The following is some of the information needed to determine fault in a rollover of a tractor trailer. Generally this information is determined and presented ot teh court by an accident reconstruction expert, generally an engineer. Nonetheless a lawyer must be familiar with teh following in order to understand where the other sides expert is "cooking the books." If your lawyer is not familiar with the following, consider hiring a lawyer with more experience:
Center of mass formula. The formula to determine the center of mass location is: the total moments ÷ the total weight = the center of mass.
Datum used for accident reconstruction measurements (a datum is an imaginary plane from which all measurements are taken), arm (the distance that a weight is located from the datum), moment (the product of weight x its lever arm).
Track width – Measured to the center of the tire, or to the center of the dual wheels.
Rollover threshold – a ratio of vehicle center of mass-to-track width. This predicts at what lateral acceleration the vehicle or component will roll over.
Rollover threshold formula – the rollover threshold formula is: rollover threshold = track width ÷ height of the center of mass. RT = 1/2 TW/CM
If the rollover threshold exceeds the coefficient of friction of the road surface, there will be a spin out instead of a rollover. If the rollover threshold is larger than the coefficient of friction, and the vehicle rolled over, there is a mistake somewhere in your calculations or measurements. Therefore, if the coefficient of friction of the road surface is .40, and the rollover threshold is .46, the vehicle should spin out.
Rollover velocity formula – the rollover velocity formula is: rollover velocity = √ radius of the curve x gravity x rollover threshold. As the combined center of mass displaces laterally, it is no longer perpendicular to the track width. The effective track width (TW1) should be determined by measuring the distance from the center of the dual wheels to a point perpendicular to the shifted location of the combined center of mass. This is done by subtracting x from TW. To see how much this would change the original result, subtract x from the track width and recalculate the velocity formula. By allowing for center of mass displacement, the speed is lowered by 5 miles per hour. Therefore, suspension displacement has to be accounted for in reconstructions.