Cope J G, Allred L J, Morsell J M
Department of Psychology, East Carolina University, Greenville, North Carolina 27858-4353.
J Appl Behav Anal. 1991 Spring;24(1):59-63. doi: 10.1901/jaba.1991.24-59.
The percentage of illegal parking in spaces reserved for the physically disabled was monitored under three sign conditions: ground markings, ground markings plus vertical signs, and vertical signs containing a message that concerned citizens were watching the spaces. Illegal parking dropped from 69.3% of 102 vehicles during the initial ground-sign condition to 57.3% of 36 vehicles in the first vertical-sign condition. Following removal of the vertical signs, illegal parking increased to 68.7% of 43 vehicles. During the second vertical-sign condition, illegal parking dropped to 53.7% of 32 vehicles, followed by an increase to 69.5% of 68 vehicles after the vertical signs were removed. The lowest rate of illegal parking (27.1% of 78 vehicles) occurred in the vertical sign-plus-message condition. Illegal parking subsequently increased to 34.6% (of 94 vehicles) when the message sign was removed, followed by an increase to 65.2% (of 105 vehicles) when the vertical signs were removed.
地面标线、地面标线加竖牌，以及带有“市民正在监督这些车位”字样的竖牌。非法停车率从最初地面标线条件下102辆车中的69.3%降至首个竖牌条件下36辆车中的57.3%。竖牌移除后，非法停车率增至43辆车中的68.7%。在第二个竖牌条件下，非法停车率降至32辆车中的53.7%，竖牌移除后又增至68辆车中的69.5%。非法停车率最低（78辆车中的27.1%）出现在竖牌加字样的条件下。当字样牌移除后，非法停车率随后增至94辆车中的34.6%，竖牌移除后又增至105辆车中的65.2%。
