with only a limited reduction in speed. This was executed

by driving over the red hatching areas present at the outside of the junction and between the

lanes. This manoeuvre was recorded during the site visit and video survey, as shown in Figure

5-1. The intended traffic calming effect of vehicles slowing as they approach the junction is lost.

Figure 5-1 – Vehicle turning from the A702 SB to the A703 crossing the red hatching

during: (a) site visit (b) video survey

5.2.2 As a result of vehicles crossing this hatching, road users approaching Old Pentland Road junction

are stopping short of the stop line to allow road users to cross the hatching when entering the

A703 from the A702 southbound reducing the vehicles on Old Pentland Roads visibility. This is

shown in Figure 5-2.

(a) (b)



Figure 5-2 – Road user stopping short of Old Pentland Road stop line

5.2.3 Drivers were observed edging forward from either minor junction in an attempt to join the A702.

This caused road users travelling southbound on the A702 to encroach on to the oncoming

carriageway to avoid a collision.

Old Pentland Road from A702 Northbound and Southbound

5.2.4 Joining Old Pentland Road from the A702 was recorded twice during the survey, once northbound

and once southbound. In both directions, the survey vehicle had to brake sharply after entering

Old Pentland Road due to narrow road width and oncoming traffic. Photographs taken during the

northbound and southbound direction are shown in Figure 5-3 and Figure 5-4 respectively.

Figure 5-3 – A702 SB to Old Pentland Road: (a) prior to turning, sharp radii produced

by hatching (b) mid turn, narrow carriageway ahead

(a) (b)



Figure 5-4 – A702 NB to Old Pentland Road: (a) prior to turning, large turning angle

required (b) post turn, oncoming traffic and narrow carriageway

5.2.5 In both occurrences, opposing vehicles were still in their lane. However, this was found to not

always be the case, shown in Figure 5-5. This is caused by the narrow carriageway on approach

to the junction.

Figure 5-5 – Old Pentland Road vehicle using opposing traffic lane

5.2.6 Alongside road users turning into the A703, it was apparent that drivers entering Old Pentland

Road from the A702 were driving over red hatching present as well. One reason for this is that it

allows road users to enter the junctions at faster speeds, since discounting the hatching increases

the turning radii and the width of the junction access. The hatching helps produce a more curved

(a) (b)



access and egress to both junctions, but since this edge line is not reinforced through kerbing, it

is easy for users to disregard. Examples of vehicles crossing the hatching while entering the A703

are shown in Figure 5-1.

A702 Northbound from A703

5.2.7 When using the junction during the site visit, it was notably onerous to turn right on to the A702

from the A703. This was due to the skewed approach making it difficult for drivers to check both

directions, as shown in Figure 5-6. Difficulty checking both traffic directions makes gap

acceptance harder which can lead to driver frustration due to long waiting times.

Figure 5-6 – Visibility difficulties at the A702/A703 junction

5.2.8 It was observed that road users approaching the junction from the A703 were using the opposing

traffic lane. This allowed road users to better align with the give way line at a right angle to

increase visibility and be able to safely check the mainline in both directions before joining the

A702. The use of the opposing lane greatly increases the probabilities of a head on collision.

However, there is no historical evidence of this collision type occurring at this junction.

A702 Southbound from Old Pentland Road

5.2.9 As discussed in Section 4.9, turning left from Old Pentland Road on to the A702 requires full lock

steering in order to complete the manoeuvre without encroaching the opposing traffic lane. When

making this manoeuvre in practice, it was found that many vehicles cross over the nearside red

hatching to better align with mainline traffic and decrease the angle required to turn on to the

A702. Figure 5-7 shows a road user crossing over hatching to turn on to the A702.



Figure 5-7 – Old Pentland Road to A702 SB, vehicle crossing nearside hatching: (a)

begins to turn as Amey vehicle turns into A702 (b) continues to turn

Priority Confusion

5.2.10 During the video survey, in one instance it was unclear who had priority due to the two junctions

neighbouring each other. The survey vehicle was travelling northbound on the A702, turning on

to the A703 and the other vehicle was turning from Old Pentland Road on the A702 southbound.

5.2.11 The survey vehicle and user turning from Old Pentland Road decided to move off at the same

time, shown in Figure 5-7, as it was unclear to the vehicle entering the A702 whether the survey

vehicle was intending to turn on to the A702 or Old Pentland Road due to the close proximity of

the junctions. No collision occurred, however this is a clear point of conflict.

5.2.12 It is clear from site investigations that the current layout of the junctions is causing conflict

entering and exiting from the A702 both northbound and southbound. Alignment and widths of

the junctions are causing vehicles to disregard current road markings such as centre lines and

red hatching to allow for angles and positioning more desirable to road users. Such issues are

having a consequential effect on other road users simultaneously using the junction. For example,

users are not reaching the stop line on Old Pentland Road to allow vehicles entering the A703 to

cut across red hatching. Such manoeuvres are causing serious points of conflict, and therefore

remedial measures must be implemented to alter driver behaviour at this location.

(a) (b)



6 Conflict Study

6.1 Background

6.1.1 The purpose of this conflict study was to identify any difficulties encountered by road users at

the A702/A703 Old Pentland Road junction. Although collision data does show a trend in right

turn collisions from the A702 on to the A703, the conflict study was undertaken to provide a more

comprehensive overview of the junction, behaviour of road users and any near-miss incidents.

6.1.2 24-hour video cameras were used to carry out the surveys during Spring 2019 over a seven-day

period to record the interaction of traffic at the junction. For all seven days, turning counts were

recorded. For four of these days, footage was assessed in terms of conflicts. Although possible

to assess conflicts for the full data set, it was deemed that assessing two weekend and two

weekdays would allow sufficient data for analysis. Camera locations can be found in Appendix C.

6.1.3 This section outlines the results and conclusions from the survey. Data has been summarised

with a full set of survey results available upon request.

6.2 Survey Methodology

6.2.1 The conflict study was carried out using The Royal Society for the Prevention of Accidents (RoSPA)

Road Safety Engineering Manual as a guideline. Conflicts within the Manual are organised in terms

of severity for situations where, if the movements of one or more road user were to stay constant,

there is a risk of a collision occurring.

6.2.2 RoSPA severities do not categorise the specific manoeuvre that caused the conflict. Instead, it

assesses the response road users have to a conflict. To better understand the manoeuvres and

decisions that were attributing to conflicts at the investigation site, data was first categorised

based on predefined conflict descriptions. A major influence on this method of data processing

was due to the unusual layout of the neighbouring junctions, which resulted in a variety

manoeuvres from which conflicts could arise. Conflict descriptions are shown in Table 6-1.

6.2.3 Once a conflict type was established, a severity could be awarded. As previously stated, severities

used are based on guidelines from RoSPA. During analysis of the conflict study data, it was found

that several road users were not using the road layout as designed. However, no other cars were

affected by these actions, so no actual conflict arose. An additional severity of zero has been

added to the severity rankings to account for such scenarios where although a conflict was not

instigated, there was great potential for one to have occurred. Severities are shown in Table 6-2.



Table 6-1 – Conflict descriptions

Conflict

Type Incident Description Comment

1 Crossing of centre line on A702 due to wrongly

positioned vehicles at junction exits.

-

2 Cutting hatchings & crossing into wrong lane on

A703/Old Pentland Road.

Split further into the minor

roads they occurred on.

3 Vehicles mounting pavement due to queuing traffic

when exiting A702.

-

4 Unusual Manoeuvres. U-turns in junctions, using

opposite lane, cutting across

hatching.

5 Vehicles not stopping at exit of Old Pentland Road. -

6 Crossing centre line when moving from junction to

junction/junction A702 NB.

Split further into the minor

roads the vehicle exited.

Table 6-2 – RoSPA conflict severities

Severity Description

0 Manoeuvre where only one vehicle is involved with the potential to cause conflict

(ie road users crossing into the wrong lane but no oncoming traffic, so no conflict

occurs).

1 Precautionary conflict (i.e. braking for vehicle waiting to emerge, precautionary

lane change or anticipatory braking).

2 Controlled braking or lane change to avoid collision, but with ample time for

manoeuvre.

3 Rapid deceleration, lane change or stopping to avoid collision, resulting in a near

miss. No time for steady controlled manoeuvre.

4 Emergency braking or violent swerve to avoid collision resulting in very near miss

or occurrence of a minor collision.

5 Emergency action followed by collision.



6.3 Peak Hours

6.3.1 During weekday surveys, the AM peak was observed between 07:15 and 08:45, with the PM peak

recorded between 16:30 and 17:30. During the weekend surveys the AM peak was observed

between 11:00 and 12:00, with one PM peak recorded between 12:30 and 13:30 and the other

between 13:30 and 14:30.

6.3.2 Over the four-day conflict survey period, a total of 96 hours of video footage was assessed and

analysed for any trends in conflicts. In total, 34,072 vehicles were recorded entering or exiting

between the A702 and either Old Pentland Road or the A703.

6.3.3 Of the 34,072 users recorded across all eight turning movements described in Section 2.2, 5,876

conflicts were recorded. Table 6-3 shows the breakdown of severities of each conflict type.

Table 6-3 – Breakdown of severity

Conflicts

Severity 1 2 3 4 5 6 Total

0 0 4501 29 453 159 78 5220

1 284 16 5 21 0 0 326

2 68 4 1 19 1 0 93

3 51 0 2 4 0 0 57

4 0 0 0 0 0 0 0

5 0 0 0 0 0 0 0

Total 403 4521 37 497 160 78

6.3.4 The most common conflict that occurred was Type 2. Vehicles were frequently cutting hatching

and using the oncoming minor road lane when entering or exiting either junction. However, it

was found that Type 2 situations were rarely awarded severity 1 or above since this conflict

primarily occurred with a single road user and when there was no oncoming traffic.

6.3.5 Where severities of 1 or above were awarded, 95% were given severity ratings of 1 or 2. This

highlights that where a conflict did involve more than one road user, only precautionary or

controlled braking was required to mitigate a collision. No conflicts were awarded a severity of 4

or 5, showing that no road users had to emergency brake or violently swerve in a near miss or

minor collision.



6.3.6 The percentage of conflicts compared with the traffic flow for all movements is detailed in Table

6-4. A breakdown per day is shown.

Table 6-4 – Conflicts compared with traffic count

Day Traffic Count Total Conflicts Conflicts (%)

Saturday 23rd March 17578 1404 7.99

Sunday 24th March 15951 1351 8.47

Monday 25th March 22262 1709 7.68

Tuesday 26th March 21942 1764 8.04

6.3.7 On average, 7.33% of the traffic count resulted in a conflict. However, considering that conflicts

are related to users utilising the A703 or Old Pentland Road junctions, and that an average of

56% of traffic data recorded solely related to road users using the A702, this value of conflicts

proportional to traffic counts increases to approximately 14% when discounting traffic data not

directly related to the junction.

6.4 Vehicle Speed

6.4.1 As stated in Section 2.1, the junction is subject to a 40-mph speed limit.

6.4.2 Traffic speeds have been investigated using data recorded during the survey. Figure 6-1 below

shows the location the traffic speeds were taken.

Figure 6-1 – Traffic counter locations



6.4.3 The mean and 85th percentile speed as well as the percentage of vehicles exceeding the speed

limit is displayed in Table 6-5 for the seven-day survey period.

Table 6-5 – Vehicle speed

6.4.4 Figure 6-2 and Figure 6-3 display the speed behaviour of road users travelling northbound and

southbound respectively. Southbound speeds have been calculated at ATC1, located north of the

junction, to examine the speed of road users travelling southbound towards the junction. This is

also mirrored in the data depicting northbound speeds at ATC2, to allow the speeds of users

travelling northbound towards the junction to be assessed.

Figure 6-2 – 85th percentile speed at ATC1 southbound

0

10

20

30

40

50

60

00:00 03:00 06:00 09:00 12:00 15:00 18:00 21:00 00:00

Speed (

mph)

Time (hrs:mins)

Weekday 85%ile

Weekend 85%ile

Speed Limit

Direction 7-day

average

Posted Speed

Limit (mph)

% >

Speed

Limit

(mph)

Mean

Speed

(mph)

85th Percentile

Speed (mph)

Southbound 9,014 40 2.9 30.0 35.7

Northbound 10,846 40 4.4 31.2 36.0

2-way 19,860 40 3.7 30.6 35.9



Figure 6-3 – 85th percentile speed at ATC2 northbound

6.4.5 It is evident that road users tend to exceed the speed limit during quieter hours between midnight

and 06:00 when travelling northbound. For both directions, there is a decrease in 85th percentile

speed during the day – between approximately 09:00 and 18:00 for southbound and 06:00 and

21:00 for northbound traffic. A significant trough is found in data for northbound travel at

approximately 08:00 weekdays. This trend can be attributed to the higher volume of vehicles at

this time. Maximum and minimum 85th percentile speeds calculated of users travelling southbound

was higher than those travelling northbound. More traffic travelled northbound, so higher traffic

flows will prohibit faster speeds.

6.4.6 Considering the seven collisions recorded between January 2013 and December 2018, there was

no strong correlation between period of higher speeds and collisions. One was recorded between

midnight and 06:00, three between 06:00 and 09:00 and the remainder during the day, between

09:00 and 19:00. It is possible that periods where there are more road users are causing more

collisions due to the increased driver confusion regarding junction layout.

6.4.7 Although only a small portion of conflicts were found to have a severe effect on road users by

causing emergency breaking, a very close near miss or a minor collision, the proportion of minor

severities was much greater. This highlights that although there is not a high percentage of severe

conflicts occurring at present, there is high potential for this to occur in the future based on the

amount of existing near-misses. Conflicts of any severity arising should be mitigated as much as

possible.

6.4.8 Traffic speeds show that a small proportion of traffic exceeds the speed limit, generally during

the night. Daytime speeds are restricted by the traffic flow volumes.

0

5

10

15

20

25

30

35

40

45

50

00:00 03:00 06:00 09:00 12:00 15:00 18:00 21:00 00:00

Speed (

mph)

Time (hrs:mins)

Weekday 85%ile

Weekend 85%ile

Speed Limit



7 Remedial Options

7.1 Overview

7.1.1 Following detailed analysis of the site under investigation, remedial measures have been identified

in terms of potential to improve the overall safety of the junction. Options have been produced

using data from a desktop study of the area. Therefore, some assumptions made will require

further investigation should they be considered further.

7.1.2 Three options have been created, ranging from short-term implementation measures to long-

term, high cost junction layout alterations. The feasibility and buildability of each option varies

considerably.

7.1.3 All options reviewed will have an impact on the existing Local Authority side roads. Therefore,

liaison with Midlothian Council is required since the minor roads are part of their network.

7.2 Remedial Measures

7.2.1 Remedial measures reviewed are shown in Table 7-1. Advantages, disadvantages and estimated

cost ranges are also shown. Reasons for the creation of each option are also outlined to establish

the necessity of the measure and what issues it can improve at the junction. Drawings for each

option can be found in Appendix D.

7.2.2 Consideration into signalising the junction using the existing layout was also assessed. A Linsig

model projecting the effect of signals was created, focusing on the AM and PM peaks. Data

collected from the traffic counts discussed in Section 2.2 was utilised. The model found that

signalisation of the existing layout would results in oversaturation of the junction. AM peak results

showed that saturation of up to 119% would be reached. Is it estimated that if 85% of junction

capacity is reached, a junction has reached its initial saturation point, highlighting how the

junction would perform above this saturation point with signals installed. Analysis showed

maximum queues of 76 passenger car units (PCU) predicted in the northbound direction, which

equates to approximately 230m in length.

7.2.3 PM peak statistics show that signalisation of the junction would cause a queue of 273 PCU

(approximately 819m in length), with a maximum saturation of 694% possible in the northbound

direction. This further corroborates that signalising the existing junction would have an extremely

negative impact on road users, with high junction saturation and long queues. From this analysis,

results were unanimous in the fact that signalising the existing junction would have detrimental

effects on queuing and would cause additional strain to the network at this location. Therefore,

this option has not been included within remedial measures below.



7.2.4 Cost of land has been estimated using historic scheme statistics, and it is recommended a District

Valuer is contacted to properly appraise the worth of the land. SPONS rates have been used to

estimate the predicted cost of construction for each option.

7.2.5 Based on the assumptions outlined and the extent of further investigation required for remedial

measures, as stated above, cost ranges provided are approximate and have been included to

provide some insight to initial estimations based on preliminary desktop studies. Cost rankings

are likely to remain consistent even with fluctuations in design and construction required.

However, overall final costs are likely to vary based on the need for a detailed geotechnical

investigation to finalise earthworks required, fluctuations in land value and in-depth analysis into

the optimal vertical and horizontal alignment of the proposed measures must be carried out. This

is predominantly applicable for Options 2 and 3.

7.2.6 Calculations to determine the capacity of the roundabout can be found in Appendix E.



Table 7-1 – Reviewed remedial measures

Option Description Reason Advantages Disadvantages Cost

1A • Prohibiting left

turns exiting

minor roads.

• Swept path analysis and conflict

study results show encroaching

the northbound carriageway is

extremely likely for cars turning

left from the A703, and

therefore inevitable for any

larger vehicles due to the angle

of the junction and width of

carriageway.

• Mitigates encroachment of

oncoming carriageway when

turning left.

• Reduces potential of head on

collisions with mainline traffic

travelling northbound.

• Additional trip generation at other

locations - particularly north of the

junction. Approximately 3-6 minutes

additional journey time estimated

from INREX.

• Road users may continue to make left

turn manoeuvre.

• Poor visibility remains, predominantly

looking left from minor routes

(specifically the A703).

• More right turn manoeuvres

encouraged.

• Level of provision does not equate to

traffic flows at the junction.

£15,000 -

£30,000

1B • One-Way

System (Junction

in – A703 /

Junction out –

Old Pentland

Road).

• Visibility of the A702 from the

A703 is poor and does not meet

standards, particularly for minor

road users looking southbound.

This is due to road alignment of

the main carriageway.

• Limits number of manoeuvres

possible, reducing potential

conflicts.

• Prevention of junction priority

confusion which occurred during

site visits.





from INREX.

£15,000 -

£30,000



• Better visibility for road users

approaching the A702 from Old

Pentland Road – increased visibility

looking southbound when

compared to available visibility

from the A703.

• Reduction in road users

encroaching the minor road

oncoming traffic lane when turning

right into the junctions from the

A702. This was observed during

the conflict study.

• Preventing traffic turning into Old

Pentland Road from the A702 will

eradicate gaps in the traffic flow

currently provided for users turning

right on to the A702. This is since road

users travelling south will now turn

into the A703 only, so no traffic is

slowing prior to turn into Old Pentland

Road. This will increase the difficulty

in turning right from the minor road

(A703) on to the mainline

carriageway.



• Previously discussed and discounted

by Midlothian Council.

1C • Prohibition of

right turn from

A702 on to minor

roads.

• This manoeuvre was associated

with three of the seven

collisions recorded within a five-

year period (2014-2018),

discussed in Section 3.4.

• Reduction in potential for head on

collisions to occur.

• Limits number of manoeuvres

possible, reducing potential

conflicts.

• Reduction in road users

encroaching the minor road





from INREX.



£15,000 -

£30,000



oncoming traffic lane when turning

right into the junctions from the

A702. This was observed during

the conflict study.

• Road users may continue to make

right turn manoeuvre.

• Eradication of gaps in the northbound

A702 traffic, which will result in more

difficulty for road users joining the

A702 from minor roads.

2A • Partial closure

and realignment

of the A703.

New junction to

be created, with

Old Pentland

Road traffic

joining the

realigned A703.

• Junction to be

signalised.

• Visibility from the minor

junctions is poor, particularly

looking southbound. Junction

layout is known to cause

priority confusion, and

alignment of the A703 to the

A702 is almost parallel.

• Level of provision currently

available at the junction does

not equate to traffic flows –

this would upgrade the

junction such that is would fall

under the category ‘Other

junction type’.

• Simplification of junction layout,

which is currently known to cause

road user confusion.

• Improved forward visibility looking

southbound from the new

proposed A703 junction to the

A702.

• Controlled traffic movement,

preventing drivers misjudging gap

sizes.

• Realignment of the A703 with

larger radii, increasing visibility on

the minor road and improving

sight stopping distances.

• Alignment location ensures no

proximity to existing private

buildings.

• Land acquisition required (approx.

20,000m2).

• Increased journey time for users on

the local access section of the A703.

• Earthworks and regrading of land –

geotechnical investigation required.

• Increased traffic flows to the new

junction.

• Departures required for horizontal

and vertical alignment.

• Relocation of existing carrier poles on

Old Pentland Road required.

• New access roads required for Old

Pentland Road private property.

• Potential delays and queuing – full

LINSIGG model required.

£4 – £6

million



• Private access A703 to be utilised

by non-motorised users.

• Inadequate sight stopping distance

for A702 northbound traffic without

additional road alterations.

• Possibility of increase in rear end

shunts.

2B • Realignment of

the A703. New

junction to be

signalised.

• Old Pentland

Road to be used

as existing. Right

turn ghost island

to be

constructed.

• Visibility from the minor

junctions is poor, particularly

looking southbound. Junction

layout is known to cause

priority confusion, and

alignment of the A703 to the

A702 is almost parallel.







junction type’.

• Simplification of junction layout,

which is currently known to cause

road user confusion.

• Improved forward visibility looking

southbound from the new

proposed A703 junction to the

A702.

• Controlled traffic movement,

preventing drivers misjudging gap

sizes.


10,000m2).

• Increased journey time for users on

the local access section of the A703.

• Extensive earthworks and regrading

of land – geotechnical investigation

required.

• Departures required for horizontal

and vertical alignment.

• Potential delays and queuing – full

LINSIGG model required.


shunts.

• Relocation of A703 traffic flows may

result in limited gaps at Old Pentland

Road for users to join the A702.

£3 - £5

million



3A • Roundabout to

be located in the

vicinity of the

existing junction.

• Old Pentland

Road users to

join A703.





junction such that it would fall


junction type’.

• Junction capacity able to

accommodate traffic flows.

• Reduction in potential conflicts

due to new road layout, which will

also remove any priority

confusion.

• Realignment of A702 south

removes current visibility issues

on the approach to the existing

junction and removes several

bends with tight radii from the

mainline.

• Alignment location ensures no

proximity to existing private

buildings.


35000m2).

• Encroachment of private property to

realign A702 south.

• Regrading of land due to 1:8 slope

(approximate) to accommodate

proposed layout required –

extensive geotechnical investigation

required.

• Increased traffic flows to the A703

due to closure of Old Pentland Road.

• Departures likely required due to

vertical and horizontal alignment

proposed road alterations.


shunts.

£8 – £11

million

3B • Roundabout to

be located at

realigned A703.

• Old Pentland

Road to be used






• Junction capacity able to

accommodate traffic flows.

• Reduction in potential conflicts

due to new road layout, which will


25000m2).

• Regrading of land due to 1:14 slope

(approximate) to accommodate

proposed layout required –

£6 – £8

million



as existing.

Right turn ghost

island to be

constructed.

under the category roundabout

(or other type).

also remove any priority

confusion.

• Realignment of A702 and A703

removes current visibility issues

on the approach to the existing

junction and removes several

bends with tight radii from the

mainline.

• Old Pentland Road to function as

before, no increased traffic flows

to the A703

extensive geotechnical investigation

required.

• Departures likely required due to

vertical and horizontal alignment

proposed road alterations.


shunts.



8 Conclusions and Recommendations

8.1.1 An assessment of the existing junction layout has been carried out to highlight any existing issues

based on the frequency and similarity in collisions that have occurred.

8.1.2 It was found that the existing layout is not to current standards, and the available capacity cannot

cope with the current level of traffic demand from the minor roads the junction currently

undergoes. Previous remedial measures at this junction have attempted to address this problem,

including the reduction of the southbound carriageway to one lane. However, a collision problem

still exists and with the new developments proposed in the vicinity of the junction, an increase in

trip generation is to be expected.

8.1.3 Existing provisions for non-motorised users is poor in the vicinity of the junction, with footways

below current standard provided. However, the increase in approved developments will result in

an increase in trip generation of not only road users but pedestrians and cyclists as well.

Therefore, further improvements and investigations will be required to ensure the safety of non-

motorised users as well.

8.1.4 Collision analysis determined that collisions were commonly caused by human error. Turning right

into the minor junction, assumed to be the A703 based on collision data available, attributed to

three collisions associated with the junction. Although contributory factors did not cite road layout

as an issue, it is possible that a combination of the layout, traffic flow and driver decisions

impacted on the number of collisions occurring.

8.1.5 Conclusions from the conflict study further highlight the benefits that would be occur from

remedial measures at this junction. No serious conflicts occurred, however, the high level of near-

miss conflicts and the projected increase in traffic flow gives rise to a higher potential for future

collisions.

8.1.6 From investigation, seven remedial options have been reviewed, ranging from implementing

TROs, adding additional signage to alterations of the existing road layout. Minor roads are the

responsibility of Midlothian Council. Therefore, agreement between Transport Scotland and

Midlothian Council concerning future improvements and options that can be implemented to this

junction must be sought. Remedial measures reviewed, alongside estimated costs are shown in

Table 8-1.

8.1.7 Signalisation of the junction using the existing layout was also considered. However, it was

concluded through modelling this proposal in Linsig that this would cause queues up to 274 PCU

and would result in high levels of junction saturation. Due to these issues, the measure was

discounted and has not been considered further or alongside other remedial measures.



Table 8-1 – Remedial measures and costs

8.1.8 Advantages and disadvantages outlined in Section 7 should be considered when establishing the

optimal solution. Within the study area, only the A702 is part of the South East Trunk Road Unit,

with Midlothian Council being responsible for the A703 and Old Pentland Road. Therefore, liaison

with Midlothian Council and further investigation of potential remedial measures outlined will be

essential to ensure a collaborative solution is agreed upon.

8.1.9 The investigatory nature of this report results in the provision of approximate values for long term

options since specific volumes and quantities and detailed scope of works are not known. Land

and property costs have been estimated using available data sources for other schemes, and it is

recommended that for more detailed information, District Valuer Services are utilised. Since costs

are indicative and should only be used as an initial value, no economic justification has been

provided at present.

Option Measure Estimated Cost

1A TRO - Prohibiting left turns exiting minor roads. £15,000 - £30,000

1B TRO - One-Way System (Junction in – A703 / Junction out – Old Pentland

Road).

£15,000 - £30,000

1C TRO - Prohibition of right turn from A702 on to minor roads. £15,000 - £30,000

2A Realignment of A703. Closure of Old Pentland Road junction. New

signalised junction to be constructed in vicinity of existing junction.

£4 – £6 million

2B

Closure of existing A703 junction, realignment and signalisation of new A703

junction south of existing. Old Pentland Road to remain as existing with

addition of right turn ghost island.

£3 - £5 million

3A

Connection of Old Pentland Road to A703 and construction of roundabout

in the vicinity of existing junction. Realignment of A702 south of proposed

roundabout.

£8 – £11 million

3B

Closure of existing A703 junction, realignment and roundabout construction

using the new A703 alignment. Old Pentland Road to remain as existing

with addition of right turn ghost island.

£6 – £8 million


Doc. Ref.:18/SE/0801/019 /001 - A.1 - Issued: February 2020

Appendix A Collision Stick Diagrams

V2

V1

V

V2

V2

V1

V2

V1

V1

V2 V1

V2

V1

V2


Doc. Ref.:18/SE/0801/019 /001 - B.1 - Issued: February 2020

Appendix B Design Speed Calculations for A702


Doc. Ref.:18/SE/0801/019 /001 - B.2 - Issued: February 2020


Doc. Ref.:18/SE/0801/019 /001 - C.1 - Issued: February 2020

Appendix C Camera Locations for Conflict Study


Doc. Ref.:18/SE/0801/019 /001 - C.2 - Issued: February 2020


Doc. Ref.:18/SE/0801/019 /001 - D.1 - Issued: February 2020

Appendix D Remedial Options


Doc. Ref.:18/SE/0801/019 /001 - E.1 - Issued: February 2020

Appendix E Roundabout Capacity Calculations

project name - scottish government...project name scottish trunk road network south east unit...

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