Comparison of Time-Proximity and Evasive Action Conflict Measures: Case Studies from Five Cities

Abstract

Interest has grown in using traffic conflicts for studying safety from a broader perspective than relying only on collision data. Traffic conflict analysis is typically performed through the calculation of traditional conflict severity measures such as time-to-collision and postencroachment time. These measures rely on road users getting within specific temporal and spatial proximity from each other and therefore assume that proximity is the surrogate for severity. However, this assumption may not be valid in some driving environments where close interactions between road users are common and sudden evasive actions are frequently used to avoid collisions. It is suggested that evasive action–based conflict indicators can assess the analysis in some less-organized traffic environments. This study focused on the severity evaluation of pedestrian conflicts. Pedestrian evasive actions were reflected mainly in variations of spatiotemporal gait parameters (step frequency and step length). The objective was to compare the use of time proximity and evasive action–based conflict indicators in evaluating the severity of pedestrian conflicts in different traffic environments. Video data from intersections in five major cities—Shanghai, China; New Delhi, India; New York City; Doha, Qatar; and Vancouver, British Columbia, Canada—were analyzed with automated computer vision techniques to extract pedestrian-involved conflicts and calculate conflict indicators. Results show that evasive action–based indicators were more effective in identifying and measuring the severity of pedestrian conflicts than time proximity measures in traffic environments such as Shanghai and New Delhi. However, evasive action measures did not show the same potential in Vancouver and Doha, where time proximity measures were more effective.

Assessing Sidewalk and Corridor Walkability in Developing Countries

“…A third important implication of the study involves its inclusion of driver behavior. Previous research in developing countries has indicated that drivers leave most of the responsibility of avoiding accidents to pedestrians, even in residential areas [18,49,62]. Accordingly, the proposed method suggests that driver behavior is a key factor that needs to be measured and evaluated in terms of how such behavior impacts walkability in certain neighborhoods.…”

Group Gap Acceptance: A New Method to Analyze Driver Behavior and Estimate the Critical Gap at Multilane Roundabouts

“…The critical gap for three-lane roundabouts, but the value of the overall critical gap, seems to be much lower than that obtained for one-and two-lane roundabouts [3][4][5][6][7][8]. Considering that driver behavior is a major contributor to the operational performance of roundabouts, the results may be an indication of aggressive driver behavior, which was identified in prior studies conducted in Qatar [16][17][18]. Such behavior may be caused by drivers becoming frustrated at heavily congested roundabouts and entering the roundabout when there is an insufficient gap.…”

Measuring, Mapping, and Evaluating Daytime Traffic Noise Levels at Urban Road Intersections in Doha, Qatar

“…Most of the population lives in the city of Doha. The city suffers from many problems such as traffic congestion, traffic safety, air pollution, noise pollution, and aggressive driving [43][44][45][46][47][48][49][50][51][52]. The study was conducted at eight intersections as shown in Figure 1.…”