These are the accessible parking failures that show up most often on final inspection, when they are also the most expensive to fix.
The most common defect by far. The space passes the tape measure and fails the smart level. Once the asphalt is down, the correction is milling and repaving. Set spot elevations on the grading plan and check them before the final lift.
An access aisle without hatched striping is treated as a parking space by every driver who sees it. The aisle has to be marked its full length, and it has to be maintained — striping is not a one-time item.
A painted symbol on the pavement alone does not satisfy the requirement, because it disappears under a parked car. The vertical sign is what makes the space enforceable.
At least one in every six accessible spaces must be van-accessible, with a wider access aisle and adequate vertical clearance along the route in and out. Small lots forget this constantly.
An access aisle that dead-ends into a curb forces a wheelchair user into the drive aisle. Every accessible space needs a curb ramp or a flush connection to the sidewalk, positioned so the ramp does not project back into the aisle.
Accessible spaces located wherever the layout had room left over, rather than on the shortest route to the entrance, fail the intent even when they pass the count.
Each of these is trivial on the plan and costly in the field. Catch them at design.