Data collection

Health Impacts of the School Commute

Lee, Murray
Orenstein, Marla
Richardson, Maxwell J.
Ragland, David R.
2008

A dramatic decline in walking and cycling to school has been observed in many geographic and cultural regions, and most children in the US are now driven to school in private vehicles. There are a number of health implications associated with the choice of commute mode, including traffic safety, exposure to air pollution, and levels of physical activity and obesity, and the risks and benefits of each must be weighed. This paper reviews current evidence on these risks and benefits for each health topic area. From a traffic safety perspective, buses are best, while the risks of private...

Estimating Bicycle and Pedestrian Demand in San Diego

Jones, Michael
Buckland, Lauren
2008

This paper introduces the concepts behind estimating bicycle and pedestrian demand and provides an example of the development of a sketch-plan method for estimating bicycle and pedestrian demand from land use in San Diego County. The paper describes the methodology involved in collecting counts for the currently ongoing Seamless Travel project. The Seamless Travel project intends to develop a model for estimating bicycle and pedestrian demand within San Diego County. The project methodology includes conducting bicycle and pedestrian counts and intercept surveys over a two-year period...

Comparison of collisions on HOV facilities with limited and continuous access

Jang, Kitae
Chung, Koohong
Ragland, David R.
Chan, Ching-Yao
2008

This paper describes comparisons of traffic safety during the morning and afternoon peak hours in extended stretches of eight High Occupancy Vehicle (HOV) lanes with two different types of access – four corridors with continuous access and the others with limited access. Traffic collision patterns in two different types of HOV lanes were investigated by evaluating 1) the differences in collision distribution, severity, types of collisions and per lane traffic utilization, 2) spatial distribution of collision concentrations by using Continuous Risk Profile (CRP) approach, and 3)...

San Francisco PedSafe II Project Outcomes and Lessons Learned

Hua, Jenna
Gutierrez, Nicolas
Banerjee, Ipsita
Markowitz, Frank
Ragland, David R.
2009

This paper presents the project outcomes and lessons learned from the San Francisco PedSafe, a comprehensive pedestrian safety planning and engineering project funded by the Federal Highway Administration. It assesses the effectiveness of the Phase I pedestrian safety plan targeted to higher-injury areas by evaluating the Phase II implementation of a range of mostly low-to- moderate-cost innovative safety improvements.

A total of 13 countermeasures (comprised of nine general engineering countermeasures and four Intelligent Transportation Systems (ITS)...

A Pilot Model for Estimating Pedestrian Intersection Crossing Volumes

Schneider, Robert J.
Arnold, Lindsay S.
Ragland, David R.
2009

Better data on pedestrian volumes are needed to improve the safety, comfort, and convenience of pedestrian movement. This requires more carefully-developed methodologies for counting pedestrians as well as improved methods of modeling pedestrian volumes. This paper describes the methodology used to create a simple, pilot model of pedestrian intersection crossing volumes in Alameda County, CA. The model is based on weekly pedestrian volumes at a sample of 50 intersections with a wide variety of surrounding land uses, transportation system attributes, and neighborhood socioeconomic...

Analysis of Wet Weather Related Collision Concentration Locations: Empirical Assessment of Continuous Risk Profile

Oh, Soonmi
Chung, Koohong
Ragland, David R.
Chan, Ching-Yao
2009

The objective of the study described in this paper is to identify common site features that may contribute to high collision rates under wet pavement conditions. To minimize falsely identified high collision concentration locations (HCCL) in evaluating factors contributing to high collision rate, this study accessed the magnitude of false positives (i.e., identifying sites for safety improvements that should not have been selected) by comparing HCCLs identified by the existing conventional sliding moving window approach with the ones identified by the Continuous Risk Profile (CRP)...

Safety Performance of High-Occupancy Vehicle (HOV) Facilities: Evaluation of HOV Lane Configurations in California

Jang, Kitae
Chung, Koohong
Ragland, David R.
Chan, Ching-Yao
2009

Collision data from High Occupancy Vehicle (HOV) facilities with two different types of access, continuous and limited, are examined in this paper. The findings show that HOV facilities with limited access offer no safety advantages over those with a continuous access. Compared with continuous access HOV lanes, a higher percentage of collisions was concentrated on limited access HOV lanes. Limited access HOV lanes also had higher collision rates. Findings from investigating the relationship between collision rates in HOV lanes with respect to shoulder width, length of access, and the...

Effects of Weather Variables on Pedestrian Volumes in Alameda County, California

Attaset, Vanvisa
Schneider, Robert J.
Arnold, Lindsay S.
Ragland, David R.
2010

Accurate estimates of pedestrian volume are important for analyzing pedestrian movement and safety; methods to estimate these volumes are continuously evolving and being improved. However, relatively little is known about the impact of weather conditions on pedestrian activity. This paper evaluates the effect of weather by including temperature, cloud cover, wind, and precipitation variables in a linear regression model of pedestrian volumes. Pedestrian volumes were collected over approximately one year using automated counters at 13 different locations in Alameda County, California...

A Methodology of Quantifying Precipitation Exposure for Wet-Weather Collisions and Evaluating Effectiveness of Open-Grade Asphalt Concrete as a CountermeasureWeather-related crashes represent a significant concern in roadway safety.

Chan, Ching-Yao
Jin, Eui-Jae
Oh, Soon Mi
Ragland, David R.
2010

Weather-related crashes represent a significant concern in roadway safety. Wet collisions often resulted in injuries or fatalities, at a ratio higher than collisions that occur in dry roadway conditions. Therefore, it is of strong interest to identify and manage the locations where collisions are prone to happen under wet pavement surface or adverse weather conditions. This paper introduces a method to estimate precipitation exposure of roadway segments by linking weather station data to collision database. Subsequently, the corresponding crash rate for a subject location is...

A Dynamic Congestion Pricing Strategy for High-Occupancy Toll Lanes

Jang, Kitae
Chung, Koohong
2010

High Occupancy Toll (HOT) lanes are emerging as a solution to address the underutilization of High Occupancy Vehicle (HOV) lanes and also means of generating revenue for state department of transportation. This paper proposes a method for dynamically determining the HOT toll price in response to the changes in traffic condition and documents procedures for estimating parameters needed for the proposed pricing strategies: revenue maximization and delay minimization. The proposed strategies have been applied to 14-miles of freeway segment in the San Francisco Bay Area, and the findings...