Evaluation

Methods for Identifying High Collision Concentration Locations for Potential Safety Improvements

Geyer, Judy
Lankina, Elena
Chan, Ching-Yao
Ragland, David R.
Pham, Trinh
Sharafsaleh, Mohammad A.
2008

The California Department of Transportation (Caltrans) uses Table C and related documents to identify and to investigate locations within the state highway system where a relatively large number of collisions occur. In earlier years, a task force evaluated the process of generating and using these reports and found that there was much room for improvements. A list of recommendations was made. The efforts undertaken within this project is part of the effort to make the process of safety investigations and improvements more efficient and productive. This report summarizes the work carried...

Qualitative Comparison of North-American Procedures for Areawide Pedestrian Travel Measurement

Greene-Roesel, Ryan
Diógenes, Mara C.
Ragland, David R.
Lindau, Luis A.
2007

There is no standard system for estimating area-wide pedestrian volumes in the United States. As a result, pedestrian volumes cannot be routinely used to guide transportation investments and monitoring measures performance. Vehicle volumes, by contrast, are measured systematically in each state and are reported to the Federal Highway Administration annually to be used in the allocation of federal funds. This paper investigates the advantages and disadvantages of three approaches to the creation of a standard system of pedestrian volume measurement: direct sampling, survey methods, and...

Applying Safety Improvements to Fleet Vehicles

Cooper, Douglas L.
Sharafsaleh, Mohammad A.
Ragland, David R.
Begley, Loida
Kim, Yong Hee
Jin, Eui Jae
2007

The safety of both employees and the motoring public is of paramount importance to Caltrans, resulting in a continuing effort to improve the operating vehicle fleet. The potential safety changes that are the focus of this project are those that involve safety equipment enhancement over and above the original specifications for the vehicle or outside of the scope of the original equipment design or purpose, such as rear view backup video cameras. The motivation for this project was Division of Equipment (DOE) managers' need for an objective strategy to address safety equipment deployment...

Attributable risk of alcohol and other drugs for crashes in the transit industry

Cunradi, Carol B.
Ragland, David R.
Greiner, Birgit A.
Klein, M.
Fisher, June M.
2005

Objective: To estimate the impact of employee alcohol and drug use on crashes in the transit industry from 1995–2000.

Design: Secondary analysis of federally mandated post crash and random alcohol and drug testing results.

Setting: The US transit industry.

Subjects: Transit industry employees.

Main outcome measures: Relative risk (RR), population attributable risk (PAR), and population attributable risk percentage (PAR%).

Results: For alcohol testing, the estimated PAR% ranged...

Physical workload, ergonomic problems, and incidence of low back injury: A 7.5-year prospective study of San Francisco transit operators

Krause, Niklas
Rugulies, Reiner
Ragland, David R.
Syme, S. Leonard
2004

Background: The etiologic role of biomechanical factors for low back injury (LBI) needs to be confirmed in prospective studies that control for psychosocial factors.

Methods: Complete baseline information on 1,233 vehicle operators was gathered during medical examinations and by questionnaire. First LBI during 7.5 years of follow-up was ascertained from insurance records. Hazard ratios and etiologic fractions were analyzed with Cox regression models stratified by injury severity and controlling for age, sex, height, weight, ethnicity, and biomechanical and...

Observations of Driver Time-Gap Acceptance at Intersections in Left-Turn Across-Path Opposite-Direction Scenarios

Chan, Ching-Yao
Ragland, David R.
Shladover, Steven E.
Misener, James A.
Marco, David
2005

Intersection collision warning systems can potentially reduce the number of collisions and associated losses. A critical design aspect of these systems is the selection of warning criteria, which represent a set of conditions and parameters under which the decision and the timing to issue warnings are determined. Proper warning criteria allow the generation of timely signals for drivers while minimizing false and nuisance alarms. We describe the development of a methodology to observe and analyze the selection of time gaps exhibited by driver behaviors in a real-world setting. The data...

Pedestrian Counting Methods at Intersections: a Comparative Study

Diogenes, Mara Chagas
Greene-Roesel, Ryan
Arnold, Lindsay S.
Ragland, David R.
2007

Resources for implementing countermeasures to reduce pedestrian collisions in urban centers are usually allocated on the basis of need, which is determined by risk studies. They commonly rely on pedestrian volumes at intersections. The methods used to estimate pedestrian volumes include direct counts and surveys, but few studies have addressed the accuracy of these methods. This paper investigates the accuracy of three common counting methods: manual counts using sheets, manual counts using clickers, and manual counts using video cameras. The counts took place in San Francisco. For the...

Occupational stressors and hypertension: A multi-method study using observer-based job analysis and self-reports in urban transit operators

Greiner, Birgit A.
Krause, Niklas
Ragland, David R.
Fisher, June M.
2004

This multi-method study aimed to disentangle objective and subjective components of job stressors and determine the role of each for hypertension risk. Because research on job stressors and hypertension has been exclusively based on self-reports of stressors, the tendency of some individuals to use denial and repressive coping might be responsible for the inconclusive results in previous studies. Stressor measures with different degrees of objectivity were contrasted, including (1) an observer-based measure of stressors (job barriers, time pressure) obtained from experts, (2) self-reported...

Alcohol, Stress-Related Factors, and Short-Term Absenteeism Among Urban Transit Operators

Cunradi, Carol B.
Greiner, Birgit A.
Ragland, David R.
Fisher, June M.
2005

Transit operators, relative to workers in many other occupations, experience high levels of work-related stress, as documented through neuroendocrine elevations on the job vis-à-vis resting states (J Occup Health Psychol. 1998;3:122–129). Previous research suggests that self-reported job stress is associated with higher levels of alcohol consumption among transit operators (Alcohol Clin Exp Res. 2000;24:1011–1019) and with absenteeism (Working Environment for Local...

On The Legal Deterrence Of Pedestrian Hit-and-Run Collisions

Grembek, Offer
Griswold, Julia B.
2012

Hit-and-run collisions—those in which a driver involved in the collision leaves the scene before the arrival of law enforcement officials—are a unique type of traffic violation because the driver's decision is a question of damage control rather than damage prevention. To reduce hitand-run violations, individual state laws impose legal sanctions to deter drivers from leaving the collision scene prematurely. Deterrence Theory dictates that compliance with laws is associated with the certainty, severity, and swiftness of punishment. The purpose of this study is to explore the deterrent...