Countermeasures

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
2005

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.

An Intensive Pedestrian Safety Engineering Study Using Computerized Crash Analysis

Ragland, David R.
Markowitz, Frank
MacLeod, Kara E.
2003

Over the past year, the San Francisco Department of Parking and Traffic (DPT) conducted an intensive pedestrian-safety engineering study, the PedSafe Study. PedSafe was funded by the Federal Highway Administration (FHWA)*, which also funded companion studies in Las Vegas and Miami. The study was designed to analyze pedestrian injuries by zones (i.e., neighborhoods or districts) and to identify those most amenable to prevention efforts. The DPT expects to utilize the methodology and information from the PedSafe study to help shape a citywide pedestrian master plan. This paper describes the...

Intersection Decision Support Project: Taxonomy of Crossing-Path Crashes at Intersections Using GES 2000 Data

Ragland, David R.
Zabyshny, Aleksandr
2003

The Intersection Decision Support (IDS) Project is designed to reduce crossing-path (CP) crashes at intersections by providing crucial information to drivers that would help them avoid such crashes. Over the past decade, researchers have used the General Estimates System (GES, a representative sample of police-reported crashes in the US) and other data sources to develop a taxonomy of CP crashes and pre-crash scenarios as groundwork for crash-prevention efforts. The current study builds on and extends prior work by constructing a taxonomy of CP crashes using data from the 2000 GES and...

Driver/Pedestrian Understanding and Behavior at Marked and Unmarked Crosswalks

Mitman, Meghan F.
Ragland, David R.
2008

Pedestrian injuries at crosswalk locations represent a significant problem. In 2002, 22.7 percent of US pedestrians involved in collisions were in a crosswalk at the time of the collision, and over 96% of these occurred at an intersection. Almost all crosswalk collisions resulted in pedestrian injury or fatality (98.6 percent), and about one-third resulted in severe or fatal injury (National Automotive Sampling System (NASS) and General Estimates System (GES) 2002). As the owner of the California State Highway System, Caltrans is responsible for providing access to safe and...

The Continuous Risk Profile Approach for the Identification of High Collision Concentration Locations on Congested Highways

Chung, Koohong
Ragland, David R.
Madanat, Samer
Oh, Soon Mi
2009

This paper documents a new method for monitoring traffic collision data from continuous roadway facilities to detect high collision concentration locations. Many existing methods for detecting collision concentration locations require segmentation of roadways and assume traffic collision data are spatially uncorrelated, resulting in both false positives (i.e., identifying sites for safety improvements that should not have been selected) and false negatives (i.e., not identifying sites that should have been selected). The proposed method does not require segmentation of roadways;...

Predictors of Nonstandard Helmet Use Among San Francisco Bay–Area Motorcyclists

Tsui, Casey K.
Rice, Thomas M.
Pande, Swati
2013
Objective: The use of helmets that do not comply with safety standards is common in California. The objective of this study was to describe the use of these nonstandard helmets among San Francisco Bay–area (SFBA) motorcyclists and to identify personal and motorcycle characteristics that are associated with the use of nonstandard helmets. Methods: A survey of 860 SFBA motorcyclists was conducted. Log-binomial regression was used to estimate risk ratios to compare probabilities of nonstandard helmet use. Results: Fifteen percent of motorcyclists reported wearing a nonstandard helmet sometimes...

Estimating Pedestrian Accident Exposure: Protocol Report

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

Walking is a healthful, environmentally benign form of travel, and is the most basic form of human mobility. Walking trips account for more than 8 percent of all trips taken in California, making walking the second most commonly used mode of travel after the personal automobile (Caltrans, 2002). In addition, many trips made by vehicle or public transit begin and end with walking.

In spite of the importance and benefits of walking, pedestrians suffer a disproportionate share of the harm of traffic incidents in California. As noted above...

Acceptance of drinking and driving and alcohol-involved driving crashes in California

MacLeod, Kara E.
Karriker-Jaffe, Katherine J.
Ragland, David R.
Satariano, William A.
Kelley-Baker, Tara
Lacey, John H.
2015

Background: Alcohol-impaired driving accounts for substantial proportion of traffic-related fatalities in the U.S. Risk perceptions for drinking and driving have been associated with various measures of drinking and driving behavior. In an effort to understand how to intervene and to better understand how risk perceptions may be shaped, this study explored whether an objective environmental-level measure (proportion of alcohol-involved driving crashes in one’s residential city) were related to individual-level perceptions and behavior.

Methods: Using data from a 2012 cross-sectional...

Strategies for Reducing Pedestrian and Bicyclist Injury at the Corridor Level

Grembek, Offer
Zhang, Yuanyuan
Yavari, Afsaneh
Yang, Zhao
Ragland, David R.
2013

A systemic approach for identifying potential safety countermeasures and implementing them across groups of locations sharing the same risk characteristics has been developed for pedestrian-vehicle collisions. This study was funded by the California Department of Transportation (Caltrans) to develop methods for identifying sites where there is potential for significant reductions in pedestrian and bicyclist injury. Data collected between 1998 and 2007 from a 16.5-mile section of San Pablo Avenue (SR 123) in the San Francisco East Bay was used as the study area. A database containing all...

Combining traffic efficiency and traffic safety in countermeasure selection to improve pedestrian safety at two-way stop controlled intersections

Yang, Zhao
Zhang, Yuanyuan
Grembek, Offer
2016

Decision makers are encouraged to consider multiple objectives (such as traffic efficiency, safety, and environment) together to make decisions. Although there are methods to evaluate each objective respectively, there are few reports or research papers showing how to incorporate these objectives and put it in practice. Thus, this study aims to develop a procedure to incorporate traffic efficiency into the traffic safety countermeasure (CM) selection process. To illustrate the procedure, the economic benefits of four pedestrian safety improvements at crosswalks of major-streets at two-way...