Hotspot Analysis

Perceptions of Bicycle Safety: A Data and User-Experience Approach

August 30, 2022
New research brief explores the existing bicycle infrastructure in the City of Oakland as it relates to cyclist safety

Climate change has caused unprecedented problems, which has increased efforts to fund sustainable green alternatives, including funding for alternative means of transportation such as active transportation and micro-mobility infrastructure improvements. In a new research brief, Perceptions of Bicycle Safety: A Data and User-Experience Approach, UC Berkeley SafeTREC's Graduate Student Researcher Greg Harasym explores existing bicycle infrastructure in the...

SafeTREC at Transportation Research Board Annual Meeting 2020

January 31, 2020

This year SafeTREC faculty, staff and graduate students joined over 13,000 transportation professionals from around the world at the Transportation Research Board 99th Annual Meeting from January 16-20, 2020 in Washington, D.C. Our team had the opportunity to present some of our latest transportation safety research, participate in various events, workshops and activities, and connect with alum. Enjoy our round-up of selected photos to share what we were up to at #TRBAM!


Street Story Pilot

June 22, 2018

Crash data is readily available and accessible for public use through government information databases. Crash data typically entails vehicle-related injuries and fatalities that were reported to police authorities. But what about unreported incidents--incidents that only require exchange of contact and insurance information, incidents that may not involve an injury or injuries that might not have been reported? As a way to understand perceptions and experiences of safety in communities, UC Berkeley SafeTREC is developing an online data tool that allows people to self-report...

Visualizing Teen Driver Safety Needs: SafeTREC researchers present at 2017 GIS Day

November 10, 2017

Teen Heat Map Presentation

State Superintendent of Public Instruction, Tom Torlakson, with staff from the California Department of Education, California Office of Traffic Safety and SafeTREC.

On November 2, 2017, SafeTREC co-director Jill Cooper and researchers SangHyouk Oum and Liwei Fu presented SafeTREC’s latest data and mapping analysis tool, the Teen Safety Heat Map at the 2017 Geographic Information Systems...

Strategies for Reducing Pedestrian and Bicyclist Injury at the Corridor Level

Ragland, David R.
Grembek, Offer
Orrick, Phyllis

Methods for identifying sites with potential for preventing traffic fatalities and injuries have been developed for vehicle-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 from 1998-2007 from a 16.5-mile section of San Pablo Avenue (SR 123) in the San Francisco East Bay was used as a study area. Several approaches for identifying sites with high potential for reducing pedestrian and bicyclist injury were...

A Comparative Analysis of Pedestrian and Bicyclist Safety Around University Campuses

Grembek, Offer
Medury, Aditya
Orrick, Phyllis
Leung, Katherine
Ragland, David R.
Loukaitou-Sideris, Anastasia
Resnick, Justin
Wong, Norman
Shafizadeh, Kevan
Khan, Ghazan

Large college campuses generate considerable volumes of traffic in a variety of modes, and in greater numbers, than found in most U.S. settings. This setting presents a unique study opportunity, as well as a significant potential for conflicts between motorized and non-motorized users of the transportation system, surrounded as most campuses are by mixed-use environments e.g. retail, restaurant, entertainment and high-density residential facilities such as apartments and dorms. At the same time, university campuses are also typically characterized by a central core area where most trips...

Safety Assessment of Uncontrolled Intersections Using Both Conflict Probability and Severity

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

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...

Identification of Freeway Secondary Accidents with Traffic Shock Wave Detected by Loop Detectors

Wang, Junhua
Xie, Wenjing
Liu, Boya
Fang, Shou'en
Ragland, David R.

Secondary traffic accidents are generally recorded without being specifically noted as such in the accident database, leading to difficulty in the study of such accidents. Previous research generally classified secondary incidents by predefining fixed spatio-temporal boundaries—a method that can be very subjective. Using 10,762 accident records gathered from 2012 upstream loop detector data on a California interstate freeway, this paper proposes a dynamic method for more convincing and accurate classification based on traffic shock waves detected by the loop detectors. This method...

A Multidimensional Clustering Algorithm for Studying Fatal Road Crashes

Fishbain, Barak
Grembek, Offer

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...

Evaluating the Performance of Network Screening Methods for Detecting High Collision Concentration Locations on Highways

Kwon, Oh Hoon
Park, Min Ju
Yeo, Hwasoo
Chung, Koohong

This paper documents findings from evaluating performances of three different methods for segmenting freeway sites for the purpose of identifying high collision concentration locations: Sliding Moving Window (SMW), Peak Searching (PS) and Continuous Risk Profile (CRP). The traffic collision data from sites segmented in each method under two different roadway definitions were used to estimate excess expected average crash frequency with Empirical Bayes adjustment with respect to two different sets of Safety Performance Functions (SPFs). The estimates from each of the methods were then used...