Traffic Assessment
Proposed Extension of Gravel Extraction
at Gravel Pit Road, Nook
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Traffic Assessment – Prosed Extension of Gravel Extraction at Gravel Pit Road, Nook 2
By Terry Eaton
C O N T E N T S
Page
1. INTRODUCTION..........................................................3
2. THE SITE.....................................................................3
3. THE PROPOSAL .........................................................4
4. ROAD FACILITIES.......................................................4
5. TRAFFIC DATA ...........................................................7
6. ASSESSMENT.............................................................8
7. CONCLUSION ...........................................................10
Traffic Assessment – Prosed Extension of Gravel Extraction at Gravel Pit Road, Nook 3
By Terry Eaton
1. Introduction
This report is provided as an assessment of the traffic impact for the
extension of the existing gravel extraction activity at AG & BJ Riley’s
quarry, Gravel Pit Road, Nook.
Preparation of this report has included a site visit and discussion with
the quarry operator.
2. The Site
The site is the existing gravel pit located off the end of Gravel Pit Road
some 1.5 kilometres from the Nook Road junction. Indications are that
the public section of Gravel Pit Road extends some 900 metres from
Nook Road with the remaining distance to the pit as a private gravel
access road.
The present quarry activities are based on contractor demand for
materials with the site operation to win, sieve and stockpile materials
ready for cartage, 4 employees are normally engaged in this process.
Cartage is generally batched with cartage at some 2,000 tonnes per
week with average orders of some 4,000 tonnes, i.e. cartage over 2
week periods.
Land uses in proximity are generally rural with the quarry in a forested
area with abutting rural land in use for grazing with a major sheep
export holding area on the south side near the gateway to the Quarry.
The loading facilities at the sheep holding pens are set back from
Grave Pit Road such that truck manoeuvring at this site is away from
the Gravel Pit Road carriageway. Closer to Nook Road is a Boral
Quarry site with activities on both sides of Gravel Pit Road with the
road crossing controlled by “Give Way” signs to maintain priority on
Gravel Pit Road. It is understood that the cartage from this site is
similar to the AG & BJ Riley demand of some 2,000 tonnes per week.
Traffic Assessment – Prosed Extension of Gravel Extraction at Gravel Pit Road, Nook 4
By Terry Eaton
3. The Proposal
The proposal is to extend the present quarry activities for another 15 to
20 years with production to some 50,000 to 60,000 tonnes/annum.
Indications are the quarry activity will generally be as per the existing
rate with the present employees and cartage up to some 2,000 tonne
per week.
4. Road Facilities
•••• Gravel Pit Road
This road could be classified as a dead-end local rural access
road serving local agriculture needs and the quarry activities.
The road is constructed for its public length of some 900 metres
with a minimum width of some 4.5 metres with widening up to
some 6.5 metres at corners and crests with formed shoulders and
grass verges. Some 100 metres from Nook Road there is a short
narrow section due to a road edge failure at a culvert.
Generally, the road standard could be considered adequate for
use by heavy cartage vehicles, particularly as there is no external
through traffic using the road with almost all use seen as relating
to the roadside commercial activities.
Washed out area
Traffic Assessment – Prosed Extension of Gravel Extraction at Gravel Pit Road, Nook 5
By Terry Eaton
The road profile is undulating and as a downgrade to Nook Road.
The alignment is generally as two straight sections joined by a
tight curve (some 80 metres radius) at the Boral site.
The road standard is seen as limiting travel speed to some 55 to
65 km/h.
Traffic accident information indicates no reported accidents on
this road for the last 5 years.
•••• Nook Road
This road provides a rural collector link between Sheffield Main
Road at Acacia Hills via Nook to Sheffield.
The road could be considered as a Category V road within the
Kentish Planning Scheme’s Road and Rail Asset Code, with the
primary purpose to provide access to rural properties with a
significant through traffic component.
The road is constructed with a sealed pavement some 6.0 metres
wide, gravel shoulders some 1.0 metres wide, side swale drains
and grass verges. Additional pavement width is provided at tight
curves to accommodate the swept path of semi-trailers.
The road alignment is a series of straights and relatively tight
curves with steep hill sections either side of the ridge at Gravel
Pit Road. The road between Gravel Pit Road and Sheffield Road
is considered of a high standard for the use and the terrain.
Hill section
Traffic Assessment – Prosed Extension of Gravel Extraction at Gravel Pit Road, Nook 6
By Terry Eaton
The road standard is seen as limiting travel speed to some 70 to
75 km/h in proximity to Gravel Pit Road.
Accident records indicate 10 accidents for the 3.3 kilometre
section from Sheffield Main Road to Gravel Pit Road for the last 5
years. The link accidents included 1 serious accident, 4 minor
accidents and 3 property damage with 2 serious accidents
recorded for the Sheffield Main Road/Nook Road junction.
•••• Nook Road/Gravel Pit Road Junction
This junction is near a crest on Nook Road and is constructed
with a short section of seal on the Gravel Pit Road approach.
A minor forest access road is located opposite Gravel Pit Road.
The throat length at the edge of the through carriageway is
widened to some 120 metres, with some 80 metres on the
approach and 40 metres on the departure to/from the centreline of
Gravel Pit Road the additional areas provide for left turn
approach/departure tapers.
The gradient on Nook Road past the junction is an upgrade from
North to South of some 4% with a downgrade of some 8% north
of the junction.
Sight distance at the Gravel Pit Road junction is some 175 metres
to the north and some 165 metres to the south. The sight distance
to the north does rely on maintaining tree/shrub clearance within
the site triangle.
Traffic accident information indicates no accidents at this junction
in the last 5 years.
View to south View to north
Traffic Assessment – Prosed Extension of Gravel Extraction at Gravel Pit Road, Nook 7
By Terry Eaton
5. Traffic Data
•••• Nook Road
Traffic information indicates a volume of some 900 vehicles per
day on Nook Road near Sheffield Road. Allowance for traffic
growth at some 2% per annum suggests a year 2028 value of
some 1,550 vehicles per day. For assessment the peak hours
are provided for at 12% of the ADT with 70/30 split with the major
value for traffic toward Sheffield Road for the morning and the
reverse for the evening.
•••• Gravel Pit Road
Light vehicle use on this road relates to the commercial activities
and is likely to be less than 40 vehicles per day. For the
commercial uses the following estimates are provided:
Annual
No. Loaded Trips
Estimated Peak Day Volume
(two-way)
Gravel Pit (Riley)
60,000 tonne
2,400 40
Fine Crushed Rock (Boral)
60,000 tonne
2,400 40
Sheep transport
60,000 300 * 80
Total 5,100 160
* volume in/out of holding area
Addition of the peak day heavy and light vehicles suggests a peak
ADT of some 200 vehicles with some 80% as heavy vehicles.
Traffic Assessment – Prosed Extension of Gravel Extraction at Gravel Pit Road, Nook 8
By Terry Eaton
6. Assessment
6.1 Road Safety
•••• Nook Road
The assessment is that this road is satisfactory to cater for
the cartage of materials from Gravel Pit Road.
An assessment of the accident history based on the Traffic
Authority of New South Wales’ average accident rate for
main rural roads of 0.49 accidents per million vehicle
kilometres of travel indicates a critical accident rate of 1.48
accidents per million vehicle kilometres for the section from
Gravel Pit Road to Sheffield Road. The actual rate of 1.33
accidents per million vehicle kilometres is less than this
critical value indicating an acceptable level of safety safe .
•••• Gravel Pit Road
In view of the use of this road by traffic generally local to the
conditions with no through traffic the road standard is
considered satisfactory provided the surface is maintained
and any emerging road hazards are addressed. With regard
to hazard the site visit found a short section of road near the
Nook Road junction where a culvert wash out has reduced
the road width at a low point (sag curve). The road is on an
embankment with the risk of further edge failure. Remedial
measures such as extension of the culvert, pavement
widening and consideration for installation of edge protection
are considered prudent improvements.
•••• Nook Road/Gravel Pit Road Junction
The available sight distance at this junction, minimum value
165 metres to the south, meets DIER requirements for an
approach speed of some 75km/h. The available sight
distances also meets truck stopping distance for approach
speeds of some 75km/h for the approach from the south and
some 100km/h for the approach from the north. Truck
stopping distance is considered the minimum standard to be
met with the available sight distance to the south considered
Traffic Assessment – Prosed Extension of Gravel Extraction at Gravel Pit Road, Nook 9
By Terry Eaton
consistent with the speed environment for the location. The
sight distance to the north is well in excess of truck stopping
distance due to the steep gradient.
Consideration could be given to the following measures:
(i) Maintain the sight triangle to the north by
keeping the area clear of shrubs and trees.
(ii) Installation of a W5-22 (B size) truck
warning sign with attached “Turning Traffic”
plate some 100 metres prior to Gravel Pit
Road for both approaches. These signs will
increase awareness of the truck
movements.
6.2 Traffic Service
•••• Nook Road/Gravel Pit Road Junction
The predicted peak hour traffic volumes indicate a high level
of service will be available for vehicles exiting Gravel Pit
Road with the practical absorption capacity for right turns
from Gravel Pit Road at some 400 vehicles per hour (gap
time 8 seconds and 5 second move up time – typical for
truck movements).
75
125
5
15
2028 Evening Peak Hour
Gravel Pit Road
Nook Road
Traffic Assessment – Prosed Extension of Gravel Extraction at Gravel Pit Road, Nook 10
By Terry Eaton
Comparison between the actual predicted turn volume of
15 vehicles and the practical absorption value of
400 vehicles is indicative that a high level of service will be
available.
•••• Nook Road
The predicted peak hour flow of some 200 vehicles per hour
suggests a nominal level of service “C” value for Nook Road
with a lower service level for the hill section. However, the
use of Nook Road by heavy vehicles is seen as consistent
with the road classification as a rural collector.
•••• Gravel Pit Road
The road standard with remedial repair work at the culvert
near Nook Road is considered satisfactory for the predicted
traffic volume of up to 200 vehicles per day.
The gravel surface is considered adequate particularly as the
use is generally by heavy vehicles and as there are no
residences close to the roadway, i.e. no dust nuisance issues.
7. Conclusion
A traffic assessment for extension of the AG & BJ Riley’s Gravel Pit
operations at Gravel Pit Road, Nook, indicates no significant traffic
safety or traffic service issues provided some road repairs including
pavement widening with consideration for edge protection at the
culvert on Gravel Pit Road near Nook Road are advanced. It is also
considered prudent to keep the sight triangle to the north of the Nook
Rd / Gravel Pit Rd. junction clear and install “Truck Entering” warning
signs on Nook Road either side of this junction.
Terry Eaton