Here's a little story for you to consider. I worked in a retail strip mall for several years. A good portion of the folks that parked in the handicapped spots were elderly and not particularly well coordinated. AT LEAST once per month we would have to straighten or replace the sign posts, because these drivers would either misjudge how far away they were and they'd hit the pole pulling into the space, or often they "didn't see" the signpost at all, and they'd plow right through it instead of backing out of the space.