Motorized Vehicle Safety

The Inclusion of Adult Vehicle Occupants in Matched Cohort Studies of Child Restraint Effectiveness: A Study of Potential Bias

Rice, Thomas M.
Anderson, Craig L.

Objective: To determine whether either the inclusion of adults in matched cohort studies of passenger vehicle occupants or modification of age effects by collision severity biases child restraint risk ratios biases estimate of child restraint effectiveness.

Methods: Monte Carlo data simulations were conducted to represent 10,000 collision-involved vehicles carrying a mix of children and adults. The effects of age category, adult seat belt use, child seat belt use, and child safety seat use were set to known values. Age was a modifier of the adult and child seat belt risk ratios and...

Alcohol Consumption and Incidence of Workers' Compensation Claims: A 5-Year Prospective Study of Urban Transit Operators

Ragland, David R.
Krause, Niklas
Greiner, Birgit A.
Holman, Barbara L.
Fisher, June M.
Cunradi, Carol B.

Numerous studies have linked alcohol impairment on the job to occupational injury. Few studies have looked at the association of nonwork drinking and occupational injury. This study examines first workers' compensation claims after a baseline assessment of alcohol consumption and other occupational variables in 1836 transit operators participating in a medical examination for driver's license renewal. A proportional hazard model was used for the analysis.

Individuals with higher alcohol consumption were more likely to be male, have more years of driving, and have a higher job-...

Traffic Volume and Collisions Involving Transit and Nontransit Vehicles

Ragland, David R.
Hundenski, Ronald J.
Holman, Barbara L.
Fisher, June M.

This study reports an analysis of collisions occurring between public transit vehicles operated by the San Francisco Municipal Railway System (Muni), the public transit agency for the City of San Francisco, and nontransit vehicles. The analysis, focusing on weekday collisions during 1987, demonstrated a strong association between hourly transit collisions rates and hourly traffic volume. The collision rate varied from 0.01 per 1,000 Muni vehicle-hours of operation during the interval 5 a.m. to 6 a.m., a time of very low traffic...

Objective Stress Factors, Accidents, and Absenteeism in Transit Operators: A Theoretical Framework and Empirical Evidence

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

The authors used observational job analysis as a conceptually based technique to measure stress factors unbiased by worker appraisal with 81 transit driving tasks on 27 transit lines. Stressor dimensions included work barriers that interfere with task performance due to poor technical-organizational design, time pressure, time binding (autonomy over time management), and monotonous conditions. Line-specific average stressor values were assigned to 308 transit operators who mainly worked the particular line. Logistic regression analyses showed associations for high work barriers and...

Automated Assessment of Safety-Critical Dynamics in Multi-modal Transportation Systems

Medury, Aditya
Yu, Mengqiao
Bourdais, Cedric
Grembek, Offer

Recent mobility trends reveal that travel is becoming increasing multi-modal in nature. Given the increase in the emphasis on multi-modal mobility there is a need to efficiently account for the multi-modal safety challenges it introduces. In light of this, it is of immense concern that the corresponding improvements made to traffic safety have not been commensurate across all modes. In this regard, one of the major challenges associated with efficiently designing and planning for a safe multi-modal environment is a limited understanding of multi-modal traffic behavior as explained by...

Do All Roadway Users Want the Same Things?

Sanders, Rebecca L.
Cooper, Jill F.

This paper presents findings from a recent study on roadway design preferences among pedestrians, drivers, bicyclists, and public transit users along a major urban corridor in the East San Francisco Bay Area. Sponsored by the California DOT, the research focused on exploring design preferences that could increase perceived traffic safety, walkability, bikability, and economic vitality along urban arterials. Results from an intercept survey showed that all user groups desire similar roadway design features along the test corridor, which carries 25,000-30,000 motorists bi-directionally...

Teens and Driving in California: Summary of Research and Best Practices

Bui, Huong
Arnold, Lindsay S.
Cooper, Jill F.
Ragland, David R.

The purpose of this guide is to present the major risk factors associated with teen driving in California and to highlight policy and program strategies that may be influential in reducing risk.

Driver Behavior at Rail Crossings: Cost-Effective Improvements to Increase Driver Safety at Public At-Grade Rail-Highway Crossings in California

Cooper, Douglas L.
Ragland, David R.

This report examines conditions affecting vehicle-train collisions at rail crossings in California, and recommends effective countermeasures and implementation strategies. In doing so, the report helps meet California’s goal of efficiently utilizing state and federal funding available through SAFETEA-LU for increasing the safety at public atgrade rail-highway crossings.

California Intersection Decision Support: A Systems Approach to Achieve Nationally Interoperable Solutions

Chan, Ching-Yao
Cody, Delphine
Cohn, Theodore
Dickey, Susan
Greenhouse, Dan
Mak, Tony
Marco, David
Nguyen, Khoi
Misener, James A.
Nowakowski, Christopher
Ossenbrugen, Paul
Ragland, David R.
Shladover, Steven E.
Tan, Swe-kuang
Vanderwerf, Joel
Wang, Xiqin
Zabyshny, Aleksandr
Zennaro, Marco

The overall IDS research plan was constructed to realize, in slightly more than three years, the requirements, tradeoffs assessment, and technology investigations necessary to define an IDS. Toward the end of the project we will combine our understanding of the problem definition, IDS technologies and our integration experience with a standard Caltrans intersection (with advanced controller) and design a deployable IDS demonstration that can be field tested.

Vehicle Occupancy and Crash Risk

Geyer, Judy A.
Ragland, David R.

This study explores the association between vehicle occupancy and a driver’s risk of causing a fatal crash, not wearing a seatbelt, and using alcohol. The survey population is the set of drivers represented in the Fatal Analysis Reporting System (FARS) (years 1992 to 2002). The independent variables are driver age, driver gender, passenger age, passenger gender, and vehicle occupancy. The outcome variables are whether the driver was at fault in causing the fatal crash, whether the driver wore a seatbelt, and whether the driver had been using alcohol. For male teenager drivers, driving with...