Study Using Historic US Crash Data Estimated 18-84 Percent Crash Avoidance for Left Turn Across Path or Opposite Direction with Automated Driving Systems (ADS).
A Total of 501 Crashes in USA were Reconstructed in Simulation to Evaluate the Effect of ADS in Left Turn Crash Avoidance.
Nationwide, United States
Crash and injury prevention estimates for intersection driver assistance systems in left turn across path/opposite direction crashes in the United States
Summary Information
Intersection Advanced Driver Assistance Systems (I-ADAS), sometimes referred to as left-turn assist, have the potential to prevent or reduce the severity of Left Turn Across Path/Opposite Direction (LTAP/OD) crashes. This study estimated the number of LTAP/OD crashes and injuries that could be prevented in the United States for the hypothetical case where involved vehicles were equipped with an I-ADAS. This study reconstructed 501 past vehicle-to-vehicle LTAP/OD crashes in the USA from the National Motor Vehicle Crash Causation Survey (NMVCCS) to evaluate 30 different I-ADAS system variations for each crash.
METHODOLOGY
In this study, variations of the I-ADAS system were simulated based on combinations of five Time-to-Collision (TTC) activation thresholds, three latency times, and two response types: automated braking and driver warnings. TTC is the time remaining before two moving objects collide, based on their current speeds and paths. Two different sightline scenarios were modeled for each crash: one where the turning vehicle was visible well before the intersection and another where it became visible only upon entering the intersection. The simulation produced three possible outcomes for I-ADAS interventions: unmodified, modified, and avoided crashes. In unmodified cases, neither vehicle had I-ADAS braking, so the outcome remained identical to the original crash record. Modified cases involved I-ADAS braking, which altered the crash characteristics but did not prevent the crash. In avoided cases, I-ADAS braking successfully prevented the crash from occurring.
FINDINGS
- This study predicted that an I-ADAS system that automatically applies emergency braking could avoid 18 to 84 percent of all LTAP/OD crashes.
- Results also indicated that an I-ADAS system that applies emergency braking could prevent 47 to 93 percent of front-row occupants from getting injured.
