Road User Behavior

Transportation and Health: Policy Interventions for Safer, Healthier People and Communities

Ragland, David R.
Orrick, Phyllis
2011

The public road system in the U.S. is the world’s busiest, sustaining more than 3 trillion vehiclemiles of travel each year on a network of more than 4 million miles of roads and highways. It has had enormous positive impacts on U.S. society, driving economic growth and innovation, providing mobility and opportunity to its users, and helping the U.S. maintain its global economic competitiveness. This system was built with a focus on motor vehicles; only recently has substantial funding and attention been given to transit, walking, and bicycling. There is still a huge disparity in how we...

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

Mitman, Meghan F.
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...

Driving Cessation and Increased Depressive Symptoms

Ragland, David R.
Satariano, William A.
MacLeod, Kara E.
2003

Background. To understand the consequences of driving cessation in older adults, the authors evaluated depression in former drivers compared with active drivers.

Methods. Depression (as assessed using the Center for Epidemiological Studies Depression Scale), driving status, sociodemographic factors, health status, and cognitive function were evaluated for a cohort of 1953 residents of Sonoma County, California, aged 55 years and older, as part of a community-based study of aging and physical performance. The authors reinterviewed 1772...

Problems With Vision Associated With Limitations or Avoidance of Driving in Older Populations

Satariano, William A.
MacLeod, Kara E.
Kohn, Theodore E.
Ragland, David R.
2004

Objectives. This report examines the role of (a) disease processes affecting vision, (b) reported troubles with vision, (c) physical symptoms affecting the eyes, and (d) objective measures in reported driving limitation due to problems with eyesight among older drivers.

Methods. Data for this study (N 1⁄4 1,840) were obtained from participants in a community-based study of aging and physical performance in people age 55 or older in the city of Sonoma, California. Each of 16 visual conditions was...

HOV Lane Configurations and Safety Performance of California Freeways – An Investigation of Differential Distributions and Statistical Analysis

Jang, Kitae
Chan, Ching-Yao
2009

From a recent study of safety evaluation of HOV-equipped freeways, it was found that limited- access HOV lanes appear to have a safety performance disadvantage when measured by collision distribution or collision rates for the HOV lane alone and for the HOV and left lanes combined. This paper describes the work performed to verify the statistical significance of related findings. Several statistical tests were used: empirical cumulative density function (CDF), Kolmogorov-Smirnov Tests, and comparison of means based on Poisson Distributed Samples. The conclusion that continuous-access...

Association between Roadway Intersection Characteristics and Pedestrian Crash Risk in Alameda County, California

Schneider, Robert J.
Diogenes, Mara Chagas
Arnold, Lindsay S.
Attaset, Vanvisa
Griswold, Julia B.
Ragland, David R.
2010

Each year from 1998 to 2007, an average of approximately 4,800 pedestrians were killed and 71,000 pedestrians were injured in United States traffic crashes. Because many pedestrian crashes occur at roadway intersections, it is important to understand the intersection characteristics that are associated with pedestrian crash risk. This study uses detailed pedestrian crash data and pedestrian volume estimates to analyze pedestrian crash risk at 81 intersections along arterial and collector roadways in Alameda County, California. The analysis compares pedestrian crash rates (crashes per 10,...

Identification of High Collision Concentration Locations Under Wet Weather Conditions

Hwang, Taesung
Chung, Koohong
Ragland, David R.
Chan, Chin-Yao
2008

This paper focuses on identifying roadway locations that display high collision rates only under wet pavement condition. A unique approach of screening and identifying such locations, called the continuous risk profile (CRP) method, was utilized for this analysis. The CRP method was applied to over 380 miles of freeways in the San Francisco Bay Area to identify sites that display high collision rates only under wet pavement condition. Twelve of the identified sites were then further investigated to determine if there are any common geometric, topographic, or site conditions that may...

Addressing Inappropriate Driver Behavior at Rail-Highway Crossings

Cooper, Douglas L.
Ragland, David R.
2008

Driver behavior at rail highway crossings has been the subject of numerous studies, most of which show that violations are relatively commonplace. The focus of this paper will be on those drivers who drive around fully descended gates. Drivers commonly misjudge the speed and distance of trains. They must make a decision about the time remaining before the train arrives based on sensory signals as well as non-sensory factors such as expectations and motivation. At a gated crossing, where drivers have been alerted to the imminent danger by lowered gates, there is more to be gained by...

Estimating Bicycle and Pedestrian Demand in San Diego

Jones, Michael
Buckland, Lauren
2008

This paper introduces the concepts behind estimating bicycle and pedestrian demand and provides an example of the development of a sketch-plan method for estimating bicycle and pedestrian demand from land use in San Diego County. The paper describes the methodology involved in collecting counts for the currently ongoing Seamless Travel project. The Seamless Travel project intends to develop a model for estimating bicycle and pedestrian demand within San Diego County. The project methodology includes conducting bicycle and pedestrian counts and intercept surveys over a two-year period...

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)...