The building seeking LEED certification is a downtown, high-rise building without feasible street parking. The building has an attached parking structure. Any building employee driving a car would park in the parking structure. Employees use electronic cards (with identifying information including name and kind of car) to enter and exit the parking structure. Daily parking activity is monitored. May I use parking structure data rather than a survey (I would assume that any building occupant who didn't park in the parking structure arrived by an alternative mode)? Thanks for your time.