Traffic Safety on Bus Corridors: Pilot Version - Road Test
This guidebook provides bus agencies, local jurisdictions, as well as regional and international organizations with a set of suggested design, planning, and operational criteria that should be considered in the planning and design of new bus systems. This is a preliminary version of the guidelines and should be regarded as a work in progress. It is being released by EMBARQ as a pilot version to be tested by our centers as well as external partners in 2012. The lessons learned from this road test will be incorporated into a final version to be released in 2014, and all the road testers will be acknowledged in the final publication.
Traffic safety is an aspect that has consistently been missing from publications and planning guides for bus rapid transit (BRT) and Busway corridors. This was an important gap. Traffic fatalities are projected to become the fifth leading cause of premature death worldwide by 2030, ahead of HIV/AIDS, violence, tuberculosis, or any type of cancer, and most of this growth is expected to occur in developing world cities, according to the World Health Organization.
The impact of bus systems on road safety is particularly important because they tend to be situated along major urban arterials. A study in New York City has found that arterials account for about 15% of the road network in the city, but over 65% of severe pedestrian crashes (Viola et al. 2010). A study in Mexico City indicates that all crash types are heavily concentrated on the main arterials, where major bus routes are usually located (Chias Becerril et al. 2008). The implementation of a high capacity transit system on any urban arterial will attract large volumes of pedestrians to streets where risks are already high. In New York, streets with bus routes had consistently shown higher pedestrian crash rates than any other streets (Viola et al. 2010). In Porto Alegre, Brazil the presence of Busway corridors and bus stations was correlated with higher mid-block pedestrian crash rates (Diogenes and Lindau 2009). On the other hand, the implementation of some BRT systems, such as Macrobus in Guadalajara and TransMilenio in Bogota, resulted in a significant reduction in crashes and fatalities on the respective corridors. There appears to be a wide range of potential safety impacts from the implementation of bus systems.
EMBARQ has been conducting research on the traffic safety aspects of bus system planning, design, and operations, collecting and analyzing data from over 30 bus corridors from developing world cities, conducting road safety inspections and audits on BRT and Busways, and interviewing road safety experts and bus agency staff to learn from their experience with crashes on bus corridors. We were thus able to identify the main risks and common crash types on bus corridors, and also the safety impact of different BRT and Busway design features. We found that some key design elements of bus systems can significantly improve safety (e.g. closed stations with high platforms, center-lane systems with left turn interdictions) while others can increase the risk of crashes (e.g. counterflow lanes). We also found that the overall geometry of the road and especially the size and complexity of intersections are important predictors of crash rates on bus corridors. Based on these findings, we were able to formulate a set of design recommendations for improving road safety on bus corridors.
This guidebook is designed as a practical guide for transportation planners, engineers, and urban designers involved in the planning and design of bus systems. It covers a broad spectrum of system and corridor types, ranging from curbside bus priority lanes all the way to high capacity, multilane BRTs.
While the main purpose of the guidelines is to illustrate how safety can be improved in bus system design, we also considered how each of our design concepts impact bus operations (in terms of passenger capacity of the bus system, fleet size requirements, and pedestrian capacity of areas around stations) as well as accessibility. The designs illustrated in this guidebook represent best practices that balance the safety of all road users with the need to provide high passenger capacity and also provide accessible, liveable urban spaces.
This is a preliminary version of the guidelines and should be regarded as a work in progress. It is being released by EMBARQ as a pilot version to be tested by our centers as well as external partners in 2012. The lessons learned from this road test will be incorporated into a final version to be released in 2014, and all the road testers will be acknowledged in the final publication.