Improper Shoulder Belt Use by Maryland Drivers

Abstract

This study was undertaken to determine the types and frequency of improper shoulder belt use–with particular emphasis on belt slack—in a state where belt use is mandatory. Motion picture films of drivers approaching stop signs in Maryland were analyzed by a trained panel to ascertain belt use and misuse. Over half the drivers of 1974–1987 model vehicles were observed to be belted. Slack in shoulder belts was the most common type of misuse and was much more prevalent among drivers of domestic cars than of imported cars. For belted drivers of domestic cars, 27% had 25–50 mm of slack in their belts, and 8% had 75 mm or more. By contrast, only 5% of belted drivers of imported cars had 25–50 mm of slack, and none had 75 mm or more. The window shade slack mechanism, found only in domestic vehicles, was most often associated with the slack.