Arizona is not alone in singling out toilets. Colorado, Georgia, Vermont and Virginia are among states that have also closed rest stops, though Virginia’s new governor, Robert F. McDonnell, has vowed to reopen 19 stops that closed last year.

“It’s a safety problem, not only for us but car drivers,” said Clayton Boyce, the spokesman for the American Trucking Association, which has fought rest stop closings in Virginia and elsewhere. “We think it is a pretty bad idea.”