Roads/Highways

Urban Street Contexts Classification Using Convolutional Neural Networks and Streets Imagery

Alhasoun, Fahad
González, Marta
2019

The classification of streets on road networks has been focused on the vehicular transportational features of streets. Examples of street labels include arterials, major roads, minor roads and so forth based on their transportational use. City authorities on the other hand have been shifting to more wholistic planning of streets. The modern approach towards designing and planning streets is more inclusive of the street context, meaning the side use of a street combined with the transportational features of a street. Several city authorities are developing new classification schemes for...

Streetify: Using Street View Imagery And Deep Learning For Urban Streets Development

Alhasoun, Fahad
González, Marta
2019

The classification of streets on road networks has been focused on the vehicular transportational features of streets such as arterials, major roads, minor roads and so forth based on their transportational use. City authorities on the other hand have been shifting to more urban inclusive planning of streets, encompassing the side use of a street combined with the transportational features of a street. In such classification schemes, streets are labeled for example as commercial throughway, residential neighborhood, park etc. This modern approach to urban planning has been adopted by major...

On the capacity of isolated, curbside bus stops

Gu, Weihua
Li, Yuwei
Cassidy, Michael J.
Griswold, Julia B.
2011

The maximal rates that buses can discharge from bus stops are examined. Models were developed to estimate these capacities for curbside stops that are isolated from the effects of traffic signals. The models account for key features of the stops, including their target service levels assigned to them by a transit agency. Among other things, the models predict that adding bus berths to a stop can sometimes return disproportionally high gains in capacity. This and other of our findings are at odds with information furnished in professional handbooks.

Limitations of Data on Cell Phone Involvement in Collisions: A Case Study of California

Griswold, Julia B.
Grembek, Offer
2014

With the increasing prevalence of mobile technology and high-profile crashes bringing attention to distracted driving, data on cell phone involvement in collisions is critical for understanding the extent of the problem, examining the effectiveness of policies, and developing interventions to improve safety. Some limitations of existing data have been previously identified, but this paper examines the specific case of California’s collision data. Temporal, geographic, and jurisdictional trends are analyzed to identify the source and type of inconsistencies in the cell phone involvement...

Evaluate the Safety Effects of Adopting a Stop-as-Yield Law for Cyclists in California

Mahdinia, Iman
Griswold, Julia B.
Unda, Rafael
Sohrabi, Soheil
Grembek, Offer
2024

The escalating number of injuries and fatalities among cyclists is a pressing safety concern. In the United States, communities are actively seeking strategies to boost cyclist safety, with some states implementing bike-specific policies, such as stop-as-yield laws, to support cyclists. Stop-as-yield laws allow cyclists to treat stop signs as yield signs. The laws are not yet widely implemented, and their potential safety impact is a subject of debate among transportation experts and advocates. This study investigates how stop-as-yield laws can positively or negatively affect safety and...

Developing a Safe System Approach to Setting Speed Limits

Griswold, Julia B
Lutzker, Liza
Fournier, Nicholas
Grembek, Offer
Fox, Jenn
Shahum, Leah
University of California, Berkeley
Vision Zero Network
2023

Over the last decade in California there has been a surge in the number of traffic fatalities, with especially large increases in pedestrian fatalities. At the same time, the California Department of Transportation (Caltrans) has affirmed a vision of reaching zero fatalities and serious injuries on state highways by 2050 and has committed the department to reaching this goal by adopting the Safe System Approach. The Safe System Approach is underpinned by the principles that humans make mistakes and that the transportation system should be designed to account for the human body’s ability to...

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
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 traffic crashes in the United States. Because many pedestrian crashes occur at roadway intersections, it is important to understand the intersection characteristics that are associated with pedestrian crash risk. The present study uses detailed pedestrian crash data and pedestrian volume estimates to analyze the pedestrian crash risk at 81 intersections along arterial and collector roadways in Alameda County, California. The analysis compares pedestrian crash rates...

ArcGIS GDB for CPBS Report 23UCB01 - A Context-sensitive Street Classification Framework for Speed Limit Setting

Safety Center for Pedestrian and Bicyclist
2024

ArcGIS .gdb geodatabase files and a data dictionary in Excel format.

A Pedestrian Exposure Model for the California State Highway System

Griswold, Julia B.
Medury, Aditya
Schneider, Robert J.
Amos, Dave
Li, Ang
Grembek, Offer
2019

For this study, we developed one of the first statewide pedestrian exposure models, using log-linear regression to estimate annual pedestrian crossing volumes at intersections on the California State Highway System. We compiled a database of more than 1,200 count locations, one of the largest ever used to create a pedestrian volume mode. We initially evaluated 75 explanatory variables for the model. The final model is based on the three land-use variables (employment density, population density, number of schools), four roadway network variables (number of street segments, intersections...

A behavioral modeling approach to bicycle level of service

Griswold, Julia B.
Yu, Mengqiao
Filingeri, Victoria
Grembek, Offer
Walker, Joan L.
2018

Bicycle level of service (LOS) measures are essential tools for transportation agencies to monitor and prioritize improvements to infrastructure for cyclists. While it is apparent that different types of cyclists have varying preferences for the facilities on which they ride, in current research and practice, measures are used that are either insufficiently quantitative and empirical or lack cyclist segmentation. In this study, we conducted a detailed survey on cyclist habits, preferences, and user experience, capturing responses to videos of a bicycle traveling on road segments in the San...