Wheelchair and scooter ramps are portable or permanent and can be used either in your car or van or your home.
For permanent ramps, you need a length which is 1 foot of ramp for every inch of height. If your steps measure 8 inches high, you need an 8 foot long ramp.
For portable ramps (temporary) you need a length which is 6 inches of ramp for every inch of height. If your height of steps is 8 inches high, you need a 4 foot long ramp.
Side doors of vans typically need a 7 foot long ramp. Backs of vans need 7 or 8 foot long ramps. Watch the bumper on the back. Some vans need an extended plate to clear the bumper on the back.