Evaluating safety at Oregon‘s isolated, high-speed, signalized intersections

Graduation date: 2010Isolated approaches at signalized intersections with posted speed limits of 45 mph or greater generally experience large numbers of rear-end and angle collisions. A combination of less attentive drivers, high operating speeds, and less than ideal intersection characteristics can result in crash frequencies well above expected rates. A number of treatment options are available to target specific safety concerns at intersections, but it can be difficult or time-consuming to determine when an intersection is experiencing abnormal crash trends. The Oregon Department of Transportation (ODOT) does not currently have a system in place for evaluating safety at isolated, high-speed, signalized intersections (IHSSIs). This thesis describes the development of a method for efficiently evaluating safety and determining potential treatment options for IHSSIs. Specifically, this method identifies data collection requirements, determines expected crash frequencies based on intersection configuration, and provides a list of safety treatment options. This information is packaged into a safety evaluation template to allow for efficient and effective IHSSI evaluations