Traffic
Safety Center Builds on Its First Five Years
Bridging research and practice to advise agencies and train new professionals, it makes a major contribution to California's federal safety program participation.
When President Bush signed SAFETEA-LU, the new federal transportation funding bill, into law last year, it set in motion a top-to-bottom mechanism for states to prioritize road safety improvements. It places a number of new requirements on state transportation agencies in order for them to qualify for funds.
On September 26, 2006, less than a year after the federal bill was signed, the California Secretary of Business, Transportation and Housing approved a key document that will enable the state to take part in this new program. It is the California Strategic Highway Safety Plan, and the UC Berkeley Traffic Safety Center is a member of the advisory board that helped to develop it.
"This is a statewide, integrated, collaborative approach to improving safety on California's roadways," explained David Ragland, Director of the Traffic Safety Center and an active participant in advising the California Department of Transportation (Caltrans) on how to evaluate safety needs and devise policies and programs to address them in order to comply with the federal law. Traffic Safety Center projects have covered a broad spectrum of topics over the years, ranging from collisions involving alcohol, intersection collision prevention, pedestrian and bicycle safety, child passenger safety, and traffic safety in rural areas.
As required by SAFETEA-LU, states must first devise a plan. The second part of the two-step effort is the development of a State Highway Safety Improvement Program. Meeting the federal requirements will make the state eligible for its full share of funds. The plan must be completed by October 1, 2007 in order for the state to qualify.
A Holistic, Proactive Approach
Ragland said that this kind of collaborative, "big-picture" work was necessary to tackle safety issues successfully.
Crashes
result from three factors, singly or in different combinations: the vehicle,
the driver (human factors) and the road environment (which
can include weather as well as pavement, signs, lighting and the like). For
example, a collision may result from faulty brakes, an impaired driver, or
a curve that is too tight for the prevailing speed. As the diagram (based on
national data) shows, human
factors are involved in nearly all crashes, some 93 percent, but
a closer look shows the interlocking nature of the three elements involved
when a crash occurs. Road environment factors are an element more than one-third
of the time, and vehicle factors are important in just over one crash in 10.
When the other factors are filtered out, human factors are the sole reason
for 57 percent of traffic crashes, the road environment is responsible for
3 percent, and vehicle factors for 2 percent. These figures
support the importance of a holistic approach to roadway safety.
At approximately the same time that the initial Strategic Highway Safety Plan was approved, Caltrans delivered to the Federal Highway Administration (FHWA) The 2006 California Highway Safety Improvement Program 5 Percent Report, another key requirement under the federal law. The Traffic Safety Center made significant contributions to developing this document, too. As stipulated in the enabling legislation, the document, which every state must prepare, describes the 5 percent of public roadways in the state "exhibiting the most severe safety needs" in satisfaction of FHWA requirements under the new law.
In addition to Caltrans and the TSC, participants included:
- California Highway Patrol (CHP)
- California Department of Motor Vehicles (DMV)
- Federal Highway Administration (FHWA)
- Mothers Against Drunk Driving (MADD)
- California State Association of Counties (CSAC)
- County Engineers Association of California (CEAC)
- League of California Cities
- California Department of Health Services (DHS)
This latest round of activity is in keeping with one of the TSC's priorities, which is to bridge the gap between research and practice by participating in and advising task forces. It also provides technical advice to state and local agencies and non-governmental organizations, ranging in size and scope from Caltrans to the small East Bay city or Emeryville, or community groups, such as community activists in Oakland's Chinatown or the farmworker communities of the Central Valley.
"These recent contributions reflect the center's unique capacity to advance traffic safety theory and practice because of its core competencies," Ragland noted. They are threefold, he explained:
- Teaching: training students for future roles in promoting and spreading understanding of traffic safety,
- Applied research: applying findings from the center's academic research to real-world solutions to real-world problems, and
- Technical support for California transportation agencies and non-governmental groups, as well as service on task forces and advisory groups.
Traffic Safety Center faculty teach two graduate courses, one offered through the School of Public Health, and the other through Civil and Environmental Engineering, and jointly sponsored by both. They are: "Public Health Injury Prevention and Control," which explores statistical and policy analysis of public health and injury prevention, and "Traffic Safety and Injury Prevention," which integrates engineering, behavioral science, and vision science into a comprehensive approach to traffic safety.
In addition, the TSC hosts the Traffic Safety Seminar, which is open to the University community and the general public featuring both University and outside experts in traffic safety.
In the 2005-2006 academic year, the Traffic Safety Center hosted on separate occasions pedestrian safety expert Charles V. Zegeer, and two leaders in safety assessment methods for road designs, Jake Kononov and Bryan Allery.
Zegeer is Associate Director of the University of North Carolina’s Highway Safety Research Center and director of the Pedestrian and Bicycle Information Center. He has written numerous reports, including the Federal Highway Administration’s Pedestrian Facility User’s Guide and the 2004 edition of its Annual Review of Pedestrian Safety Research.
Zegeer's lecture was closely modeled on a September 2005 report he prepared for the Federal Highway Administration (FHWA), "Safety Effects of Marked Versus Unmarked Crosswalks at Uncontrolled Locations." This is a well-documented contribution to much-debated topic of the appropriate use of crosswalks, and how much safety they truly provide.
The study analyzed five years worth of data about pedestrian crashes at 1,000 marked crosswalks and 1,000 matched unmarked sites in comparable locations. All of them were "uncontrolled," meaning there was no signal or stop sign regulating traffic.
Key results from the study were as follows:
- on two-lane roads, marked crosswalks alone were no safer than unmarked crosswalks;
- on low-volume multi-lane roads, marked and unmarked crosswalks provided the same amount of protection;
- on multi-lane roads with high traffic volumes (upwards of 12,00 vehicles per day), a marked crosswalk by itself, without other safety enhancements, was associated with greater pedestrian danger;
- the presence of a raised median provided significantly greater protection on multi-lane roads compared to no median;
- as traffic volume rose, crash rates went up for marked and unmarked crosswalks, but they rose much more steeply for marked crosswalks when rates are above 10,000 vehicles a day.
Zegeer emphasized that the important finding was not that marked crosswalks should not be used, but that they should be used appropriately. (Read more in the TSC Newsletter.)
Kononov and Allery are engineers with the Colorado Department of Transportation (CDOT), who have written and spoken extensively on methods that they have devised and deployed to better measure roadway safety that are more transparent and easier to implement.
Roadway designs' effectiveness in moving traffic is traditionally measured by the Level of Service (LOS), which rates speed and ease of travel, volume of traffic that can be accommodated and other indicators of roads' convenience and efficiency for users. However, LOS is not connected to a roadway's safety.
The 1998 federal highway bill, the Transportation Equity Act for the 21st Century, TEA-21, required that safety be explicitly considered in the planning process (similar to the way that environmental impacts must be considered). However, much remains to be understood about the best way to measure safety and how to decide where money for safety improvements would be best spent.
In order to address this issue, the Colorado Department of Transportation has devised a system that expands the LOS ranking to include safety. They call it Level of Service of Safety (LOSS). (Read more in TSC Newsletter.)
Last updated: October 19, 2006