ADAGuy, respectfully, I have used the language and definitions published in the code to show that the code sections you stated do not apply. Your response is to call the the definitions in CBC 202 "semantics". What is your method of deciding when code language actually means what it says, and when it's merely "semantics"?
I agree that a wheelchair user should be able to enter the garage using their van. The question then becomes, how much vertical clearance should a garage have to serve the van? A bunch of people at ANSI got together in a committee and decided: 8'-2", then they took a break for lunch. The DOJ decided "that sounds about right", and put 8'-2" in ADA. Once upon a time UFAS said 114", then they said "never mind, let's follow ADA and make it 8'-2". California also followed with 8'-2".
Again, the original post described a situation where the garage DID provide 8'-2" (98") vertical clearance at the entrance.
Thus it already complies with 11B-502.5 which says, "Parking spaces, access aisles and vehicular routes serving them shall provide a vertical clearance of 98 inches (2489 mm) minimum."
The remainder of the original post was wondering whether a vehicle that was built to be 8'-2" tall could successfully pass underneath an 8'-2" tall headroom if drive aisle had an approach slope. But this is irrelevant, because
the code does not prescribe the measurement of vehicle height, it prescribes the vertical clearance of the building at any point along the path. Vertical clearance = measured vertically.
The is analogous to wondering whether a 6'-8" tall person would bump their head when ascending/descending a stairway that already has the code-compliant 6'-8" vertical clearance. The answer is: the biometrics and gait of an occupant is irrelevant to the process of plan checking for prescriptive code compliance. You measure the building, not the person. If you as a designer are concerned about this issue, you are free to provide greater vertical clearance than code minimum if you want. Instead, the code committees decided to make a prescriptive requirement that is quickly and easily applied and checked: you measure vertically at every point along the vehicle path for 8'-2" vertical clearance. No need to check for anything else.
Vehicles are unique designs, with varying lengths, varying suspension, varying wheel sizes. Some are customized with lift kits. Some may ride lower when they have a full GVW vs riding empty. They may ride lower on a colder day, when the tire pressure is lower. Some may have bad shocks and bounce while they ride, with a constantly changing height.
Most relevant to what the original poster said, driving on an "approach angle" slope will result in varying vertical heights of the vehicle depending on the wheelbase of the vehicle, the degree of the grade break, and the grade break horizontal location relative to the garage entrance, and the location of the highest point of the car relative to these other points. It will be different for every vehicle.
The code does NOT say "Parking spaces, access aisles and vehicular routes serving them shall provide sufficient clearance for any vehicle that is up to 98 inches in height." A plan checker would have possess all knowledge about the wheelbase, and body shape relative to the wheelbase, of all possible vehicles that would ever enter the garage.
Likewise, an accessible parking stall is prescribed in 502.2 as 9' wide and 18' long. Nothing in 502.2 describes the required back-out space in the adjacent drive aisle; that varies depending on local planning codes.
- Question: "What if the vehicle is really wide and has a lousy turning radius so that it can't make it into the stall? Or what if the van is longer than 18 feet?"
- Answer: we are not measuring or designing the vehicle. We are measuring the stall, and the stall size was decided by code committees.
