Citation

Reed MP, Ebert SM, Jones MLH, Park BD. U.S. National Highway Traffic Safety Administration. Washington, D.C.: U.S. National Highway Traffic Safety Administration, 2021.

Affiliation

University of Michigan Transportation Research Institute

Copyright

(Copyright 2021, U.S. National Highway Traffic Safety Administration)

The full document is available online.

Abstract

A test-track study assessed effects of initial posture and position on head motions of front -seat passengers in abrupt vehicle maneuvers. A 12 -participant pilot study in a sedan, a minivan, and a pickup truck assess ed whether head excursions differed across vehicles . With each experiencing two abrupt braking events, two lane changes, and turn -and -brake maneuvers. Head position was tracked and h ead center of gravity was estimated from landmarks on a three -dimensional scan of each participant’s head and face. Forward head excursion was slightly smaller in the passenger car than in the other two vehicles. No explanation for this finding was apparent; the vehicle kinematics were similar. A larger study with 90 participants was then conducted using a passenger seda n a nd an SUV with a range of age and body size assigned to blocks of initial conditions. F actors investigated wer e s eat position, foot placement, seat back recline angle, retractor locking, vehicle differences, and effects of leani ng i nboard on the console armrest or leaning forward while reaching. All 90 experienced two braking events, a right - going lane change, a left-going lane change, and a turn -and -brake maneuver. The two vehicles and the acceleration profiles were similar to both the pilot study and a 2018 study. A functional regression analysis of head CG trajectories on the primary axes of motion provided insight into effects of test and occupant variables on head motion. Parametric corridors were developed that can be u sed to tune and validate computational models of occupant responses in pre-crash maneuvers. Overall, the results suggest that a range of occupant head locations can be produced by abrupt vehicle maneuvers.