Kinetic energy of vehicle where m=mass and v=velocity is ½mv².
If 0.56 is µ, the coefficient of friction, the frictional force is µmg=17.92m where g=32ft/s².
The work done by friction=537.6m acting over 30 feet.
This counterbalances the KE of the vehicle so 537.6m=½mv². So v²=1075.2 and v=32.79fps=22.36mph approx. (36kph).