Data collection

Driver and Pedestrian Behavior at Uncontrolled Crosswalks in the Tahoe Basin Recreation Area

Mitman, Meghan F.
Cooper, Douglas L.
DuBose, Brooke
2010

For more than thirty years, pedestrian safety studies have considered pedestrian-vehicle collision patterns and pedestrian and driver behavior at marked and unmarked crosswalks at uncontrolled crossings. Recent research in this area conducted by the UC Berkeley Traffic Safety Center [aka SafeTREC] on behalf of Caltrans, and summarized in a 2008 Transportation Research Record paper by Mitman et al., “The Marked Crosswalk Dilemma: Uncovering Some Missing Links in a 35-Year Debate,” was designed to fill key gaps in the literature by analyzing driver/pedestrian behavior and knowledge of...

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...

Reasons Given by Older People for Limitation or Avoidance of Driving

Ragland, David R.
Satariano, William A.
MacLeod, Kara E.
2002

Purpose: To understand the driving behavior of older adults, this study examines self-reported reasons for driving limitation or avoidance.Design and Methods: Baseline interviews were conducted (n = 2,046) as part of a community-based study of aging and physical performance in persons aged 55 years or older in Sonoma, California. Twenty-one medical and nonmedical reasons for limiting or avoiding driving were examined by age and gender. Results: Most older people continue...

Consequences of Driving Reduction or Cessation for Older Adults

Harrison, Ayodele
Ragland, David R.
2003

The purpose of this study was to understand the adverse consequences of driving reduction or cessation among elderly adults. A comprehensive literature search was conducted for studies that (a) included information on driving by an elderly population, (b) included results from a qualitative or quantitative (or both) study of the elderly and driving cessation, and (c) provided information to evaluate consequences surrounding driving reduction or cessation. The selected subjects of the studies included men...

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,...

Influential Factors on Level of Injury in Pedestrian Crashes: Applications of Ordered Probit Model with Robust Standard Errors

Jang, Kitae
Park, Shin Hyoung
Chung, Sungbong
Song, Ki Han
2010

Pedestrian-involved crashes that occurred in the city of San Francisco over a six-year period, 2002–2007, were analyzed to examine various influential factors on the injury severity of pedestrian crashes. The crash data extracted from the Statewide Integrated Traffic Records System (SWITRS) include five categorical levels of injury severity in traffic crashes also in addition to detailed information about the features of each crash. This study applied an ordered probit model for injury severity analysis to specify the ordinal nature of injury categories. To draw unbiased implications...

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...

Effectiveness of a Commercially Available Automated Pedestrian Counting Device in Urban Environments: Comparison with Manual Counts

Greene-Roesel, Ryan
Diogenes, Mara Chagas
Ragland, David R.
Lindau, Luis Antonio
2008

High-quality continuous counts of pedestrian volume are necessary to evaluate the effects of pedestrian infrastructure investments and to improve pedestrian volume modeling. Automated pedestrian counting devices can meet the need for continuous counts of pedestrian volume and reduce the labor cost associated with manual pedestrian counting and data entry. However, most existing automated pedestrian devices are not well suited to the task of counting pedestrians in outdoor environments, and little is known about their effectiveness and accuracy. This study addresses the lack of...