Wheelchair accessible vehicles can be accessed either by a ramp or by a lift. Each one has advantages and disadvantages that should be considered to help you decide which would be the best choice for your vehicle.
Most ramps can be extended manually, this makes them less expensive and they require less maintenance, than a lift. It does mean, however, that the wheelchair user will almost certainly require assistance to deploy them, as they can be heavy and require a certain amount of dexterity.
A rear entry wheelchair accessible vehicle with a ramp requires quite a large amount of space behind the vehicle in which to extend the ramp and for the wheelchair user to manoeuvre up it. Longer ramps are less steep and therefore easier to get up, but they require more room. A ramp should not have a slope of more than 13-degrees, and while most electric wheelchairs can make it up this grade of slope, be aware that some cannot. Winches can be installed to assist the entry of both manual and electric wheelchairs, but a winch cannot overcome the problem of an overly steep ramp.
Descending from the vehicle involves reversing down the sloping ramp, which some people can find unnerving. The edges of the ramp should be raised to guide the wheelchair down, but sometimes, standard ramps are not very wide, so if the wheelchair is large, or particularly wide, a ramp may not be suitable.
Lifts, and some ramps, are powered, and operated from a panel located within the vehicle or with a cordless hand-held control. That means that there are more things that can go wrong with them and that they need a regular maintenance routine. Lifts have the advantage of requiring less operating space, and being able to accommodate larger wheelchairs, but some people feel vulnerable and exposed on them.