Road User Behavior

Estimating Pedestrian Accident Exposure: Automated Pedestrian Counting Devices Report

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

Automated methods are commonly used to count motorized vehicles, but are not frequently used to count pedestrians. This is because the automated technologies available to count pedestrians are not very developed, and their effectiveness has not been widely researched. Moreover, most automated methods are used primarily for the purpose of detecting, rather than counting, pedestrians (Dharmaraju et al., 2001; Noyce and Dharmaraju, 2002; Noyce et al., 2006). Automated pedestrian counting technologies are attractive because they have the potential to reduce the labor costs associated with...

Integration of Light Rail Transit into City Streets

Korve, Hans W.
Farran, Jose I.
Mansel, Douglas M.
Levinson, Herbert S.
Chira-Chavala, T.
Ragland, David R.
1996

This report addresses the safety and operating experience of light rail transit (LRT) systems operating in shared (on-street or mall) rights-of-way at speeds that do not exceed 35 mph. It is based on agency interviews, field observations, and accident analyses of 10 LRT systems in the United States and Canada. These systems—in Baltimore, Boston, Buffalo, Calgary, Los Angeles, Portland, Sacramento, San Diego, San Francisco, and San Jose—provide a broad range of current LRT operating practices and problems.

The report provides information to facilitate the safe, orderly, and...

Relative Vulnerability Matrix for Evaluating Multimodal Traffic Safety

Grembek, Offer
2015

The multimodal transportation network includes a mix of inherently different modes. In addition to differences in price, range, and comfort of travel, these modes differ in mass and velocity, which correspond to different orders of magnitude in the kinetic energy carried. This discrepancy in kinetic energy affects both the level of protection of each mode, and the level of damage it can inflict on users of other modes. Unfortunately, accounting for both sides of a crash is often overlooked. While the quantities and variables of collected data continue to increase, the analyses conducted...

Using Variable Speed Limits To Reduce Rear-End Collision Risks Near Recurrent Bottlenecks

Li, Zhibin
Liu, Pan
Bigham, John M.
Ragland, David R.
2013

Rear-end collisions would occur if vehicle speeds decrease abruptly when encountering kinematic waves (KWs) emanating from active bottlenecks. This study aims to develop a control strategy in variable speed limits (VSL) to reduce rear-end collision risks near recurrent bottlenecks. Using the crash prediction model developed for rear-end collisions related to risky KWs, the effectiveness of VSL control strategies were evaluated in the cell transmission model (CTM). Several strategies were tested in sequence to determine the best case for risk reduction. Results of this study show that the...

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...

Associations between Road Network Structure and Pedestrian-Bicyclist Accidents

Zhang, Yuanyuan
Bigham, John M.
Li, Zhibin
Ragland, David R.
Chen, Xiaohong
2012

It is widely known that the road network layout can impact the non-motorized users’ traffic safety by changing the non-motorized traffic volume and road users’ behavior. Different road network patterns lead to different traffic safety levels for non-auto users and a single pattern can even have both the safe and unsafe features at the same time. By knowing what features can lead to safer traffic environment, existing road networks can be improved and new network patterns can be produced by combining all safe features from different patterns. Therefore, the associations between road network...

Using Time-Based Metrics to Compare Crash Risk Across Modes and Locations

Guler, S. Ilgin
Grembek, Offer
Ragland, David R.
2012

The objective of this work is to identify better metrics of exposure when comparing traffic crash risk across modes or across locations. We propose that total time travelled should be used for road user exposure to crash risk. The idea behind this is that travel time reflects the differences in speeds across different modes and hence should be used as the basic exposure metric from which crash risk based on other metrics, such as travel distance, can easily be derived. We also propose that when comparing crash risk of different modes across different locations the time-based mode share...

Safety Assessment of Uncontrolled Intersections Using Both Conflict Probability and Severity

Ma, Yingying
Qin, Xiaoran
Grembek, Offer
Chen, Zhiwei
2016

This paper presents a method to assess the safety of uncontrolled intersections considering both conflict probability and severity, which are two major properties of traffic conflicts. This method provides not only the safety level of the entire intersection but also the distribution of safety within intersections. Intersections are modelled by a two-dimensional Cartesian coordinate system and the internal space of intersections is divided into cells. Firstly, vehicle movement characteristics of at uncontrolled intersections are modelled. Secondly, conflict probability of each cell within...

Modeling Secondary Accidents Identified by Traffic Shock Waves

Wang, Junhua
Liu, Boya
Lanfang, Zhang
Ragland, David R.
2015

The high potential for occurrence and the negative consequences of secondary accidents make them an issue of great concern affecting freeway safety. Using accident records from a three-year period together with California interstate freeway loop data, a dynamic method for more accurate classification based on the traffic shock wave detecting method was used to identify secondary accidents. Spatio-temporal gaps between the primary and secondary accident were proven be fit via a mixture of Weibull and normal distribution. A logistic regression model was developed to investigate major factors...

Recommendations to Improve Pedestrian Safety in the Town of Paradise

Dang, Tony
Alfsen, Wendy
2013

In response to the recent death of a Paradise youth who was struck on Skyway Road, the Town of Paradise invited California WALKS to facilitate a workshop providing community residents, Town staff members, and other professionals with an overview of pedestrian safety best practices, to conduct a walkability assessment of areas near the downtown core, and to lead small group discussions to develop specific recommendations for Town Council to improve the safety and walkability of Paradise. This report summarizes overall walkability and pedestrian safety observations of downtown Paradise, as...