Freeway Crash Timeline Characteristics and Uses

Abstract

Timeline information for freeway crashes was extracted using 10,589 crashes, 2,816 of which were matched with enforcement agency dispatch records and 320 of which were matched with ambulance dispatch records. The average time between when a crash occurred and when the crash scene was cleared was 52.2 min. The enforcement agency was notified 3.4 min after the crash, and the first responding officer arrived at the crash scene 6.0 min later. The ambulance dispatcher was notified 5.1 min after the first responding officer arrived at the scene, and the first ambulance arrived at the scene 7.5 min later, remained at the scene 20.9 min, and arrived at the hospital 10.9 min after it left the crash scene. Enforcement agency notification and response times were not affected by crash and environmental factors; however, enforcement agency on-scene time (representing 80 percent of crash duration) was statistically related to crash type, crash severity, need for emergency medical services transport, air bag deployment, light condition, manner of collision, road condition (presence of precipitation), number of injuries, number of involved vehicles, need for towing services, and extent of vehicle damage. The shortest crash durations were associated with two-vehicle crashes, crashes involving property damage only, and crashes involving vehicles able to drive away. The longest crash durations were those involving very severe vehicle damage, occupant medical transport, an overturned vehicle, and those occurring at night.

Operational impacts of incident quick clearance legislation: a simulation analysis

“…In most cases, if incidents could be cleared within 10 minutes of the arrival of an incident responder, drivers should be able to clear the travel lanes themselves. Other studies have shown that average time for first‐responding law enforcement officers to arrive at the scene of an incident is 9.8 minutes after the incident 23. Freeway service patrols, publicly operated vehicles actively monitoring traffic flow and aiding in incident clearance, usually average a response time of 9 minutes 24.…”

“…The low end of the range was set at 2 minutes as suggested by Dunn and Latoski 9. Based on References 23, 24, the upper limit of the range was conservatively set at 10 minutes to capture the impact of incidents removed by drivers, rather than incident response authorities. Personnel at the Greenville TMC verified that these limits were appropriate.…”

Assessing Weather, Environment, and Loop Data for Real-Time Freeway Incident Prediction

“…To account for unreported crashes, assume that the actual number of accidents is twice the reported figure; that is equivalent to 4.66 accidents per year per station. A study by Drakopoulos et al reported that the average time from a crash occurrence until it was cleared was 52.2 min(18). Therefore, it was logical to assume that each crash occurrence affects the traffic conditions for 1 h on average.…”

Incident occurrence and response on urban freeways

“…First, there is strong empirical evidence that severity outcomes are crash type-dependent (Yau, 2004;Pai and Saleh, 2008). Second, incident management (in terms of type of EU needed, overall duration, and so on) is related to crash type (Drakopoulos et al, 2001); the model outcomes could be used to estimate on a real-time basis the location of crash-specific emergency units such as fire-fighting vehicles. Third, crash type propensity (if combined with a corresponding crash frequency analysis) could be used in crash prediction modeling.…”