http://www.rssboard.org/rss-specification 720 https://escholarship.org/uc/its_tsc_cp/rss Recent eScholarship items from Conference Papers Tue, 23 Jun 2026 10:21:10 +0000 https://escholarship.org/uc/item/7vk8n6s4 The objective of this work is to identify better metrics of exposure when comparing traffic crash risk across modes or across locations. We propose that total time travelled should be used for road user exposure to crash risk. The idea behind this is that travel time reflects the differences in speeds across different modes and hence should be used as the basic exposure metric from which crash risk based on other metrics, such as travel distance, can easily be derived. We also propose that when comparing crash risk of different modes across different locations the time-based mode share should be used as an explanatory variable. By using mode share we are generalizing the safety in numbers concept which focuses on absolute numbers. This work presents a discussion on why these two metrics were chosen and how they are different from the commonly used metrics. Quantitative evidence for the choice of time-based metrics is also presented using travel survey data to compare crash risk... https://escholarship.org/uc/item/7vk8n6s4 Fri, 24 Apr 2026 00:00:00 +0000 Guler, S. Ilgin Grembek, Offer Ragland, David R https://escholarship.org/uc/item/92r8f3xr This paper presents a method to assess the safety of uncontrolled intersections considering both conflict probability and severity, which are two major properties of traffic conflicts. This method provides not only the safety level of the entire intersection but also the distribution of safety within intersections. Intersections are modelled by a two-dimensional Cartesian coordinate system and the internal space of intersections is divided into cells. Firstly, vehicle movement characteristics of at uncontrolled intersections are modelled. Secondly, conflict probability of each cell within the intersection is estimated considering approaching probability and lateral migration probability of vehicles. The quantification of conflict severity is based on kinetic energy loss of potential crashes. Grey cluster analysis is used to combine conflict probability and severity to model the safety assessment of each cell. Thirdly, the application of this method discussed, and an overall safety... https://escholarship.org/uc/item/92r8f3xr Wed, 22 Apr 2026 00:00:00 +0000 Ma, Yingying Qin, Xiaoran Grembek, Offer Chan, Zhiwei https://escholarship.org/uc/item/05w6f3q6 Rear-end collisions would occur if vehicle speeds decrease abruptly when encountering kinematic waves (KWs) emanating from active bottlenecks. This study aims to develop a control strategy in variable speed limits (VSL) to reduce rear-end collision risks near recurrent bottlenecks. Using the crash prediction model developed for rear-end collisions related to risky KWs, the effectiveness of VSL control strategies were evaluated in the cell transmission model (CTM). Several strategies were tested in sequence to determine the best case for risk reduction. Results of this study show that the collision risk can be effectively reduced if the speed limit is lowered in an opportune occasion. The VSL needs to response quickly to the fast changing traffic condition while should simultaneously avoid the potential disturbance to the traffic. According to the simulation results, the following recommendations are made when implementing the VSL to improve safety situation near recurrent bottlenecks:... https://escholarship.org/uc/item/05w6f3q6 Wed, 22 Apr 2026 00:00:00 +0000 Li, Zhibin Liu, Pan Bigham, John M.. Ragland, David R.