Road User Behavior

Drivers, Pedestrians, and Cyclists in California Want Complete Streets: Comparison of Results from Roadway Design Surveys of Pedestrians, Drivers, Bicyclists, and Transit Users in Northern and Southern California

Sanders, Rebecca L.
Griffin, Ashleigh
MacLeod, Kara E.
Cooper, Jill F.
2014

This paper compares findings from two recent surveys on roadway design preferences among pedestrians, drivers, bicyclists, and public transit users along major urban corridors in the metro areas of San Francisco and Los Angeles. Sponsored by the California Department of Transportation (DOT), the research explored design preferences that could increase perceived traffic safety, walkability, bikability, and economic vitality along urban arterials. Results from intercept surveys showed that roadway users desire similar design features along the test corridors, which carry 25,000-40,000...

Motor vehicle speed as a risk factor in pedestrian safety

McMillan, Tracy
Cooper, Jill F.
2019

Speed is a significant risk factor in road safety. Several recent reports from the National Transportation Safety Board (NTSB) and the Governors Highway Safety Administration (GHSA) highlight the need for a greater focus on speed management at the national, state and local level. As part of our Community Pedestrian and Bicycle Safety Program (CPBSP), UC Berkeley SafeTREC has prepared a new research brief, "Motor vehicle speed as a risk factor in pedestrian safety"...

California Traffic Safety Survey 2022

Ewald, Katrin
Wasserman, Lisa
2022

Ewald & Wasserman Research (E&W) conducted the 2022 California Traffic Safety Public Opinion Study on behalf of the California Office of Traffic Safety (OTS) and the Safe Transportation Research and Education Center of UC Berkeley (SafeTREC). Similar to previous years and since 2020, the data collection transitioned from an intercept survey to an online panel with survey panelists provided by Marketing Services Group, a commercial sample and panel vendor.

Panelists consisted of California drivers who were forwarded to an online survey portal programmed and managed by E&W...

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...

Developing Safety Management Tools for State Departments of Transportation

Chung, Koohong
Grembek, Offer
Lee, Jinwoo
Choi, Keechoo
2013

Two safety management tools have recently been developed for the California Department of Transportation (Caltrans). One is the continuous risk profile (CRP) approach, which is a network screening procedure, and the other is the California Safety Analyst (CASA), a web-based application designed to assist state safety engineers in conducting safety investigations and in documenting their findings. This paper provides a qualitative description of the two tools and summarizes feedback from more than 100 Caltrans safety engineers who attended demonstrations of the web-based application....

A Multidimensional Clustering Algorithm for Studying Fatal Road Crashes

Fishbain, Barak
Grembek, Offer
2014

Road fatalities are rare outcomes of events that occur in a small time-space region. Although the exact chain of events for each fatality is unique, there are inherent similarities between road fatalities. The science of road safety is dedicated to identifying such similarities, mainly using statistical analysis tools. Researchers typically analyze patterns that emerge over space, such as hot-spot studies, or patterns that emerge over time, such as before-after studies. Traffic research enumerates 84 parameters that characterize a road fatality. A vast number of papers have tried to...

Crosswalk Confusion: More Evidence Why Pedestrian and Driver Knowledge of the Vehicle Code Should Not Be Assumed

Mitman, Meghan F.
Ragland, David R.
2014

Traffic safety researchers have long argued that driver behavior outweighs physical elements (such as road design) as a causal factor in motor vehicle collisions. A fundamental causal component of pedestrian—vehicle collisions is also behavior: that of the driver and that of the pedestrian. One determinant of this behavior may be whether the driver, the pedestrian, or both understand the motor vehicle code, which demarcates the right-of-way in pedestrian-vehicle interactions. That is, inappropriate or unlawful behavior may occur because the law is not understood or is misunderstood....

Relative Burden of Distracted Driving Fatalities by Characteristic

Griswold, Julia B.
Grembek, Offer
2014

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...

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...

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...