Experimental Examination of Selected Maneuvers That May Induce On-Road, Untripped Light Vehicle Rollover Phase 1-A of NHTSA\u2019s 1997\u20131998 Vehicle Rollover Research Program

009259212001Final May 1997 - July 2000PDFTech ReportNHTSA/NRD-22HS 809 357Rollover crashesStatic stabilityBrakingSliding frictionVelocityLateral accelerationAccident reductionData collectionDynamic testsLight duty vehiclesManeuver objectivityManeuver repeatabilityManeuverabilityResearch projectsUntripped rollover propensityTilt table ratioRollover accidentsRollover testsSteeringVehicle controlVehicle performanceUnited StatesNational Highway Traffic Safety AdministrationHeydinger, Gary J.Lloyd, JeffGarrott, W. RileyHowe, J. GavinForkenbrock, GarrickUnited States. Department of Transportation. National Highway Traffic Safety Administration. Vehicle Research and Test CenterNational Highway Traffic Safety AdministrationUS Transportation CollectionRollovers are the second most dangerous type of crash occurring on our nation\u2019s highways. During the five years 1991 through 1998, Fatality Analysis Reporting System (FARS) data showed that an average of 9,237 people were fatally injured each year in light vehicle rollover crashes (all types, including multi-vehicle crashes and ones for which rollover was not the first harmful event). Due to the relatively low percentage of rollover crashes, when measured by either fatalities or incapacitating injuries per occupant involved, rollover crashes are the most dangerous type of collision for all classes of light vehicles. This report documents the results of Phase I-A testing for NHTSA\u2019s 1997-1998 Light Vehicle Rollover Research program. This phase was an initial, exploratory study of using test track maneuvers to quantify on-road, untripped rollover propensity. This study examined a broad range of maneuvers that might induce on-road, untripped rollover including: J-Turn, J-Turn With Pulse Braking, Brake and Steer, Steering Reversal, Toyota Fishhook, Double Lane Change, Split-Mu Two Wheels Off-Road Recovery Simulation, and Toyota Fishhook with Pulse Braking. Three vehicles were selected for the Phase I-A testing. The vehicles selected were a 1984 Ford Bronco II, a 1997 Jeep Cherokee, and a 1990 Toyota 4Runner. These test vehicles were not in new condition. None of the test vehicles necessarily performed as would new vehicles without outriggers. However, this was not important for the Phase I-A research. The goal of the Phase I-A research was maneuver selection and test procedure development, not vehicle characterization. After the analysis was complete, it was decided that the following maneuvers should be evaluated further as part of NHTSA\u2019s rollover research: J-Turn, J-Turn With Pulse Braking, Toyota Fishhook, and Toyota Fishhook with Pulse Braking. The Brake and Steer maneuver did not produce two-wheel lift for the vehicles. The Steering Reversal procedure has many potential steering profiles and was replaced by the steering reversal profile specified in the Toyota Fishhook procedure. The Double Lane Change and Split-Mu Two Wheels Off-Road Recovery Simulation maneuvers had the potential for greater driver variability, had steering reversal type inputs found in more repeatable maneuvers, and produced two-wheel lifts less frequently than did the Toyota Fishhook maneuver.80