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Open Access Publications from the University of California

The Safe Transportation Research and Education Center (SafeTREC) mission is the reduction of transportation-related injuries and fatalities through research, education, outreach, and community service. 

 

Founded in 2000 as the Traffic Safety Center (TSC), the Center was renamed in 2009 to more accurately reflect the mission to encompass safety and travel risk in a multimodal transportation system; a robust and diverse research agenda across multiple disciplines; and development and enhancement of curriculum, training, and outreach on the graduate and undergraduate levels, as well as for professionals and members of the community.

 

SafeTREC is part of the University of California, Berkeley, and is affiliated with the School of Public Health and the Institute of Transportation Studies, with additional partnerships with the Department of City and Regional Planning, Public Policy, and Transportation Engineering. Our research is carried out by faculty at UC Berkeley with assistance from post-doctoral scholars, research staff, and graduate student researchers. We also help the California Office of Traffic Safety administer its Community Pedestrian and Bicycle Safety Training workshops and support various safety initiatives from other California agencies, Including the California Department of Transportation (Caltrans). 

 

SafeTREC's three emphasis areas are:


Data Analysis and Data Tools is a necessity for understanding safety/mobility in transportation / land use planning in California.  SafeTREC will build on current large scale data efforts (geocoding 15 years of traffic crashes in California, adding pedestrian and bicycle infrastructure elements to the State Highway data base, building a statewide Tribal Road Safety Data Base) to construct state-of-the-art data analysis and mapping tools for use by government agencies, researchers, and the general public.


Technology for Road Safety, including crash warning and avoidance systems, smart infrastructure sensing systems, and automated vehicles. SafeTREC will be in the forefront of evaluating the benefits and costs of these rapidly emerging technologies. This emphasis area will also utilize technology for in-depth analysis of crash reports, data visualization techniques, and developing novel transportation safety management methods.


Policy Analysis and Community Outreach will continue to be a necessity to connect with California’s extremely diverse communities to improve road safety and encourage active transportation. SafeTREC will build on existing policy analyses (e.g., Safe Routes to School) and community outreach (e.g., Community Pedestrian and Bicycle Safety Training, data analyses and presentations for local governmental agencies) to create a national model for policy analysis and community outreach.

Cover page of Assessing and Addressing the Mobility Needs of an Aging Population

Assessing and Addressing the Mobility Needs of an Aging Population

(2019)

The mobility needs of an aging population is one of the most substantial challenges facing California in the coming decades. The number of residents age 65 and older is expected to double between 2012 and 2050, and the number age 85 and above is expected to increase by over 70% between 2010 and 2030. Declines in physical function related to age may reduce mobility options dramatically. A survey of 510 residents age 55 and older in Contra Costa County was conducted to determine mobility patterns and limitations related to age and other factors. Results of the survey indicate that a majority of seniors are car dependent. However, some older adults miss important activities due to mobility limitations associated with increasing age, poorer health, living alone, not having a licensed driver in the household, and having a disability. Mobility options are also limited in some geographic areas and demographic groups. Importantly, older adults want to “age in place.” Based on these findings and those in related studies, the travel options and the quality of life for older adults, now and in the future, can be greatly enhanced if efforts are made to develop mobility solutions beyond use of private vehicles. The findings support the recommendations of recent regional plans such as the Coordinated Public Transit–Human Services Transportation Plan (2018), adopted by the Metropolitan Transportation Commission (MTC) of the San Francisco Bay Area, which recommends supporting a range of mobility options centered around shared mobility and accessibility for populations at risk for limited mobility.

Cover page of Prehospital Response Time and Traumatic Injury—A Review

Prehospital Response Time and Traumatic Injury—A Review

(2018)

A significant proportion of fatalities from motor vehicle collisions (MVC) could be prevented through better emergency medical service (EMS) care. Despite a lack of conclusive research, there is a consensus that prehospital time (the time between the MVC and the patient’s arrival at the hospital) must be reduced as much as possible. Many studies use response time (the time between EMS dispatch and arrival at the scene) as an indicator of overall prehospital time and a metric of EMS performance. However, there are other components of prehospital time that may be equally important, including the discovery time between the collision and EMS notification, the on-scene time, and the transport time from the scene to the hospital. In rural MVCs, the discovery time can be substantial if there are no witnesses or survivors capable of calling emergency services. Technologies that automatically detect MVCs can shorten discovery times in such circumstances. Transport times depend on the distance between the crash scene and the hospital; this time could be reduced by increasing access to trauma centers, especially in rural areas. On scene time is a component of the total time, however there is a trade-off between minimizing scene time to reduce total time and providing optimal on-scene care. Increasing capacity of EMS personnel and/or utilizing technology such as telemedicine should be considered as part of this trade-off. Future research is needed to determine the relative benefits and costs of reducing any of these segments of prehospital time.

Cover page of Evaluating Research on Data Linkage to Assess Underreporting of Pedestrian and Bicyclist Injury in Police Crash Data

Evaluating Research on Data Linkage to Assess Underreporting of Pedestrian and Bicyclist Injury in Police Crash Data

(2018)

Traffic safety decisions are based predominantly on information from police collision reports. However, a number of studies suggest that such reports tend to underrepresent bicycle and pedestrian collisions. Underreporting could lead to inaccurate evaluation of crash rates and may under- or overestimate the effects of road safety countermeasures. This review examined ten studies that used data linkage to explore potential underreporting of pedestrian and/or bicyclist injury in police collision reports. Due to variations in definitions of reporting level, periods of study, and study locations, it was difficult to directly compare the studies. Even among the six studies using the hospital link definition, estimates of reporting levels ranged from 44 to 75 percent for pedestrian crashes, and from 7 to 46 percent for bicycle crashes, suggesting a severe underreporting problem. However, few of the studies provided estimates of the error around their reporting level estimates, and as a result, it is difficult to determine the true level of underreporting. It may be that bicycle and pedestrian crashes appear in both police and hospital datasets but are less likely to be linked. Due to linkage error, link rate can only be used to estimate reporting level. Without the variance of that estimate, the effect of underreporting on traffic safety analyses cannot be accurately determined. Future studies should include estimates of the error present in their data linkage process for greater accuracy of the underreporting in police data. Datasets should be designed for easier linkage with hospital data and other datasets.

Evaluation of Injury Severity Updates in California Collision Data

(2018)

Fatal or injury collisions in California must be reported to the California Highway Patrol (CHP) for inclusion in the Statewide Integrated Traffic Records System (SWITRS). After records have been entered into SWITRS they are made publicly available and are accessible through the CHP’s report and data retrieval site called I-SWITRS. However, records accessed in SWITRS are considered provisional and can be updated several years after initial entry. This includes the injury severity level of collisions. If the collision data was accessed prior to an injury severity update, the agency retrieving the data may unknowingly be working with an outdated version. This can have an impact on government agencies use of data driven safety analyses to apply for safety improvement funding in order to achieve key safety goals in reducing fatal and serious injury collisions. This paper evaluated the frequency and level of injury severity changes for severe injury and fatal collisions that occurred in 2016 and which were retrieved at four different times between March 2017 and June 2018. In total, 94 injury collisions were upgraded to fatal collisions (2.653%) and 2 fatal collisions were downgraded to severe injury collisions (0.056%) out of the 3,543 total fatal collisions that occurred in 2016. The authors concluded that government agencies need to perform regular checks of their data to ensure that fatal and severe injury collisions are properly accounted for to maximize their ability to achieve safety performance targets.

Cover page of Evaluation of Injury Severity Updates in California Collision Data

Evaluation of Injury Severity Updates in California Collision Data

(2018)

Fatal or injury collisions in California must be reported to the California Highway Patrol (CHP) for inclusion in the Statewide Integrated Traffic Records System (SWITRS). After records have been entered into SWITRS they are made publicly available and are accessible through the CHP’s report and data retrieval site called I-SWITRS. However, records accessed in SWITRS are considered provisional and can be updated several years after initial entry. This includes the injury severity level of collisions. If the collision data was accessed prior to an injury severity update, the agency retrieving the data may unknowingly be working with an outdated version. This can have an impact on government agencies use of data driven safety analyses to apply for safety improvement funding in order to achieve key safety goals in reducing fatal and serious injury collisions. This paper evaluated the frequency and level of injury severity changes for severe injury and fatal collisions that occurred in 2016 and which were retrieved at four different times between March 2017 and June 2018. In total, 94 injury collisions were upgraded to fatal collisions (2.653%) and 2 fatal collisions were downgraded to severe injury collisions (0.056%) out of the 3,543 total fatal collisions that occurred in 2016. The authors concluded that government agencies need to perform regular checks of their data to ensure that fatal and severe injury collisions are properly accounted for to maximize their ability to achieve safety performance targets.

Cover page of Traffic Safety Among Latino Populations in California: Current Status and Policy Recommendations

Traffic Safety Among Latino Populations in California: Current Status and Policy Recommendations

(2015)

This report summarizes the information gained from two community forums held in Latino communties in California, provides an analysis of trends in injury and demographic data, and reviews best practices for increasing safety and preventing injury in Latino populations. It highlights pressing traffic safety needs and presents recommendations. It is our goal that this report will serve as a prototype for policy, enforcement and program development to address traffic safety issues for Latinos in California.

Cover page of Complete Streets: From Policy to Practice in the San Francisco Bay Area

Complete Streets: From Policy to Practice in the San Francisco Bay Area

(2014)

This paper describes how regional funding guidelines can affect local adoption of Complete Streets projects. The Metropolitan Transportation Commission (MTC), the regional Metropolitan Planning Organization for the nine-county Bay Area region in California, has developed a funding approach called the One Bay Area Grant (OBAG) for the allocation of funds for the 2012-2016 Congestion Mitigation and Air Quality (CMAQ) and Surface Transportation Program (STP) across the Bay Area. Each jurisdiction receiving funding through OBAG was required to demonstrate compliance with Complete Streets (CS) policies either by passing a resolution or by certifying that its general plan circulation element was compliant with California’s Complete Streets Act of 2008. This analysis examines the extent and manifestation of this compliance. The OBAG framework allocated significantly more funding to County Congestion Management agencies than was provided during the prior CMAQ/STP cycle (Cycle 1 CMAQ). It also gave counties increased flexibility in decision making by removing program specific silos that were present in Cycle 1 CMAQ. This increased flexibility resulted in an increase in the number of multi-modal projects funded through OBAG. OBAG’s regional funding requirements for Complete Streets compliance through policy have the potential to influence Complete Streets implementation by local agencies in the long term and to serve as a model for other state or local planning agencies seeking to increase investments in pedestrian and bicycle infrastructure.