a9 safety group
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Accident and Speed Analysis - Evidence Base 7 March 2013. A9 Safety Group. Presentation Purpose. To provide a summary of the accident analysis and review of vehicle speeds and speed enforcement on the route - PowerPoint PPT PresentationTRANSCRIPT
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A9 Safety GroupAccident and Speed Analysis - Evidence Base7 March 2013
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Presentation PurposeTo provide a summary of the accident analysis and review of vehicle speeds and speed enforcement on the routeAll supporting reports and analysis to be circulated in due course to group members for more detailed consideration
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Presentation ContentsRoute OverviewAccident Analysis Speed AnalysisCurrent Speed EnforcementNext Steps / Further Considerations
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Route OverviewRoute serving a mix of local and strategic traffic movements, connecting major conurbations and serving smaller townsCritical link between the Central Belt and the NorthMix of dual with at grade junctions, single, WS2+1 and dual route provisions
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Route Overview Traffic VolumesIndicative Annual Average Daily Traffic Flows (2012)
SectionAADT% By Vehicle ClassCarPSVMcycleLGV / HGV7.5TDunblane to Perth25,00081.8%0.4%0.4%9.0%8.4%Perth to Luncarty22,50087.7%0.6%0.7%6.9%4.0%Luncarty to Pitlochry13,50078.7%0.6%1.4%12.4%6.9%Pitlochry to Inches8,50077.3%0.8%0.4%14.1%7.4%Inches to Raigmore26,500Raigmore to Longman37,500Longman to Dornoch6,00089.2%0.7%0.5%7.1%2.5%Dornoch to Scrabster2,500
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Route Overview Traffic VolumesNoticeable seasonal variation in traffic flows on the route (example at Dunkeld below)
Chart1
8604
10773
11991
14210
14629
15008
14603
15696
13886
14673
12021
8312
AADT
Sheet1
AADT
January8604
February10773
March11991
April14210
May14629
June15008
July14603
August15696
September13886
October14673
November12021
December8312
Data from site just south of Dunkeld (JTC00305) from 2010
To resize chart data range, drag lower right corner of range.
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Accident Analysis ApproachRoute split into three distinct partsSTATS19 analysis (2007 to 2011)Comparisons made against wider trunk road averagesConsideration made to standard STATS19 indicators (vehicle type, manoeuvre, weather / lighting conditions, road surface, driver age, driver postcode, time of day etc)Route wide approach to identify key themesMore detailed review of police report for all fatal accidentsTargeted analysis by section (acc rate and KSI rate)Identification of cluster locations to capture localised issues
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A9 Dunblane to Perth Summary Statistics Accident Rate comparable with trunk road national average KSI Ratio marginally higher than trunk road national average (0.26 v 0.24)Annual accident levels declining
Route TypeSlightSeriousFatalTotalKSI RatioDual1424281920.26National Av.0.24
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A9 Dunblane to Perth Key Safety Themes Higher number of HGV>7.5Ts involved in accidents (17% v 9% NE unit average) 53% of right turn accidents are KSIs (compared to 29% NE unit average)
Chart1
0.020.03
0.050.09
0.030.02
0.030.02
0.130.12
0.170.09
A9
NE Unit
Sheet1
Dunblane to Perth
VEHICLE TYPE
A9NE Unit
Pedal Cycle0.020.03
Motorcycle0.050.09
PSV0.030.02
Agricultural0.030.02To resize chart data range, drag lower right corner of range.
GV7.5T0.170.09
1.22.1
47.2
21.8
21.4
9.99.5
12.76.9
0.0120.021
0.040.072
0.020.018
0.020.014
0.0990.095
0.1270.069
Going Ahead74012417163%714291342184261%
Changing Lane1011124%617811043%Changing Lane4%3%
Overtaking037104%2351051425%Overtaking4%5%
Turning Left01452%01455692%Turning Left2%2%
Turning Right469197%15692022869%Turning Right7%9%
Waiting to go ahead03262911%0251982237%Waiting to go ahead11%7%
Moving019104%012911033%Moving4%3%
Parked20241%31027401%Parked1%1%
Slowing / Stopping0110114%2241852117%Slowing / Stopping4%7%
Chart1
0.060.05
0.050.07
0.030.03
0.10.13
0.150.1
0.050.05
0.020.02
0.060.1
A9
NE Unit
Sheet1
A9NE Unit
Changing Lane6%5%
Overtaking5%7%
Turning Left3%3%
Turning Right10%13%
Waiting to go ahead15%10%
Moving Off5%5%
Parked2%2%
Stopping6%10%
To resize chart data range, drag lower right corner of range.
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A9 Dunblane to Perth Fatal Accident Analysis4 out of 8 fatal accidents occurred at a junction3 out of 8 fatal accidents involved HGVs (1 accident with HGV>7.5T)Only 1 of the fatal accidents was a single vehicle accident
Manoeuvre / CausationNumber% of TotalJunction Manoeuvre450%Illness / Disability112.5%Pedestrian Impaired by Alcohol112.5%Loss of Control112.5%Failed to Look112.5%
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A9 Dunblane to Perth Section AnalysisTwo section accident rates are higher than the national average (7.7pia/100mvk)
Dunblane to Greenloaning (8.8pia/100mvk)Influence of accidents in 2007
Blackford to Shinafoot (11.8pia/100mvk)Over 50% of accidents were single vehicle (35% on wider route and NE unit)56% of accidents involved roadside strikes (31% route average, 35% NE unit average) and the majority occurred in the Gleneagles areaProposal under consideration as part of on-going SRS work to improve roadside safety
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A9 Dunblane to Perth Cluster Identification14 cluster sites identified with concentration of accidents10 of these sites have previously been identified / investigated / treatedRemaining 4 cluster sites be programmed for investigation and analysis for common causationsAuchterarder BypassBalhaldie ServicesCrieff RoadInveralmond Roundabout
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A9 Inverness (Tore) to Scrabster Summary Statistics Accident rate is higher than the trunk road national average (24.3 v 18.7 pia/100mvk)But lower accident frequency due to lower traffic volumesKSI Ratio is less than the trunk road national average (0.20 v 0.24)Annual accident levels declining
Route TypeSlightSeriousFatalTotalKSI RatioSingle2034192530.20National Av0.24
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A9 Inverness (Tore) to Scrabster Key Safety ThemesTurning right the most common vehicle manoeuvre in accidents (13.5% compared to 6.1% NW unit average)Failed to look properly, failed to judge other persons speed, careless/reckless and poor turn the most common contributory factor in accidents43% of accidents occurred at a junction (compared to 26% NW unit average)
Chart1
0.0990.149
0.0940.144
0.0540.052
0.0630.049
0.0130.012
0.1350.061
0.020.039
A9
NW Unit
Sheet1
A9NW Unit
Left Bend10%15%
Right Bend9%14%
Overtaking5%5%
Stopping6%5%
Turning Left1%1%
Turning Right14%6%
Held Up2%4%
To resize chart data range, drag lower right corner of range.
Chart1
0.1210.086
0.1040.137
0.0940.123
0.0740.055
0.0710.057
0.0610.048
A9
NW Unit
Sheet1
A9NW Unit
Failed to Look12%9%
Loss of Control10%14%
Slippery Road9%12%
Judge Others Speed7%6%
Careless/Reckless7%6%
Poor Turn6%5%
To resize chart data range, drag lower right corner of range.
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A9 Inverness (Tore) to Scrabster Fatal Accident Analysis9 fatal accidents (3 south and 6 north of Dornoch Bridge)50% of fatals north of Dornoch Bridge were due to loss of control3 out of 5 fatals north of Dornoch Bridge were single vehicle
Manoeuvre / CausationSouth of DornochNorth of DornochNumber% TotalNumber% TotalJunction Manoeuvre133.3%Moved over Centre Line133.3%Overtaking133.3%116.7%Loss of Control350%Ped Stepped Out116.7%Wrong Side of Road (Foreign Driver)116.7%
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A9 Inverness to Scrabster Cluster Identification9 cluster sites identified6 sites addressed / being addressed through safety improvements1 investigation identified no treatable common factors2 sites currently under more detailed investigationDrummond JunctionDunrobin Castle Junction
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A9 Perth to Inverness (Tore) - Overview Varying route provision requires analysis by route typeSingle carriageway makes up 65% of the route length68% all accidents occurred on single carriageways 77% of all KSI accidents occurred on single carriagewaysSingle carriageway KSI ratio (0.32) > trunk road national av. (0.24)
Route TypeSlightSeriousFatalTotalKSI Ratio% of Route TotalTotalKSISingle14141252070.3268%77%Dual79146970.2132%23%WS2+110010.00
- A9 Perth to Inverness (Tore) Key ThemesHGV>7.5Ts involved in 12.4% of accidents (compared to the NW unit average of 6.1%)HGV>7.5T involved in 22.8% of accidents on single carriagewaysGoods vehicles
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A9 Perth to Inverness (Tore) Key ThemesSimilar contributory factors are higher than the NW unit average on single and dual route typesHowever fatigue more prevalent on single carriageway sections (4.1% compared to 0.8% on dual and 1.6% NW unit average)And sudden braking more prevalent on dual carriageway sections (6.0% compared to 3.9% on single and 4.0% NW unit average)
Chart1
0.0810.055
0.0550.027
0.0470.026
0.0410.016
A9 Single
NW Unit
Sheet1
Perth to Inverness
VEHICLE TYPE
A9 SingleNW Unit
Failed to Judge Others Path/Speed0.0810.055
Swerved0.0550.027
Following Too Close0.0470.026
Fatigue0.0410.016To resize chart data range, drag lower right corner of range.
1.22.1
47.2
21.8
21.4
9.99.5
12.76.9
0.0120.021
0.040.072
0.020.018
0.020.014
0.0990.095
0.1270.069
Going Ahead74012417163%714291342184261%
Changing Lane1011124%617811043%Changing Lane4%3%
Overtaking037104%2351051425%Overtaking4%5%
Turning Left01452%01455692%Turning Left2%2%
Turning Right469197%15692022869%Turning Right7%9%
Waiting to go ahead03262911%0251982237%Waiting to go ahead11%7%
Moving019104%012911033%Moving4%3%
Parked20241%31027401%Parked1%1%
Slowing / Stopping0110114%2241852117%Slowing / Stopping4%7%
Chart1
0.0930.055
0.040.027
0.040.026
0.060.04
A9 Dual
NW Unit
Sheet1
Perth to Inverness
VEHICLE TYPE
A9 DualNW Unit
Failed to Judge Others Path/Speed0.0930.055
Swerved0.040.027
Following Too Close0.040.026
Sudden Braking0.060.04To resize chart data range, drag lower right corner of range.
1.22.1
47.2
21.8
21.4
9.99.5
12.76.9
0.0120.021
0.040.072
0.020.018
0.020.014
0.0990.095
0.1270.069
Going Ahead74012417163%714291342184261%
Changing Lane1011124%617811043%Changing Lane4%3%
Overtaking037104%2351051425%Overtaking4%5%
Turning Left01452%01455692%Turning Left2%2%
Turning Right469197%15692022869%Turning Right7%9%
Waiting to go ahead03262911%0251982237%Waiting to go ahead11%7%
Moving019104%012911033%Moving4%3%
Parked20241%31027401%Parked1%1%
Slowing / Stopping0110114%2241852117%Slowing / Stopping4%7%
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A9 Perth to Inverness (Tore) Fatal Accident Analysis25 out of 31 fatal accidents occurred on single carriageways HGVs>7.5T involved in 23% of fatal accidents
Involved Vehicle TypeNumber of Accidents% of TotalCar2271%Goods Vehicles7.5T723%Motorcycle516%PSV310%Other26%Minibus13%
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A9 Perth to Inverness (Tore) Fatal Accident AnalysisOvertaking, moved out of lane and loss of control the most common causes of fatal accidentsOnly 1 overtaking accident involved an HGV>7.5T
Manoeuvre / CausationNumber% of TotalInvolved HGV>7.5TOvertaking825.8%1Moved out of Lane / Drifting722.6%1Loss of Control619.0%0Pedestrian Stepped Out412.9%3Junction Manoeuvre39.7%0Following Too Close39.7%2
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A9 Perth to Inverness (Tore) Section Analysis3 out of 25 route sections were identified to have an accident rate higher than the national averageBankfoot (9.4 pia/100mvk)Faskally (50.9 pia/100mvk)Meall Mor to Kessock Bridge (9.0 pia/100mvk)
Road improvements delivered in 2009/2010 at Bankfoot and Faskally and in 2012/2013 across the Meall Mor to Kessock Bridge section
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A9 Perth to Inverness Cluster Identification9 cluster sites identified6 sites addressed / being addressed through safety improvements1 site investigated but no works taken forward (Munclochy Junction)1 site investigated but no treatable common factors identified1 site currently under more detailed investigationGranish (A95) Junction
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A9 Summary of Vehicle Speeds - ApproachSpeed data by vehicle class collected at 10 SRTBd counter locations across the routeSummary of data from full neutral months in 2012Data summarised by speed bins, by hour, max speed to be used to inform existing speed enforcement regime
LocationCarriageway TypeLuncartySingleMoulinearnDualKilliecrankieSingleDalwhinnieSingleKincraigSingleMoySingleNorth of InveralmondDualGreenloaningDualDunblane BypassDualNorth of AuchterarderDual
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A9 Vehicle Speed Summary Average SpeedsEvidence of vehicles travelling above the posted speed limit at every counter location interrogatedMost pronounced for HGVs>7.5Ts
* Approximate value
Vehicle TypeDunblane to PerthPerth to Inverness SinglePerth to Inverness DualAv Speed (mph)%Above LimitAv Speed(mph)%Above LimitAv Speed(mph)%Above Limit
Cars67.839.7%57.630.2%67.032.1%HGVs>7.5 tonnes53.851.5>95%*53.5>75%*Motorcycles70.150.9%57.929.2%
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A9 Current Speed Enforcement (2012)Speed Enforcement by Northern, Tayside and Central Police and Safety Camera Partnerships (SCPs)Police enforcement through patrols on the routeSCP enforcement through 5 Fixed Safety CamerasDunblane to Perth (3)Perth to Inverness (2)And widespread mobile enforcement (109 sites) across the entire route
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A9 Current Safety Camera DeploymentFixed cameras had an average of 0.1 offences per hour in 2012SCPs deployed mobile enforcement on the A9 for a total of approximately 1,500 hours in 2012
SectionNo of Mob SitesOffencesDeployment HoursOffences / HourFull Route10910,2381,5136.8Dunblane to Perth94,58939511.6Perth to Inverness (Single)524,4917076.4Perth to Inverness (Dual)188342094.0Inverness to Dornoch17189112 1.7Dornoch to Scrabster13135881.5
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A9 Post Code Analysis Offenders
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A9 Existing Speed Enforcement RegimeSpeed enforcement undertaken through a collection of fixed sites, mobile sites and police patrolsHigher offence rates recorded south of InvernessOffenders typically reside across Scotland's key areas of population
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A9 Evidence Base SummaryAccident AnalysisDunblane to PerthHigh severity of accidents at junctionsHigh number of single vehicle, roadside strike accidents in the Gleneagles area
Inverness to ScrabsterHigh number of accidents at junctionsHigh proportion of fatal accidents north of Dornoch Bridge single vehicle and due to loss of control
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A9 Evidence Base SummaryPerth to InvernessHigh number of HGV>7.5Ts in accidents, particularly on single carriagewaysFatigue contributing to accidents is more common on single carriageway sectionsSudden braking contributing to accidents is more common on dual carriageway sectionsVast majority of fatal accidents occurred on single carriagewaysOvertaking, moved out of lane and loss of control most common manoeuvres in fatal accidents
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A9 Evidence Base SummaryVehicle SpeedsEvidence of a significant proportion of vehicles exceeding the posted speed limit
Speed EnforcementHighest offence rates recorded south of Inverness
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Next StepsDiscuss key outcomesReach outline consensus on issuesCirculate supporting reportsIdentify appropriate measures
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A9 Safety GroupAccident and Speed Analysis - Evidence Base7 March 2013
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