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BRT Workshop - Bus Rapid Transit and Traffic Safety
 

BRT Workshop - Bus Rapid Transit and Traffic Safety

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O Centro de Excelência em BRT Across Latitudes and Cultures (ALC-BRT CoE) promoveu o Bus Rapid Transit (BRT) Workshop: Experiences and Challenges (Workshop BRT: Experiências e Desafios) dia ...

O Centro de Excelência em BRT Across Latitudes and Cultures (ALC-BRT CoE) promoveu o Bus Rapid Transit (BRT) Workshop: Experiences and Challenges (Workshop BRT: Experiências e Desafios) dia 12/07/2013, no Rio de Janeiro. O curso foi organizado pela EMBARQ Brasil, com patrocínio da Fetranspor e da VREF (Volvo Research and Education Foundations).

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    BRT Workshop - Bus Rapid Transit and Traffic Safety BRT Workshop - Bus Rapid Transit and Traffic Safety Presentation Transcript

    • Bus Rapid Transit and Traffic Safety Luis Antonio Lindau, Director, EMBARQ Brasil Nicolae Duduta, Associate Transport Planner, EMBARQ July 12, 2013
    • The impact of BRT systems on traffic safety Factors that influence safety on BRT corridors Relationship between safety and operational performance Summary
    • Mexico CityGuadalajara Bogota Curitiba Porto Alegre Istanbul Delhi Ahmedabad Vancouver Brisbane Rio, SP, BH PereiraCali In Brazil it comprised: road safety audits and inspections in 5 cities 190 km of corridors more than 2 million pax per day A global study
    • The impact of BRT systems on traffic safety Factors that influence safety on BRT corridors Relationship between safety and operational performance Summary
    • Overall safety impact of a BRT Case study: Macrobús, Guadalajara Calz. Independencia, 2007 (before BRT implementation)
    • Overall safety impact of a BRT Case study: Macrobús, Guadalajara Reduction in the number of lanes Shorter pedestrian crossings Central median Existing buses and minibuses replaced with a single operating agency
    • Monthly crashes before and after the implementation of the BRT 0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 0 50 100 150 200 250 Jan-07 Mar-07 May-07 Jul-07 Sep-07 Nov-07 Jan-08 Mar-08 May-08 Jul-08 Sep-08 Nov-08 Jan-09 Mar-09 May-09 Jul-09 Sep-09 Nov-09 Jan-10 Mar-10 May-10 Jul-10 Sep-10 Nov-10 Jan-11 Mar-11 May-11 Monthlycitywidecrashes(excludingtheBRTcorridor) MonthlycrashesontheBRTcorridor Citywide Crashes on the BRT Before During BRT construction During BRT
    • Impact on crashes by severity, per year Impact on traffic fatalities Annual fatalities in absence of BRT Annual fatalities with BRT Change in fatalities Baseline data Modeled baseline data Project data Modeled project data Macrobus BRT 1 3.5 0.3 1 - 2.5 Impact on traffic injuries Annual traffic injuries in absence of BRT Annual injuries with BRT Change in injuriesBaseline data Project data Macrobus BRT 96.8 30 - 66.8 Impact on all crashes Annual crashes in absence of BRT Annual crashes with BRT Change in crashesBaseline data Project data Macrobus BRT 2,341 1,010 - 1,331
    • 5000 3194 1 BRT lane 2 general traffic lanes Passenger per hour per direction (peak) 6 726 1 BRT lane 2 general traffic lanes Crashes per year Comparison between the bus lanes and the mixed traffic lanes
    • Overall safety impact of a BRT Case study: TransOeste, Rio de Janeiro Av. das Americas 2010 Av. das Americas 2012
    • Overall safety impact of a BRT Case study: TransOeste, Rio de Janeiro The layout of the BRT is very similar to Macrobus – center lanes, median stations, overtaking lanes But the street is considerably wider (up to 100 m) and speed limits are as high as 80kmh
    • Impact on safety? There is not yet enough data available to evaluate TransOeste However, the data so far show between 1.5 and 4.5 fatalities per month on Av. das Americas in 2012, some of them involving BRT vehicles, which could mean an increase in fatalities after BRT implementation
    • BRTs have the potential to significantly improve safety on the streets where they are implemented BRT systems where reductions in injuries and fatalities have been observed include Macrobus (Guadalajara), Metrobus (Mexico City), TransMilenio (Bogota), Janmarg (Ahmedabad) Reductions range from 30% (Metrobus) to 70% (Macrobus) But some systems have seen increases in fatalities (Delhi) or have a concerning number of fatalities (TransOeste) Overview of safety impacts
    • The impact of BRT systems on traffic safety Factors that influence safety on BRT corridors Relationship between safety and operational performance Summary
    • Methodology Crash frequency models Road safety inspections Discussions with BRT agency safety and operations staff Factors that influence safety on BRT corridors
    • Statistical models that aim to explain the differences in crash frequencies (or crash rates) at different locations (e.g. intersections) using variables related to geometry, traffic volumes, land use, etc. Commonly use a Poisson or negative binomial (Poisson- Gamma) distribution Crash frequency models
    • Crash frequency models Variables (Xi) Coefficients (α, βi) P Annual average daily traffic (AADT, thousands of vehicles) 0.016 0.074 Total length of all approaches to the intersection (L, meters) 0.003 0.010 Average number of lanes per approach 0.334 0.000 Cross street is through street (=1 if yes, =0 otherwise) 1.142 0.029 Major T junction (=1 if yes, =0 otherwise) 0.719 0.019 Constant -3.914 0.000 N = 133, LR χ2 (prob.) = 64.62 (0.000), Log likelihood = -141.580 Variables (Xi) Coefficients (α, βi) P Presence of a center median (=1 if yes, =0 otherwise) -0.349 0.004 Total number of approaches to the intersection (m) 0.424 0.000 Average length of approaches to the intersection (Lavg, meters) -0.008 0.036 Average number of lanes per approach 0.492 0.000 Cross street is through street (=1 if yes, =0 otherwise) 0.820 0.000 Major T junction (=1 if yes, =0 otherwise) 0.748 0.008 Constant -1.197 0.002 N = 132, LR χ 2 (prob.) = 135.76 (0.000), Log likelihood = -141.580, chibar2 (prob.) = 341.99 (0.000) Table 1: Severe crash frequency model for Guadalajara (Poisson) Table 2: All crash frequency model for Guadalajara (negative binomial)
    • Factors influencing crash frequencies Counterflow Counterflow lanes were strongly correlated with higher crash frequencies across all our models
    • Factors influencing crash frequencies Street width and intersection size and complexity Metrobus Line 1, Mexico City Road width and complexity of intersections were the most important predictors of crash frequencies.
    • Factors influencing crash frequencies Location of bus lanes Central median Shorter pedestrian crossings Fewer mixed traffic lanes Some 4-way intersections turned into T junctions
    • The safety impact of large blocks For each additional 10 m (30’) between signalized intersections: • 2% decrease in all crashes • 3% increase in severe crashes
    • Wider streets are more problematic for safety Wide, complex intersections can easily become “black spots” The length of crosswalks is key for pedestrian safety (for each additional meter a pedestrian needs to cross without a median, there is a 2 to 3% increase in pedestrian crashes) Counterflow is the most dangerous bus lane configuration Overview of findings from data analysis
    • A detailed inspection of a street with the objective of identifying safety issues Involves walking along the entire length of a study site (in our case, a BRT corridor) documenting problems related to infrastructure and road user behavior Road safety inspections
    • Fatalities on BRT corridors by road user type Fatalities by Road User Type 0% Pedestrians 54%Car occupants 23% Motorcyclists 10% Bicyclists 5% Other 8% The safest place to be on a bus corridor is inside the bus The most dangerous: pedestrian crossing the avenue
    • Crossing in mid-block
    • Mid-block signalized crosswalk - TransOeste
    • Pedestrian signal timing
    • Pedestrian signal timing
    • Pedestrian signal timing
    • Pedestrian signal timing
    • Pedestrian signal timing
    • Pedestrian signal timing
    • Pedestrian signal timing
    • Pedestrian signal timing
    • Pedestrian signal timing
    • Pedestrian signal timing
    • Pedestrian signal timing
    • Pedestrian signal timing
    • Pedestrian signal timing
    • Pedestrian signal timing
    • BRT Safety recommendations 41 41 SPEED REDUCTIONS: PEDESTRIAN CROSSINGS: INCREASED SIGNAL TIME: To increase safety on Av. das Americas, EMBARQ proposed…
    • Speed at Avenida das Américas 42
    • Speed • It is very difficult to control speed through signage and enforcement • Streets should be designed for their desired speed
    • Pedestrian bridges Pedestrian bridges rarely work, as pedestrians prefer to cross under them In some cases, this is due to the fear of crime (e.g. research in Cape Town showing pedestrians are concerned of being assaulted or robbed on overpasses) Our research shows they are not effective for safety on typical urban arterials - no significant impact on pedestrian crash frequencies The exception is on high-speed, high-volume roads (e.g. Autopista Norte, Bogota, where locations with pedestrian bridges had four times fewer pedestrian crashes
    • Improving the BRT routes Based on EMBARQ’s recommendations… • Stations barriers were improved to avoid unregulated and unsafe pedestrian crossings • Install lateral barriers in the platform doors • The city is studying to reduce speed limits from 80km/h to 60 km/h in Avenida das Américas
    • 2011: Signalized mid-block crossing on Eje 2 Oriente, with no traffic calming. Vehicles did not stop for pedestrians. 2012: Speed hump installed before the pedestrian crossing, slowing traffic down and allowing pedestrian to cross safely. More closely spaced signalized intersections can help avoid unsafe speeds But drivers may disregard signals where the only conflict is with pedestrians Speed reductions
    • There is often a considerable difference between how streets are meant to be used and how people actually use them: Jaywalking, including crossing under pedestrian bridges, jumping over guardrails, destroying guardrails Crossing on red (pedestrians) or driving on red (drivers) The key to designing safer streets is understanding road user behavior and how the design of the infrastructure can be better adapted to that Overview of findings from inspections
    • The impact of BRT systems on traffic safety Factors that influence safety on BRT corridors Relationship between safety and operational performance Summary
    • Most safety recommendations involved speed reductions, traffic calming, or additional traffic signals This raises the question of how safety countermeasures would impact the operational performance of a BRT We illustrate the relationship between safety and operational performance with a case study from TransOeste Safety, operations, and capacity
    • The relationship between safety and operational performance TransOeste BRT, Rio de Janeiro, Brazil Methodology Identified safety issues Proposed countermeasures Applied a microsimulation model to test the impact of safety countermeasures on: Operating speeds Travel times Speed variability
    • The relationship between safety and operational performance TransOeste BRT, Rio de Janeiro, Brazil Main safety issues: High speed road: 80 km/h speed limit Few crossing opportunities for pedestrians Jaywalking is a common problem
    • The relationship between safety and operational performance TransOeste BRT, Rio de Janeiro, Brazil Main safety recommendations: Lowering the speed limit to 60 km/h Adding mid-block signalized crossings Improving signal timing to reduce pedestrian delay
    • The relationship between safety and operational performance TransOeste BRT, Rio de Janeiro, Brazil Indicator Service Baseline 60 km/h 60/30 km/h Complete Speed (km/h) Express 32 31.5 29.6 29.6 Local 25.6 25.6 25.4 25.4 Travel time (min) Express 71 72 77 77 Local 89 89 89 89 Speed variability* Express 0.19 0.18 0.16 0.16 Local 0.16 0.15 0.15 0.16 * 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. Key finding: Slight negative impact on operating speed and travel time
    • The relationship between safety and operational performance TransOeste BRT, Rio de Janeiro, Brazil * 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. Key findings: Potential for significant safety benefits No impact on passenger capacity Magnitude of operational impacts negligible compared to safety benefits Performance indicator Baseline Project Change Source All crashes n/a n/a -15% to -67% Elvik and Vaa 2004 Operating speed 32 km/h 29.6 km/h -2.4 km/h Microsimulation Travel time 71 min 77 min + 6 min Microsimulation Speed variability 0.19 0.16 - 0.03 Microsimulation Capacity (pphpd) 18,800 18,800 No impact Based on Hidalgo et al. (2011)
    • More resources on this topic WCTR Presentation: C4-6 Public Transport Safety (Slot 6g/Room g/13:40-15:20 Tue.) More detailed presentation on the link between safety and operational performance using the TransOeste case study Publications available online: Understanding the Road Safety Impact of High Performance BRT and Busway Design Features Technical paper including the methodology and main findings from the crash frequency models shown here Available online at: http://www.brt.cl/understanding-road-safety-impact-of- high-performance-bus-rapid-transit-and-busway-design-features-2/ Traffic Safety on Bus Corridors Safe design concepts for BRT and Busways Available online at: http://www.embarq.org/en/traffic-safety-bus-corridors- pilot-version-road-test (English, Spanish, Portuguese)
    • Thank you Luis Antonio Lindau, tlindau@embarqbrasil.org Nicolae Duduta, nduduta@wri.org