Jason F Kennedy

Pedestrian and Bicyclist Exposure to Risk: Methodology for Estimation in an Urban Environment

There is currently no commonly accepted or adopted measure of pedestrian and bicycle exposure to risk. Consequently, a large portion of the field of pedestrian and bicycle safety is lacking an adequate means to evaluate the effectiveness of its efforts. The current study presents a proposed metric for measuring pedestrian and bicycle exposure to risk: hundred million pedestrian or bicycle miles of roadway (or other motor vehicle shared facility) traveled. A method for implementing the proposed exposure metric is described for eight shared-facility types characteristic of the urban environment of Washington, D.C. These facilities include three types of intersections, midblock road segments, driveways, alleys, parking lots, parking garages, school areas, and areas with playing, dashing, and working in the roadway. The methodology is then used to calculate the annual pedestrian and bicycle exposure for the city for the calendar year 2007. The results of these calculations revealed 0.82 hundred million miles for pedestrian exposure and 0.37 hundred million miles for bicyclist exposure. In this way both the feasibility and scalability of the proposed metric were successfully demonstrated for a relatively large urban environment. Thus the proposed metric has the potential to eliminate one of the major obstacles in the pedestrian and bicycle safety field, the lack of adequate exposure data. Although further refinement and validation are still needed, the proposed metric provides a possible initial foundation to develop a national unit of risk exposure for pedestrians and bicyclists.

Segway Rider Behavior: Speed and Clearance Distance in Passing Sidewalk Objects

The Segway Human Transporter is becoming more prevalent on urban sidewalks. This experiment investigated the approach speed and passing clearance that Segway devices exhibit on encountering a variety of obstacles on the sidewalk. The experiment was conducted with a sample of 20 Segway operators: 10 experienced operators and 10 novices. For the given experimental course and procedures, the results of the study revealed that (a) Segway riders approach obstacles at a mean speed of about 4.5 mph (7.2 km/h) with a range from 2.7 mph (4.3 km/h) to 6.8 mph (10.9 km/h); (b) Segway riders pass obstacles with a mean clearance of about 14.5 in. (36.7 cm) with a range from 3.3 in. (8.4 cm) to 43.2 in. (110 cm); (c) Segway riders pass moving pedestrians at an average speed of about 5 mph (8.1 km/h) and with an average clearance of 35.9 in. (91.2 cm); (d) Segway riders pass obstacles more slowly by about 0.5 mph (0.8 km/h) on average and closer by about 17.6 in. (44.7 cm) on average on a narrow as opposed to a wide sidewalk; and (e) experienced Segway riders pass faster by about 1.9 mph (3.1 km/h) on average than do novice riders. In the current experiment, the average passing event involving a Segway rider and a pedestrian required a minimum total distance of approximately 7.0 ft (2.1 m). These data should assist engineers in calculating the impact of various mixes of Segway traffic on sidewalks.

Test and Evaluation of Systems to Warn Pedestrians of Turning Buses

As part of a cooperative agreement with FTA, the Tri-County Metropolitan Transportation District of Oregon (TriMet) in Portland, Oregon, conducted a demonstration test of three commercially available systems to warn pedestrians of turning transit buses. Forty-five buses were equipped with the warning systems for turning (15 buses with each of the three systems) for 7 months (between March and September 2014). A robust evaluation of the systems, including surveys and focus groups with bus operators and the general public, a video-based analysis of pedestrian behaviors, interviews with TriMet personnel, and a benefit– cost analysis, was conducted. The results showed a range of perceptions, levels of acceptance, and recommendations for improving the technologies. The benefit–cost results showed positive benefit–cost ratios even under the most conservative assumptions about the benefits and costs associated with the turn warning systems.