Safety

The Marked Crosswalk Dilemma: Uncovering Some Missing Links in a 35-Year Debate

Mitman, Meghan Fehlig
Ragland, David R.
Zegeer, Charles V.
2008

Largely in response to several landmark safety studies, as an official or unofficial policy, many agencies across the U.S. have elected to remove marked crosswalks at uncontrolled intersections, or have shown resistance to installing them in the first place. This approach results in unacceptable pedestrian mobility restrictions, yet such restrictions are often not considered in policy-making. As such, there is a need for roadway system owners to develop strategic safety guidelines to address the marked crosswalk dilemma. Since 2005, the UC Berkeley Traffic Safety Center, in a study funded...

High Visibility Enforcement Programs: California’s State and University Traffic Safety Partnership

Cooper, Jill F.
Kan, Irene
Cadet, Akilah
Rauch, Sharleen
Murphy, Christopher J.
2009

Traffic collisions are a leading cause of death and injury in California and the number one cause of death for people between the ages of one and 44. High-visibility enforcement programs (HVEs) are administered nationwide by the National Highway Traffic Safety Administration, and combine intensive enforcement of a particular traffic safety law with widespread media and public education campaigns. HVE programs have been shown to be effective in reducing alcohol-impaired driving and promoting seat belt use. A major challenge in implementing HVEs, however, exists among local police agencies,...

A 3D Computer Simulation Test of the Leibowitz Hypothesis

Barton, Joseph E.
Cohn, Theodore E.
2007

Do large objects appear to approach more slowly than smaller objects traveling at the same speed? If so then this might help explain the inordinately high accident rates involving large vehicles such as buses and trains. To test this, this study constructed an experiment using a 3D visual simulator in which different sized textured spheres approached at different speeds. We found that observers consistently judged the smaller sphere to be the faster, even in cases where the larger sphere was traveling at up to twice the speed of the smaller. Analysis of these results suggests that the...

An Intensive Pedestrian Safety Engineering Study Using Computerized Crash Analysis

Ragland, David R
Markowitz, Frank
MacLeod, Kara E
2003

Over the past year, the San Francisco Department of Parking and Traffic (DPT) conducted an intensive pedestrian-safety engineering study, the PedSafe Study. PedSafe was funded by the Federal Highway Administration (FHWA)*, which also funded companion studies in Las Vegas and Miami. The study was designed to analyze pedestrian injuries by zones (i.e., neighborhoods or districts) and to identify those most amenable to prevention efforts. The DPT expects to utilize the methodology and information from the PedSafe study to help shape a citywide pedestrian master plan. This paper describes the...

Gap acceptance for vehicles turning left across on-coming traffic: Implications for Intersection Decision Support design

Ragland, David R
Arroyo, Sofia
Shladover, Steven E.
Misener, James A.
Chan, Ching-Yao
2006

A left-turning vehicle (Subject Vehicle, SV) attempting to cross the path of an oncoming vehicle (Principal Other Vehicle, POV) at an intersection typically does not have the right of way. The main task of the SV driver is to find an adequate opportunity in opposing traffic to initiate the left-turn maneuver. To reduce the probability of a conflict, warning systems, such as Intersection Decision Support (IDS) systems, are being developed. These systems alert drivers of SV vehicles attempting to negotiate a left turn about traffic approaching from the opposite direction. The current paper (...

The Effects of Transportation Corridor Features on Driver and Pedestrian Behavior and on Community Economic Vitality: Final Study Report

Sanders, Rebecca L. PhD
Griffin, Ashleigh MS, MCP
MacLeod, Kara E. MHP
Cooper, Jill F. MSW
Ragland, David R. PhD, MPH
2012

This report presents the results from a multiyear effort to develop and test performance measures for evaluating the impact of landscaping and roadside features on pedestrian and bicyclist safety and mobility and economic vitality for Caltrans’ urban arterial network. The first phase of the study was a literature review, and the second phase focused on developing performance measures. The third and fourth phases focused on testing the proposed performance measures consisting of an infrastructure analysis, policy review, safety analysis and a pedestrian and bicyclist intercept survey on two...

Error Consideration for Geocoding Police Reported Collision Data in California

Bigham, John
Oum, Sang Hyouk
2014

Geographic Information Systems (GIS) are frequently used to analyze collision data. In order to utilize GIS, the data must be geocoded, or assigned a latitude and longitude coordinate by translating a descriptive location onto street network data. However, the ability for accurate spatial analysis can be limited by geocoding errors that may occur due to limitations in data collection technologies, incorrect data entry due to human error, or inaccurate street reference data. In the state of California there is an increased opportunity for data entry errors, given the long sequence of events...

Driver/Pedestrian Understanding and Behavior at Marked and Unmarked Crosswalks

Mitman, Meghan F.
Ragland, David R
2008

Pedestrian injuries at crosswalk locations represent a significant problem. In 2002, 22.7 percent of US pedestrians involved in collisions were in a crosswalk at the time of the collision, and over 96% of these occurred at an intersection. Almost all crosswalk collisions resulted in pedestrian injury or fatality (98.6 percent), and about one-third resulted in severe or fatal injury (National Automotive Sampling System (NASS) and General Estimates System (GES) 2002).As the owner of the California State Highway System, Caltrans is responsible for providing access to safe and convenient...

Comparison of collisions on HOV facilities with limited and continuous access

Jang, Kitae
Chung, Koohong
Ragland, David R.
Chan, Ching-Yao
2008

This paper describes comparisons of traffic safety during the morning and afternoon peak hours in extended stretches of eight High Occupancy Vehicle (HOV) lanes with two different types of access – four corridors with continuous access and the others with limited access. Traffic collision patterns in two different types of HOV lanes were investigated by evaluating 1) the differences in collision distribution, severity, types of collisions and per lane traffic utilization, 2) spatial distribution of collision concentrations by using Continuous Risk Profile (CRP) approach, and 3) collision...

Prehospital Care of Road Traffic Injuries in Chiang Mai, Thailand

Brown, MD, Ted
2003

Road traffic accidents (RTAs) cause enormous morbidity and mortality in developing countries. The Global Burden of Disease Study projected that RTAs will be the third highest cause of disability adjusted life years (DALYs) by 2020. Ninety percent of the DALYs due to RTAs are in developing countries. Because the majority of trauma deaths in developing nations occur in the prehospital setting, it is imperative that emergency medical systems be established and improved in such countries. Two studies in Central America found that increasing the number of emergency dispatch units and...