Using Complementary Intersection and Segment Analyses to Identify Crash Hot Spots

Transportation agencies commonly identify and mitigate crash hot spots. Using a full roadway (i.e., including both intersections and segments) crash analysis is beneficial, but the results may be skewed towards locations with high intersection crashes. The purpose of this paper is to demonstrate the use of a combination of two unique, yet complementary crash hot spot analyses, one for intersections and one for roadway segments. The combination of the two allow for an in-depth analysis of causes associated with specific roadway conditions to identify locations that are experiencing more injury-causing crashes than predicted. The crashes on the state route network are separated into one of the two analyses; crashes within the influence area of major intersections become part of the intersection analysis and all other crashes become part of the segment-only analysis. Due to the separation between intersection- and segment-related crashes, safety concerns can be brought to light that might otherwise go unnoticed in a full network analysis. For example, crashes related to driveways or excessive queuing found in the segment analysis indicate a potential need for access management countermeasures. In addition, locations with both adjacent segment and intersection hot spots can be pinpointed as places for more in-depth analysis of the contributing circumstances surrounding the crashes at these locations. Agencies that use an intersection analysis and a segment analysis together to identify crash hot spots can benefit from an increased accuracy of hot spot locations. Furthermore, the approach to mitigating safety concerns can become clearer if hot spots are separated into intersections and segments.