Technically, driving the vehicle INTO the bay is part of the inspection, you are checking the brake function and steering input (wheather or not this actually happens is quite debatable) This is why you'll usually run into an issue with being able to pull it in the bay.
having a bay large enough also limits what can be inspected due to type of vehicle. anything over I beleive 10k gross weight can also be inspected under federal Motor vehicle Inspections. (Our E350 box vans are Federal inspected, while my E350SD 5.4L gas standard cargo van is NC Emission exempt, yellow sticker)
