Lindsay S. Arnold

Pilot Model for Estimating Pedestrian Intersection Crossing Volumes

Better data on pedestrian volumes are needed to improve the safety, comfort, and convenience of pedestrian movement. This data collection requires more carefully developed methodologies for counting pedestrians as well as improved methods of modeling pedestrian volumes. The methodology used to create a simple pilot model of pedestrian intersection crossing volumes in Alameda County, California, is described. 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 characteristics. Three alternative model structures were considered, and the final recommended model has a good overall fit (adjusted R2 = .897). Statistically significant factors in the model include the total population within a 0.5-mi radius, number of jobs within a 0.25-mi radius, number of commercial retail properties within a 0.25-mi radius, and the presence of a regional transit station within a 0.1-mi radius of an intersection. The model has a simple structure, and it can be implemented by practitioners using geographic information systems and a basic spreadsheet program. Because the study is based on a relatively small number of intersections in one urban area, additional research is needed to refine the model and determine its applicability in other areas.

Methodology for Counting Pedestrians at Intersections: Use of Automated Counters to Extrapolate Weekly Volumes from Short Manual Counts

Accurate methods of counting pedestrians are needed to quantify exposure for safety analysis, rank infrastructure improvements and safety programs by priority, evaluate the benefits of pedestrian projects, develop models of pedestrian volumes, and track changes in pedestrian activity over time. However, pedestrian counts are still much less common than motor vehicle counts in most communities. In addition, existing count methodologies are not standardized and rarely provide enough information to extrapolate to weekly, monthly, or annual volumes. This exploratory study presents a methodology for estimating weekly pedestrian intersection crossing volumes based on 2-h manual counts. The methodology, implemented in Alameda County, California, involves a combination of manual and automated counts to determine weekly volumes. More than 690,000 pedestrians were counted during the 13-week study period. Manual counts were conducted at a set of 50 intersections. Automated counts from sidewalk locations in close proximity to a subset of 11 intersections were used to adjust these counts for time of day and week, surrounding land use characteristics, and weather conditions. The extrapolated pedestrian volume estimates were then used to calculate the number of reported crashes per 10 million pedestrian crossings at each of the study intersections. The results of this study demonstrate how pedestrian volumes can be routinely integrated into transportation safety and planning projects.

Association Between Roadway Intersection Characteristics and Pedestrian Crash Risk in Alameda County, California

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 (the number of crashes per 10,000,000 pedestrian crossings) with intersection characteristics. In addition, more than 30 variables were considered for use in the development of a statistical model of the number of pedestrian crashes reported at each study intersection from 1998 to 2007. After the pedestrian and motor vehicle volumes at each intersection were accounted for, negative binomial regression showed that significantly more pedestrian crashes occurred at intersections with more right-turn-only lanes, more nonresidential driveways within 50 ft (15 m), more commercial properties within 0.1 mi (161 m), and a greater percentage of residents within 0.25 mi (402 m) who were younger than age 18 years. Raised medians on both intersecting streets were associated with lower numbers of pedestrian crashes. These results, viewed in combination with other research findings, can be used by practitioners to design safer intersections for pedestrians. This exploratory study also provides a methodological framework for future pedestrian safety studies.

Factors Associated with Hit-and-Run Pedestrian Fatalities and Driver Identification

As hit-and-run crashes account for a significant proportion of pedestrian fatalities, a better understanding of these crash types will assist efforts to reduce these fatalities. Of the more than 48,000 pedestrian deaths that were recorded in the United States between 1998 and 2007, 18.1% of them were caused by hit-and-run drivers. Using national data on single pedestrian-motor vehicle fatal crashes (1998-2007), logistic regression analyses were conducted to identify factors related to hit-and-run and to identify factors related to the identification of the hit-and-run driver. Results indicate an increased risk of hit-and-run in the early morning, poor light conditions, and on the weekend. There may also be an association between the type of victim and the likelihood of the driver leaving and being identified. Results also indicate that certain driver characteristics, behavior, and driving history are associated with hit-and-run. Alcohol use and invalid license were among the leading driver factor associated with an increased risk of hit-and-run. Prevention efforts that address such issues could substantially reduce pedestrian fatalities as a result of hit-and-run. However, more information about this driver population may be necessary.

Pedestrian Counting Methods at Intersections: A Comparative Study

Resources for implementing countermeasures to reduce pedestrian collisions in urban centers are usually allocated on the basis of need, which is determined by risk studies. Risk studies commonly rely on the determination of pedestrian volumes at intersections. The methods used to estimate pedestrian volumes include direct counts and surveys, but few studies have addressed the accuracy of these methods. This paper investigates the accuracy of three common counting methods: manual counts with sheets, manual counts with clickers, and manual counts with video cameras. The counts took place in San Francisco, California. For the analysis, the counts obtained with video images were assumed to represent the actual pedestrian volumes. The video recordings were made at the same time as the clicker and sheet counts. The results indicate that manual counts with either sheets or clickers systematically underestimated pedestrian volumes. The error rates ranged from 8% to 25%. Additionally, the error rates were greater at the beginning and at the end of the observation period, possibly because of the observers lack of familiarity with the tasks or fatigue.