Mitman M.F.,Fehr and Peers Transportation Consultants |
Cooper D.,University of California at Berkeley |
Dubose B.,Fehr and Peers Transportation Consultants
Transportation Research Record | Year: 2010
For more than 30 years, pedestrian safety studies have considered pedestrian-vehicle collision patterns and pedestrian and driver behavior at marked and unmarked crosswalks at uncontrolled crossings. Recent research in this area, conducted by the University of California, Berkeley, Traffic Safety Center on behalf of the California Department of Transportation (Caltrans), was designed to fill key gaps in the literature by analyzing driver and pedestrian behavior and knowledge of right-of-way laws for marked and unmarked crosswalks. The Caltrans study, as with most previous crosswalk studies, focused on urban and suburban areas (in this case, the San Francisco, California, Bay Area), where driver and pedestrian characteristics do not change significantly from day to day. After this study came the recognition that similar research was needed in rural and recreational locations, where the population frequently changes. As such, this paper summarizes results from field observations of driver and pedestrian behavior at marked and unmarked crosswalks at uncontrolled crossings during the summer in the Tahoe Basin of California. This study, also funded by Caltrans, concludes that the behavior trends identified in the study of urban and suburban areas in the Bay Area are largely similar in a rural and recreational context. This finding is significant for Caltrans, a statewide agency that is seeking to provide a consistent crosswalk installation and treatment policy for its facilities across California. Other regional and state agencies may similarly benefit from the findings of the study.
Feldman M.,Fehr and Peers Transportation Consultants |
Manzi J.G.,San Francisco Municipal Transportation Agency |
Mitman M.F.,Fehr and Peers Transportation Consultants
Transportation Research Record | Year: 2010
The empirical Bayesian method, currently the industry standard for before-and-after collision analysis, was used to perform post hoc tests on the efficacy of high-visibility school (yellow, continental-style) crosswalks in the city of San Francisco, California. Statistical analysis compared the number of collisions predicted for the after period had the enhanced crosswalks not been installed with the number of collisions observed. The analysis used data for 54 treated intersections with high-visibility crosswalks and 54 control intersections, each chosen for its geographical proximity to a treated intersection. The results from this analysis suggest a statistically significant reduction in the numbers of collisions at the intersections with high-visibility crosswalks. The estimated reduction is 37%, with the 95% confidence interval ranging from 13% to 60%. Potential limitations of this analysis, including a constant traffic volume input over time and a background reduction in collisions citywide, are discussed. In addition to the safety benefit attributable to high-visibility crosswalk markings, high-visibility crosswalks likely contribute to a sense of pedestrian comfort and overall design amenity. Future studies would enhance these results by evaluating other factors that may affect pedestrian safety at school crosswalks, such as changes in driver or pedestrian behavior and increased awareness of crosswalks and pedestrian activity.
Schneider R.,University of California at Berkeley |
Henry T.,Fehr and Peers Transportation Consultants |
Mitman M.,Fehr and Peers Transportation Consultants |
Stonehill L.,San Francisco Municipal Transportation Agency |
Koehler J.,San Francisco County Transportation Authority
Transportation Research Record | Year: 2012
The process of modeling pedestrian volume in San Francisco, California, refined the methodology used to develop previous intersection-based models and incorporated variables that were tailored to estimate walking activity in the local urban context. The methodology included two main steps. First, manual and automated pedestrian counts were taken at a sample of 50 study intersections with a variety of characteristics. A series of factor adjustments was applied to produce an estimate of annual pedestrian crossings at each intersection. Second, log-linear regression modeling was used to identify statistically significant relationships between the estimate of annual pedestrian volume and land use, transportation system, local environment, and socioeconomic characteristics near each intersection. Twelve alternative models were considered, and the preferred model had a good overall fit (adjusted R 2=.804). As identified in other communities, pedestrian volumes were positively associated with the number of households and the number of jobs near each intersection. This San Francisco model also found significantly higher pedestrian volumes at intersections (a) in high-activity zones with metered on-street parking, (b) in areas with fewer hills, (c) near university campuses, and (d) under the control of traffic signals. Because the model was based on a relatively small sample of intersections, the number of significant factors was limited to six. Results are being used by public agencies in San Francisco to understand the risks of pedestrian crossings better and to inform citywide pedestrian safety policy and investment.
Lee R.,Fehr and Peers Transportation Consultants |
Rees R.,Fehr and Peers Transportation Consultants |
Watten M.,Fehr and Peers Transportation Consultants
ITE Journal (Institute of Transportation Engineers) | Year: 2010
San Diego Association of Governments (SANDAG) has recently released smart growth design guidelines, Designing for Smart Growth, Creating Great Places in the San Diego Region (June 2009) that propose parking policies and design recommendations specifically for smart growth development. Residential units in smart growth developments generally belong to Parking Generation's multi-family residential category. Parking Generation states that the average vehicles owned per household is between 1.0 and 1.3 for areas within one-third mile of a light rail station and more than 10 miles from the central business district. The lowest office parking supply requirement found in the San Diego region was 3.33 spaces per 1,000 square feet, substantially higher than the Parking Generation average rate. Shared Parking recommends a parking supply of between 3.6 and 4.5 parking spaces per 1,000 square feet of retail uses to meet peak parking demand. Current San Diego parking requirements show a range of 3.3 to 5 spaces per 1,000 square feet, with an average of around 4.