Deterring Unauthorized Use of Handicapped Spaces


Parking spaces designated for people with physical disabilities symbolize society’s attempts to make communities accessible.

Purpose and Anticipated Benefits

Because studies have shown that drivers without disabilities illegally park in accessible spaces and ignore handicapped-only signage, this study evaluated the difference between traditional signage and signs that explicitly stated the consequences of parking without a handicapped permit. The study goal was to show that consequence warning may improve sign effectiveness.


Michael Jones, Research and Training Center on Independent Living (RTC/IL) at the University of Kansas, and Ray Petty, a legislative liaison with the Kansas Advisory Committee for Employment of the Handicapped, conducted this survey with the advisement of Mark Mathews, Tom Seekins, Steve Fawcett, all RTC/IL staff.




The study took place in a Midwestern university town of 60,000 in which several months before the study began, a city parking ordinance authorized fines up to $250 for parking without a permit in a handicapped parking space. The study setting was two large grocery store parking lots; each had more than 200 parking spaces, four of which were designated for handicapped parking. One space, adjacent to the handicapped parking spaces, was used as a control space to measure the level of parking lot use. At store 1, metal post signs faced each pair of spaces, designating them as handicapped parking spaces. The spaces had no ground markings. At store 2, two upright metal signs were mounted on an exterior store wall in front of the handicapped parking spaces. In addition, these spaces were marked with yellow wheelchair ground signs.

Two types of handicapped parking signs were used. The standard signs had a blue background and white border with the words “Handicapped Parking” displayed in white lettering, and a white international access symbol centered in the middle of each standard sign. The metal warning signs had a white background and a black border with red lettering saying: “WARNING” with black lettering of: “Fine of Up to $250 for Parking Without Permit.” A white international access symbol was below on blue background.

Researchers watched usage in one-hour observation sessions between 4 p.m. and 6:30 p.m. while parked near the handicapped parking spaces. At the end of each one-minute interval, the researcher scored whether any of the four handicapped parking spaces were occupied and whether the vehicle displayed a state-issued handicapped license plate or a handicapped parking permit hung on the rear view mirror. A second observer did the same.

A multiple baseline design was used to analyze the effects of the two different signs on handicapped parking violations. Eleven follow-up sessions were done nine months after the observation period.


At store 1, violations decreased from 18.0 minutes per hour to 3.2 minutes during the warning sign condition. When the standard sign condition was put in place, violations increased to 20.3 minutes and then 13.0 minutes during the final warning sign condition. In follow-up observations, violations were seen an average of 3.6 minutes.

At store 2, violation went from 11.9 minutes during the first standard sign condition to 8.6 minutes during the warning sign conditions. During the reversal, violation increased to 21.2 minutes and decreased to 6.5 minutes. Parking on control space remained about the same throughout the study.


Handicapped parking signage is needed to designate parking spaces but isn’t sufficient to safeguard these spaces for their intended users. By making the consequences more apparent, signage may be more effective.


A combination of strategies such as police enforcement used along with signage may protect these spaces. Some communities have trained citizens with disabilities to monitor handicapped parking violators. Groups, too, have placed reminders on windshields of drivers not authorized to use handicapped spaces.


White, G.W., Jones, M.L., Ulicny, G.R., Powell, L.K., & Mathews, R.M. (1987). Deterring unauthorized use of handicapped parking spaces. Rehabilitation Psychology 33(4), 207-212.

Suarez‑Balcazar, Y., & Fawcett, S. B. (1990).  Handicapped parking violations:  A plan for effective consumer action. Paraplegia News, 44(3), 34‑35.

White, G. W.  (1986, April). A simple stimulus control technique to discourage violations of handicapped parking ordinances. National Association of Rehabilitation Research and Training Centers, Kansas City, MO.

White, G. W., Jones, M. L., Ulicny, G. R., Powell, L., & Mathews, R. M. (1987, June). Effects of different signs on handicapped parking violations. National Conference for Independent Living, Washington, DC.

White, G. W., Suarez de Balcazar, Y., & Fawcett, S. B. (1987, July). Collaborative action research on the issue of handicapped parking for people with disabilities. Association of Voluntary Action Scholars, Kansas City, MO.

White, G. W., Suarez de Balcazar, Y., Fawcett, S. B., Jones, M. L., Mathews, R. M., Ulicny, G. R., & Powell, L. (1987, August). Increasing compliance with handicapped parking ordinances. American Psychological Association Meeting, New York, NY.