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Factors that Influenced Drivers’ Responses to a Slower-Moving, or Slowing Lead Vehicle
ISSN: 0148-7191, e-ISSN: 2688-3627
To be published on April 06, 2021 by SAE International in United States
Event: SAE WCX Digital Summit
The most common fatal rear end crash in 2014 through 2018 involved a stopped or slow-moving lead vehicle being struck by a vehicle traveling 50 to 70 mph. These crashes have been referred to as looming-related events. Looming relates to the rate of increase of the visual subtended angle of the lead vehicle, or in simple terms, how fast the lead vehicle appeared to grow as the approach driver got closer. Looming is one of many cues that are available to drivers. This research will address other cues that are available to drivers, and then determine which of those cues were associated with a change in driver response among naturalistic drivers in the Second Strategic Highway Research Program (SHRP-2). While there might be cues other than looming available to drivers, very few were associated with changes in drivers’ responses. For instance, when the lead vehicle was under an overpass, near trees, or signs, response to the lead vehicles were similar to when those objects were not present. However, in congested traffic, and in the presence of a yellow or red traffic signal, drivers responded much earlier to the lead vehicle. Overall, drivers applied the brakes when the looming threshold equaled approximately 0.035 radians per second. When the lead vehicle was stopped, much fewer than half of drivers applied the brake when more than 1.3 second from impact. Also, not all lead vehicle response time events were similar. When the lead vehicle was decelerating, it led to several near crashes, but rarely a crash. However, when the LV was stopped, the probability of a crash increased significantly.
- Jeffrey Muttart - Crash Safety Research Center, LLC
- Michael Kuzel - 4M Consulting Group, LLC
- Swaroop Dinakar - Crash Safety Research Center, LLC
- Suntasy Gernhard - Macha - Crash Safety Research Center, LLC
- Darlene E. Edewaard - Crash Safety Research Center, LLC
- Stephanie Appow - Crash Safety Research Center, LLC
- Connor Dickson - Crash Safety Research Center, LLC