Traffic safety on bus corridors - Nicolae Duduta - 27-Oct-2013

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Safety impact from bus rapid transit, factors impacting safety performance on a bus corridor, impact of safety countermeasures on operational performance. Case studies from Delhi, Bogota TransMilenio, Rio de Janeiro TransOeste.

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Traffic safety on bus corridors - Nicolae Duduta - 27-Oct-2013

  1. 1. Traffic Safety on Bus Corridors Nicolae Duduta EMBARQ, World Resources Institute ALC BRT Center of Excellence Webinar September 27, 2013 11am EST Please mute your microphones
  2. 2. What is the overall safety impact from implementing a BRT, Busway, or other type of bus system? What are the factors that impact safety performance on a bus corridor? How do safety countermeasures impact operational performance? Case studies Summary
  3. 3. Depends on the configuration of the new bus system, but also on what was there before Here: Calz. Independencia (Guadalajara) before BRT Overall safety impact
  4. 4. Overall safety impact Reduction in the number of lanes Shorter pedestrian crossings Central median Existing buses and minibuses replaced with a single operating agency
  5. 5. Overall safety impact
  6. 6. Overall safety impact
  7. 7. What is the overall safety impact from implementing a BRT, Busway, or other type of bus system? What are the factors that impact safety performance on a bus corridor? How do safety countermeasures impact operational performance? Summary
  8. 8. Crash frequency models Statistical models that aim to explain differences in crash rates at different locations through variables including traffic volumes, street geometry, land uses, etc. The preferred probability distributions for modeling crash data are Poisson and, more commonly, negative binomial The same street characteristic (e.g. block sizes) will have different impacts on crashes at different levels of severity It is recommended to develop crash frequency models for different types of crashes (e.g. vehicle collisions, pedestrian crashes, severe crashes, property damage crashes, etc.)
  9. 9. Crash frequency model results Guadalajara
  10. 10. Crash frequency model results Mexico City Safety impact analysis showed statistically significant safety improvements post BRT implementation
  11. 11. Crash frequency model results Removal of one lane per approach: -28% crashes Crosswalk shortened by 10m: -26% pedestrian crashes Central median: -28% vehicle collisions Left turn prohibitions: -20% all crash types
  12. 12. The safest place to be on a bus corridor is inside the bus The most dangerous place: walking to and from the station Fatalities on bus corridors Fatalities by Road User Type 0% Pedestrians 54% Car occupants 23% Motorcyclists 10% Bicyclists 5% Other 8%
  13. 13. Delhi Busway Traffic speeds and block sizes For each additional 10 m (30’) between signalized intersections: • 2% decrease in all crashes • 3% increase in severe crashes
  14. 14. TransMilenio, Av. Caracas, Bogota Traffic speeds and block sizes
  15. 15. TransOeste BRT, Rio de Janeiro Traffic speeds and block sizes
  16. 16. Av. das America, Rio de Janeiro Speed management Av. Caracas, Bogota
  17. 17. Metrobus Line 2, Mexico City Pedestrians do not use bridges and prefer to cross under them Crash frequency model: bridges have no statistically significant impact on pedestrian safety on urban arterials Pedestrian bridges
  18. 18. Metrobus BRT, Istanbul Pedestrian bridges are a good solution on expressways Crash frequency model: bridges are strongly correlated with lower pedestrian crash frequencies on expressways Pedestrian bridges
  19. 19. Curbside bus lane, Eje 2 Oriente, Mexico City Mid-block signalized crosswalks
  20. 20. What is the overall safety impact from implementing a BRT, Busway, or other type of bus system? What are the factors that impact safety performance on a bus corridor? How do safety countermeasures impact operational performance? Summary
  21. 21. Case study: TransOeste BRT, Rio de Janeiro Road safety inspection – proposed safety countermeasures targeted at speed reductions and improved pedestrian safety Microsimulation model – test the impact of countermeasures on operational performance
  22. 22. Safety recommendations Reducing speed from 70kmh to 60kmh (30 kmh at stations) Adding mid-block signalized crossings Reducing pedestrian signal delay
  23. 23. Pedestrian delay issues - TransOeste Mid-block signalized crosswalk, Av. das Americas
  24. 24. Pedestrian delay issues - TransOeste Mid-block signalized crosswalk, Av. das Americas
  25. 25. Pedestrian delay issues - TransOeste HCM recommends keeping pedestrian delay under 30 seconds (ideally under 10)
  26. 26. Impact on operations * Speed variability is defined here as the ratio of the standard deviation to the mean commercial speed, for all vehicles generated in the simulation. A lower speed variability coefficient indicates more reliable service. Slight negative impact on commercial speed (though still above 25kmh benchmark) Slight increase in travel times (+6 min terminal to terminal) Lower speed variability (i.e. more reliable service) Potential for significant safety benefits
  27. 27. Nicolae Duduta, nduduta@wri.org EMBARQ.org Further reading on this topic: EMBARQ’s safe design guidelines for BRT: http://www.embarq.org/en/traffic-safety-bus-corridors-pilot-version-road- test A TRR paper including the crash frequency models: http://www.brt.cl/understanding-road-safety-impact-of-high-performance- bus-rapid-transit-and-busway-design-features-2/ Next steps

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