Rail Crossings: A Strategy to Select Countermeasure Improvements for Rail-Highway Crossings in California

Cooper, Douglas L.
Ragland, David R.

Rail crossing crashes have declined in the past 30 years, both nationally and in California. This is largely attributed to the closing of a large number of crossings as well as the deployment of a wide range of countermeasures, including signal systems, gating and grade separation programs. However, the number of crashes and subsequent injuries and deaths is still unacceptably high. Rail crossings provide different levels of warnings from four-quadrant gates down to stop signs. To understand how the state of California can best utilize state and federal funding available through SAFETEA-LU...

HOV Lane Configurationsand Collision Distribution on Freeway Lanes – An Investigation of Historical Collision Data in California

Chung, Koohong
Chan, Ching-Yao
Jang, Kitae
Ragland, David R.
Kim, Yong-Hee

High-Occupancy Vehicle (HOV) lane programs are widely adopted in metropolitan areas in an effort to reduce congestion by encouraging carpooling. However, the operation of HOV lanes may result in traffic interactions that affect safety performance. In this paper, historical data from a number of freeway corridors in California are used to illustrate the distribution of collisions on different lanes on the freeway. The peak hours’ data, when compared to those in the non-peak hours, from all corridors indicate that more interactions due to traffic weaving near the HOV lanes might lead to a...

A 3D Computer Simulation Test of the Leibowitz Hypothesis

Barton, Joseph E.
Cohn, Theodore E.

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...

Evaluation of Countermeasures: A Study on the Effect of Impactable Yield Signs Installed at Intersections in San Francisco

Banerjee, Ipsita
Ragland, David R.

The present study evaluated the effect of impactable signs that used the yield-symbol as approved by the National Committee on Uniform Traffic Control Devices (NCUTCD) in the 2003 Manual of Uniform Traffic Control Devices (MUTCD). Impactable yield signs are low-cost signs constructed of flexible material. The signs were installed in the medians adjacent to crosswalks at selected non-signalized intersections to instruct drivers to yield the right-of-way to pedestrians. This paper examines the effect on safety characteristics of the intersections of these signs at three stop-sign controlled...

Child Restraint Use: Workbook and Guide for Evaluating Community-based Programs

Ragland, David R.
Geyer, Judy A.
Cooper, Jill F.

The leading cause of injury and death for children in California is motor vehicle crashes. To prevent these needless tragedies, the California Office of Traffic Safety (OTS), through the Business, Transportation and Housing Agency, funds child passenger safety programs throughout the state. This workbook is designed to be used by these local programs to 1) evaluate the impact of their activities on child restraint use, 2) evaluate results to improve or modify the programs as needed, and 3) meet contractual evaluation requirements. Program evaluations can be difficult for local programs due...

Relative Burden of Distracted Driving Fatalities by Characteristic

Griswold, Julia B.
Grembek, Offer

We were glad to see discussion of the dangers of distracted driving to vulnerable road users in the article by Stimpson et al. in the November/December 2013 issue of Public Health Reports. However, we question the conclusion that pedestrian and bicyclist victims of distracted driving crashes are disproportionately nonHispanic white. This inference appears to be drawn from the results in Table 1 of the article, where the rates are calculated per one million total population, which fails to account for the different sizes of the populations of each race/ethnicity. To correctly evaluate the...

Keeping Children Safe in Cars

Cooper, Jill F.

Low-income children face twice the risk of dying from crash-related injuries compared to children from higher income families. To increase safety for these children, the California Health Care Safety Net Institute and the UC Davis Medical Center launched the Child Passenger Safety (CPS) Initiative with funding from the California Office of Traffic Safety. The initiative ran from April, 2001, through September, 2003, and had these goals: to increase safety seat use among families using public health care services; to decrease the rate of safety seat misuse among these families; and to...

Exploring Factors Influencing Bicyclists’ Perception of Comfort on Bicycle Facilities

Li, Zhibin
Wang, Wei
Zhang, Yuanyuan
Lu, Jie
Ragland, David R.

The primary objective of this study is to investigate the physical environmental factors influencing bicyclists‟ perception of comfort on physically separated bicycle paths and on-street bicycle lanes. We also look extensively at comparing the perception of comfort and the contributing factors between the two facility types. Field investigations were conducted at 43 segments on bicycle facilities in the metropolitan area of Nanjing, China. Bicyclists‟ perception of comfort and various environmental conditions were collected. We used an ordered probit (OP) model to analyze the data. Data...

Quantifying the Performance of Countermeasures for Collision Concentration Related to Ramp/Freeway Mainline Junctions

Lee, Joon Ho
Chan, Ching-Yao
Ragland, David R.

This study performed before-and-after analyses (comparisons of collisions before and after the construction of auxiliary lanes) on collision rate at nine study sites in California in order to achieve two objectives: (i) to estimate the freeway Crash/Collision Reduction Factor (CRF) for auxiliary lanes, and (ii) to develop design guidelines for the construction of auxiliary lanes. Findings indicate that on average, collision rates decreased by 17.3 percent at nine study sites. The study also found that after construction of auxiliary lanes at two study sites, collision rates increased when...

Identifying Factors that Determine Bicycle and Pedestrian-Involved Collision Rates that Affect Bicycle and Pedestrian Demand at Multi-Lane Roundabouts

Arnold, Lindsay S.
Flannery, Aimee
Ledbetter, Lauren
Bills, Tierra
Jones, Michael G.
Ragland, David R.
Spautz, Laura

This project examined the safety and demand issues for pedestrians and bicyclists at multi-lane roundabouts through a literature review, case studies, in-field counts and surveys, focus groups, and video analysis. This document presents research findings, synthesizes current information on best practices, and makes recommendations to assist local agencies planning and designing safer multi-lane roundabouts. These findings should help local agencies and Caltrans create roundabouts that better and more safely address the needs of bicyclists and pedestrians. The current literature is referred...