Roadside Safety Management


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Highlight the importance of Roadside Safety & the appropriate Safety Treatment

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Roadside Safety Management

  1. 1. Roadside Safety Management The Safe Roadside Concept Gallant Chan Transportation Engineer
  2. 2. Deaths + Hospitalisations resulting from road crashes in Auckland Region
  3. 3. International Comparison of Deaths per 100,000 Population (2007) *Auckland Regional Road Safety Plan 2009/12
  4. 4. Vehicle Crashes <ul><ul><ul><li>During 2008, an average of 1 person was killed on New Zealand roadways each day. </li></ul></ul></ul><ul><ul><ul><li>Although there was a general down trend on road deaths, there is still a lot more to do to meet our Regional Road Safety Target. </li></ul></ul></ul>
  5. 5. New Zealand Single Vehicle Run Off Road Fatalities *Ministry of Transport
  6. 6. What happens if vehicle run off road and hit a roadside hazard? *
  7. 7. What happens if vehicle run off road and hit a roadside hazard? * Johnson City, Tennessee.
  8. 8. What happens if vehicle run off road and hit a roadside hazard? *
  9. 9. What happens if vehicle run off road and hit a roadside hazard? <ul><li>Some older and superseded terminal can be a dangerous hazard as well. </li></ul>
  10. 10. Most Frequently Objects Struck in 2006 *New Zealand Transport Agency
  11. 11. What’s the GOAL? <ul><ul><ul><li>Ideally keep vehicles on the road; or </li></ul></ul></ul><ul><ul><ul><li>At worst reduce crash severity if they do come off the road. </li></ul></ul></ul>
  12. 12. Roadside Safety Priorities <ul><ul><ul><li>Remove </li></ul></ul></ul><ul><ul><ul><li>Relocate </li></ul></ul></ul><ul><ul><ul><li>Redesign (reduce impact severity) </li></ul></ul></ul><ul><ul><ul><li>Redirect (shield) </li></ul></ul></ul><ul><ul><ul><li>Retro-reflect (delineate) </li></ul></ul></ul>
  13. 13. Roadside Safety Priorities - Remove * New Zealand Transport Agency Before
  14. 14. Roadside Safety Priorities - Remove After * New Zealand Transport Agency
  15. 15. Roadside Safety Priorities - Relocate Potentially to relocate underground * New Zealand Transport Agency
  16. 16. Roadside Safety Priorities - Redesign * New Zealand Transport Agency Redesigned so the culvert does not trap vehicle tire
  17. 17. Roadside Safety Priorities - Redirect * New Zealand Transport Agency Redirect vehicle from hitting a hazard
  18. 18. Roadside Safety Priorities - Retroreflect * Introduce retro reflectivity to enhance the awareness of objects/messages to drivers
  19. 19. Clear Zone Concept <ul><li>Clear Zone </li></ul><ul><li>The clear zone is the room available for vehicles that run off the road to regain control with minimum damage to both vehicles and occupants. </li></ul><ul><li>Measured from the edge line adjacent traffic lane including shoulder and other widths to the hazards. </li></ul><ul><li>Provide as much unobstructed roadside area as possible. </li></ul>
  20. 20. Standards for Roadside Safety * New Zealand Transport Agency Poor Roadside
  21. 21. Evolution of Clear Zone Concept <ul><li>9m clear zone introduced during 1967 </li></ul><ul><li>Variable clear zone introduced during 1977 </li></ul>
  22. 22. Variable Clear Zone <ul><li>Traffic Volumes </li></ul><ul><li>Design Speed </li></ul><ul><li>Cut and Fill Slopes </li></ul><ul><li>Horizontal Curve </li></ul>
  23. 23. Type of Barriers and Terminals <ul><li>Type of Barriers </li></ul><ul><li>Flexible – Wire Rope </li></ul><ul><li>Semi rigid – W-beam, & Thrie-beam </li></ul><ul><li>Rigid – New Jersey, & F shape concrete </li></ul><ul><li>Type of Terminals </li></ul><ul><li>Non-redirective – absorb energy </li></ul><ul><li>Redirective gating – controlled penetration </li></ul><ul><li>Redirective non-gating – roll up & smoothly redirective </li></ul>
  24. 24. Flexible Barriers <ul><li>Wire Rope (TL-3) </li></ul><ul><li>Most forgiving on vehicle occupants </li></ul><ul><li>Least Visually Intrusive </li></ul><ul><li>Greatest Deflection (1.25m – 2.7m) </li></ul>Armorwire Safence * CSP Pacific Roadside Systems
  25. 25. Flexible Barriers * CSP Pacific Roadside Systems
  26. 26. Semi-Rigid Barriers <ul><li>W-Beam, Thrie-Beam, & Nu-Guard (TL-3/TL-4) </li></ul><ul><li>Moderately forgiving on vehicle occupants </li></ul><ul><li>Moderate Deflection (approx. 1.0m) </li></ul>W-Beam Thrie-Beam * CSP Pacific Roadside Systems Nu-Guard
  27. 27. Semi-Rigid Barriers * CSP Pacific Roadside Systems W-Beam Nu-Guard
  28. 28. Rigid Barriers <ul><li>Concrete (TL-3 to TL-6) </li></ul><ul><li>Most commonly used in Medians and on Bridges </li></ul><ul><li>Least Forgiving </li></ul><ul><li>No Deflection </li></ul>F-Shape F-Shape *; CSP Pacific Roadside Systems New Jersey
  29. 29. Rigid Barriers New Jersey Concrete Barrier
  30. 30. End Terminals Tangential Terminal Flared Terminal
  31. 31. End Terminals ET-2000 (Tangential energy absorbing gating terminal) Fleat 350 (Flared energy absorbing terminal) * CSP Pacific Roadside Systems; Road Systems Inc. X-350 (Fully re-directive terminal; Flared or tangential) SKT (Tangential energy absorbing terminal)
  32. 32. End Terminals X-350 End Terminal * CSP Pacific Roadside Systems
  33. 33. Crash Cushions Universal TAU II (Fully re-directive crash cushion) * CSP Pacific Roadside Systems; Road Systems Inc. TRACC (Attenuating Crash Cushion) Quadguard
  34. 34. Crash Cushions Universal TAU-II Head On * CSP Pacific Roadside Systems Universal TAU-II Side Impact
  35. 35. Transitions <ul><li>Provided between barriers of different stiffness to prevent pocketing </li></ul>
  36. 36. Transitions * New Zealand Transport Agency
  37. 37. Some things to consider for Barrier Installation <ul><li>THIS LIST DOES NOT COVER ALL ISSUES TO BE CONSIDERED. COME TO SEE THE TRAFFIC SERVICES TEAM IF YOU ARE THINKING TO INSTALL SOME BARRIERS. </li></ul><ul><li>Location of Hazards </li></ul><ul><li>Is the hazard within Clear Zone? </li></ul><ul><li>Note: Barriers are hazard as well, however well designed complying barriers can reduce crash severity. </li></ul><ul><li>Lateral Offset / Shy line Offset </li></ul><ul><li>Desirable to place all roadside features beyond the shy line offset </li></ul><ul><li>Offsets ≥100km/hr: </li></ul><ul><ul><li>LHS = provide 3.0m </li></ul></ul><ul><ul><li>RHS = 2.0m </li></ul></ul>
  38. 38. Things to consider for Barrier Installation <ul><li>Terrain </li></ul><ul><li>Investigate likelihood vehicle would be on the ground, falling, or launching when hitting roadside features. </li></ul><ul><li>Ditch and Back Slopes (Clear Zone requirement). </li></ul><ul><li>Length of Need </li></ul><ul><li>Start beyond the tangential runout path to prevent errant vehicles from travelling behind the barrier and hit the hazard. </li></ul><ul><li>Flare barrier to reduce length of need. </li></ul>
  39. 39. Things to consider for Barrier Installation <ul><li>Accesses and Intersections </li></ul><ul><li>Check the sight visibility of drivers turning out of accesses. </li></ul><ul><li>Type of Barriers and Terminals </li></ul><ul><li>Assess the Test Level (TL) requirement. </li></ul><ul><li>Minimum TL on State Highway is NCHRP 350 TL-3. </li></ul><ul><li>Barrier Deflection </li></ul><ul><li>Assess Barrier Deflection to hazards. </li></ul><ul><li>Maintenance Access </li></ul><ul><li>Allow maintenance access. </li></ul>
  40. 40. Length of Need Barrier Installation Example
  41. 41. Standards for Roadside Safety * New Zealand Transport Agency <ul><li>Standards </li></ul><ul><li>NZTA State Highway Geometric Design Manual </li></ul><ul><li>NZTA Bridge Manual </li></ul><ul><li>NHI Highway Safety Features Workshop Course Notes </li></ul><ul><li>NCHRP Reports 350 </li></ul><ul><li>AS/NZS 3845:1999 </li></ul><ul><li>TNZ M23 </li></ul>
  42. 42. Introduction to Roadside Safety The End