Community intervention to deter illegal parking in spaces reserved for the physically disabled

Illegal use of reserved parking spaces represents a major obstacle to the independence and mobility of people with physical disabilities. Using an ABACACA reversal design, the daily rates of illegal parking in four reserved spaces were examined across three types of sign displays: (a) a vertical sign alone or in combination with (b) a message sign that announced the possibility of public surveillance or (c) a message dispenser device that announced community involvement and dispensed politely worded reminder notes. The average rate of illegal parking dropped from 51.3% during the initial vertical sign phase to 37.3% under the message sign condition, followed by an increase to 50.4% when the message was removed. Illegal parking decreased to 24.5% when the message dispensers were first used (followed by an increase to 57.0% when they were removed) and to 23.7% when the message dispenser condition was repeated. Illegal parking in the final vertical sign condition failed to return to previous levels (M = 37.3%).