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A9 Safety Group

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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A9 Safety Group

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  1. Accident and Speed Analysis - Evidence Base 7 March 2013 A9 Safety Group

  2. 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

  3. Presentation Contents • Route Overview • Accident Analysis • Speed Analysis • Current Speed Enforcement • Next Steps / Further Considerations

  4. 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

  5. Route Overview – Traffic Volumes • Indicative Annual Average Daily Traffic Flows (2012)

  6. Route Overview – Traffic Volumes • Noticeable seasonal variation in traffic flows on the route (example at Dunkeld below)

  7. 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

  8. 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

  9. 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)

  10. 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

  11. 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

  12. 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

  13. 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

  14. 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)

  15. 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

  16. 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

  17. 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)

  18. 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%)

  19. 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)

  20. 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

  21. 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

  22. 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

  23. 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

  24. 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

  25. 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

  26. 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

  27. 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

  28. A9 Post Code Analysis – Offenders

  29. 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

  30. 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

  31. 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

  32. 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

  33. Next Steps…… • Discuss key outcomes • Reach outline consensus on issues • Circulate supporting reports • Identify appropriate measures

  34. Accident and Speed Analysis - Evidence Base 7 March 2013 A9 Safety Group

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