I ride a Pride Sundancer personal mobility scooter and I am very glad to be able to report that a visit to Hoover Dam is a true pleasure for the special-needs traveler. I had been to the dam many times pre-scooter, but this last trip, 12/27/01, was my first time with wheels. If you park in the parking garage or in one of the outdoor lots within a quarter-mile of the dam, you can ride away from your car or van and onto the walkways very easily. The elevator down to the Visitors' Center entrance is easy to find, clearly marked and near the parking garage; it is also large enough to wheel in and out of easily and hold a some family members at the same time. It's even large enough to hold two wheelchairs at once, as long as both people don't mind manuvering out of the center once in.
1. If your wheelchair/scooter is too heavy for a companion to carry down a long set of stairs, and/or you cannot descend stairs, do not park in any lot more than 1/4 mile away from the dam. You will not be able to leave these parking lots. There are plenty of blue spaces in the parking garage, so don't worry.
2. If you are only partially mobile on your feet, do not make the mistake (as I did) of visiting a restroom on the dam itself; go to one in the Visitors' Center. The restroom doors on the dam lead to two short flights of stairs that end in three stalls--for the women's room, anyway--and maybe a line. Because I am partially mobile I went up the stairs and then I was stuck with no place to sit while waiting for a stall. I won't do that again and hope that if the little things add up for you during the day that you won't either.
All in all, Hoover Dam is a wonderful place to see on wheels. As I said to my father, "It's easy to tell that this is a government structure."