accident and speed analysis evidence base 7 march 2013
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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

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Presentation Transcript
presentation purpose
Presentation Purpose
  • To provide a summary of the accident analysis and review of vehicle speeds and speed enforcement on the route
  • All supporting reports and analysis to be circulated in due course to group members for more detailed consideration
presentation contents
Presentation Contents
  • Route Overview
  • Accident Analysis
  • Speed Analysis
  • Current Speed Enforcement
  • Next Steps / Further Considerations
route overview
Route Overview
  • Route serving a mix of local and strategic traffic movements, connecting major conurbations and serving smaller towns
  • Critical link between the Central Belt and the North
  • Mix of dual with at grade junctions, single, WS2+1 and dual route provisions
route overview traffic volumes
Route Overview – Traffic Volumes
  • Indicative Annual Average Daily Traffic Flows (2012)
route overview traffic volumes1
Route Overview – Traffic Volumes
  • Noticeable seasonal variation in traffic flows on the route (example at Dunkeld below)
accident analysis approach
Accident Analysis Approach
  • Route split into three distinct parts
  • STATS19 analysis (2007 to 2011)
  • Comparisons made against wider trunk road averages
  • Consideration 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 themes
  • More detailed review of police report for all fatal accidents
  • Targeted analysis by section (acc rate and KSI rate)
  • Identification of cluster locations to capture localised issues
a9 dunblane to perth summary statistics
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
a9 dunblane to perth key safety themes
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)
a9 dunblane to perth fatal accident analysis
A9 Dunblane to Perth – Fatal Accident Analysis
  • 4 out of 8 fatal accidents occurred at a junction
  • 3 out of 8 fatal accidents involved HGVs (1 accident with HGV>7.5T)
  • Only 1 of the fatal accidents was a single vehicle accident
a9 dunblane to perth section analysis
A9 Dunblane to Perth–Section Analysis
  • Two 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 area
      • Proposal under consideration as part of on-going SRS work to improve roadside safety
a9 dunblane to perth cluster identification
A9 Dunblane to Perth – Cluster Identification
  • 14 cluster sites identified with concentration of accidents
  • 10 of these sites have previously been identified / investigated / treated
  • Remaining 4 cluster sites be programmed for investigation and analysis for common causations
    • Auchterarder Bypass
    • Balhaldie Services
    • Crieff Road
    • Inveralmond Roundabout
a9 inverness tore to scrabster summary statistics
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 volumes
  • KSI Ratio is less than the trunk road national average (0.20 v 0.24)
  • Annual accident levels declining
a9 inverness tore to scrabster key safety themes
A9 Inverness (Tore) to Scrabster – Key Safety Themes
  • ‘Turning 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 accidents
  • 43% of accidents occurred at a junction (compared to 26% NW unit average)
a9 inverness tore to scrabster fatal accident analysis
A9 Inverness (Tore) to Scrabster – Fatal Accident Analysis
  • 9 fatal accidents (3 south and 6 north of Dornoch Bridge)
  • 50% of fatals north of Dornoch Bridge were due to ‘loss of control’
  • 3 out of 5 fatals north of Dornoch Bridge were single vehicle
a9 inverness to scrabster cluster identification
A9 Inverness to Scrabster – Cluster Identification
  • 9 cluster sites identified
  • 6 sites addressed / being addressed through safety improvements
  • 1 investigation identified no treatable common factors
  • 2 sites currently under more detailed investigation
    • Drummond Junction
    • Dunrobin Castle Junction
a9 perth to inverness tore overview
A9 Perth to Inverness (Tore) - Overview
  • Varying route provision requires analysis by route type
  • Single carriageway makes up 65% of the route length
  • 68% all accidents occurred on single carriageways
  • 77% of all KSI accidents occurred on single carriageways
  • Single carriageway KSI ratio (0.32) > trunk road national av. (0.24)
a9 perth to inverness tore key themes
A9 Perth to Inverness (Tore) – Key Themes
  • HGV>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 carriageways
  • Goods vehicles<7.5T involved in 13.6% of accidents on single carriageways (compared to NW unit average of 7.0%)
a9 perth to inverness tore key themes1
A9 Perth to Inverness (Tore) – Key Themes
  • Similar contributory factors are higher than the NW unit average on single and dual route types
  • However ‘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)
a9 perth to inverness tore fatal accident analysis
A9 Perth to Inverness (Tore) – Fatal Accident Analysis
  • 25 out of 31 fatal accidents occurred on single carriageways
  • HGVs>7.5T involved in 23% of fatal accidents
a9 perth to inverness tore fatal accident analysis1
A9 Perth to Inverness (Tore) – Fatal Accident Analysis
  • ‘Overtaking’, ‘moved out of lane’ and ‘loss of control’ the most common causes of fatal accidents
  • Only 1 overtaking accident involved an HGV>7.5T
a9 perth to inverness tore section analysis
A9 Perth to Inverness (Tore) – Section Analysis
  • 3 out of 25 route sections were identified to have an accident rate higher than the national average
    • Bankfoot (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
a9 perth to inverness cluster identification
A9 Perth to Inverness – Cluster Identification
  • 9 cluster sites identified
  • 6 sites addressed / being addressed through safety improvements
  • 1 site investigated but no works taken forward (Munclochy Junction)
  • 1 site investigated but no treatable common factors identified
  • 1 site currently under more detailed investigation
    • Granish (A95) Junction
a9 summary of vehicle speeds approach
A9 Summary of Vehicle Speeds - Approach
  • Speed data by vehicle class collected at 10 SRTBd counter locations across the route
  • Summary of data from full neutral months in 2012
  • Data summarised by speed bins, by hour, max speed to be used to inform existing speed enforcement regime
a9 vehicle speed summary average speeds
A9 Vehicle Speed Summary – Average Speeds
  • Evidence of vehicles travelling above the posted speed limit at every counter location interrogated
  • Most pronounced for HGVs>7.5Ts

* Approximate value

a9 current speed enforcement 2012
A9 Current Speed Enforcement (2012)
  • Speed Enforcement by Northern, Tayside and Central Police and Safety Camera Partnerships (SCPs)
  • Police enforcement through patrols on the route
  • SCP enforcement through 5 Fixed Safety Cameras
    • Dunblane to Perth (3)
    • Perth to Inverness (2)
  • And widespread mobile enforcement (109 sites) across the entire route
a9 current safety camera deployment
A9 Current Safety Camera Deployment
  • Fixed cameras had an average of 0.1 offences per hour in 2012
  • SCPs deployed mobile enforcement on the A9 for a total of approximately 1,500 hours in 2012
a9 existing speed enforcement regime
A9 Existing Speed Enforcement Regime
  • Speed enforcement undertaken through a collection of fixed sites, mobile sites and police patrols
  • Higher offence rates recorded south of Inverness
  • Offenders typically reside across Scotland\'s key areas of population
a9 evidence base summary
A9 Evidence Base Summary
  • Accident Analysis
  • Dunblane to Perth
  • High severity of accidents at junctions
  • High number of single vehicle, roadside strike accidents in the Gleneagles area
  • Inverness to Scrabster
  • High number of accidents at junctions
  • High proportion of fatal accidents north of Dornoch Bridge single vehicle and due to loss of control
a9 evidence base summary1
A9 Evidence Base Summary
  • Perth to Inverness
  • High number of HGV>7.5Ts in accidents, particularly on single carriageways
  • Fatigue contributing to accidents is more common on single carriageway sections
  • Sudden braking contributing to accidents is more common on dual carriageway sections
  • Vast majority of fatal accidents occurred on single carriageways
  • Overtaking, moved out of lane and loss of control most common manoeuvres in fatal accidents
a9 evidence base summary2
A9 Evidence Base Summary
  • Vehicle Speeds
  • Evidence of a significant proportion of vehicles exceeding the posted speed limit
  • Speed Enforcement
  • Highest offence rates recorded south of Inverness
next steps
Next Steps……
  • Discuss key outcomes
  • Reach outline consensus on issues
  • Circulate supporting reports
  • Identify appropriate measures
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