This paper summarizes the results of test maneuvers devised to measure on-road, untripped, rollover propensity. Complete findings from this research are contained in [1].
Twelve test vehicles, representing a wide range of vehicle types and classes were used. Three vehicles from each of four categories: passenger cars, light trucks, vans, and sport utility vehicles, were tested.
The vehicles were tested with vehicle characterization and untripped rollover propensity maneuvers. The vehicle characterization maneuvers were designed to determine fundamental vehicle handling properties while the untripped rollover propensity maneuvers were designed to produce two-wheel lift for vehicles with relatively higher rollover propensity potential. The vehicle characterization maneuvers were Pulse Steer, Sinusoidal Sweep, Slowly Increasing Steer, and Slowly Increasing Speed. The rollover propensity maneuvers were J-Turn, J-Turn with Pulse Braking, Fishhook #1 and #2, and Resonant Steer.
The degree of two-wheel lift produced for each vehicle/maneuver/steer direction combination was given a score based on whether the lift was minor, moderate, or major. No two-wheel lift was given a zero score. The individual vehicle/maneuver/steer direction scores were combined to produce two ratings: a Steering Maneuver Score and a Pulse Braking Score. The Steering Maneuver Score was based on J-Turn, Fishhook #1, and Fishhook #2 results, while the Pulse Braking Score was based on J-Turn with Pulse Braking results.
The Steering Maneuver Scores were found to be related to the rollover stability metrics of the vehicles. The Pulse Braking Score was related more to whether the vehicle was equipped with a four-wheel antilock brake system (4WAL) or not. For those vehicles without 4WAL, the Pulse Braking score related to the rollover stability metrics.