Q: In determining a vehicle's peak roll rate, is it simply the degrees it rolls during the period of time which is degrees per second or is it much more complicated than that?
A: Peak Roll Rate is the measured rolling rate, measured in deg/sec during a rollover test.
You'll note in that the test result summary (see above) they list the peak and then the mean or average roll rate.
The mean or average roll rate is sometimes computed in 3 different ways:
- 1) by averaging the roll rate throughout the test (sampling measurements every tenth of a second and then taking an average) (deg/sec)
- 2) taking the total amount of roll and dividing by time, (deg/sec) or
- 3) taking the total roll and dividing by distance (deg/foot)
In a lot of rollovers you may observe measurements with wildly changing rolling rates (see above) as components strike the ground.
Vans you will find have rolling rates which are generally more consistent than other vehicles (a box rolls easier than a vehicle with a smaller top than the base)
When the tires hit and the tire/suspension gets possibly damaged or when the roof buckles or deforms, these all can change the roll rate rapidly.
Also variations in the local terrain can change the rolling rate during a rollover.