The Statics Stability Factor (SSF) is how the National Highway Traffic Safety Administration determines a vehicle’s rollover probability; it is the vehicle’s at-rest calculation of its rollover resistance. The number is based on the vehicle’s geometric properties. SSF is a measure of how top-heavy a vehicle is.
The location of the center of gravity is measured in a laboratory to determine the height above the ground of the vehicle’s mass. The lower the SSF number, the more likely the vehicle is to roll over in a single-vehicle crash.
A higher SSF value equates to a more stable, less top-heavy vehicle. SSF values across all vehicle types can range from around 1.00 to 1.50. Most passenger cars have values in the 1.30 – 1.50 range. Higher-riding SUVs, pick-up trucks, and vans usually have values in the 1.00 – 1.30 range. We use Police Package Crown Vic in our training programs. The SSF of the Crown Vic is 1.51, and at times we are training in SUVs such as the Ford Expedition, which has an SSF of 1.16. Needless to say, we have to approach training in these two vehicles differently.
You will have to do some digging on the sites, but before purchasing an SUV, look for the SSF number at http://www.safercar.gov