- A rollover is defined as any vehicle rotation of 90° or more about any true longitudinal or lateral axis.
Rollover Occurrence Conditions
- Traveling at high speed on curved road.
- Sever cornering maneuver.
- Traveling on collapsing road and suddenly providing steering input for a vehicle with a low level of roll stability.
- Losing control due to a rapid decrease of friction, such as driving on icy road.
- Laterally sliding of the road.
- Sliding from a cliff.
Factors affect the vehicle to rollover
- These factors are tire and vehicle characteristics, environmental conditions, and drivers.
- Rollover can happen on a flat road, on a cross-slope road, or off road.
- Rollover can be divided into two categories: tripped rollover, and untripped rollover.
- Tripped rollover is caused by a vehicle hitting an obstacle.
- Traveling at high speed on a curved road: When a vehicle travels on a curved road, lateral centrifugal force will pull it in an outboard motion.
- Traveling on a collapsing road and suddenly providing steering input for a vehicle with a low level of roll cause a yaw disturbance.
- Losing control due to a rapid decrease of friction, such as driving on an icy road:
"Steering can cause yaw motion because forces on the tires in the lateral direction are strong enough to roll the vehicle."
Vehicle and non vehicle factors of rollover
- The study of vehicle rollover is a complicated topic.
- The phenomenon of rollover is difficult to predict.
- Rollover involves many vehicle factors and some non vehicle factors, such as the road friction coefficient, obstacles on the road, the type of road shoulder, road and shoulder inclination angles, driver steering patterns, and others.
- To simplify the complicated overall analysis, a steady-state rigid model and a steady-state suspended model are most commonly used.
- Some simple metrics have been developed to evaluate the static and dynamic stability of vehicles, such as the
- static stability factor (SSF),
- the tilt table ratio (TTR),
- the critical sliding velocity,
- the dynamic stability index,
- the static stability factor and the tilt table ratio