closing speed

A 40 foot van is traveling at 60 mph and is trailing a ramp from the
back with the cargo doors open. A car is following the van with the
intent to drive up the ramp and into the cargo bay. The car is
traveling at 65 mph as it approaches and moves on to the ramp.

My question is would the car have to decelerate from 65 mph to 0 mph
within this 40 feet or would it only need to decelerate from 5 mph?
and why?