Road Safety Laws and Statistics

By Jane Farrell

Public support for road-safety laws can be strengthened by just one reliable statistic that proves the need for the laws, according to a new study from the Johns Hopkins Center for Injury Research and Policy at the Johns Hopkins Bloomberg School of Public Health.

The research, published in the journal of Accident Analysis & Prevention, looked at responses from 2,397 adults nationwide about four types of road-safety laws. The laws were mandatory installations of ignition locks for people convicted of driving under the influence; the use of red-light cameras in school zones; the requirement that in-vehicle information entertainment systems be disabled when a car is moving; and the mandatory use of bicycle helmets for children under 16.

After the respondents indicated whether they supported a law or not, investigators gave them a statistic about the injuries that had prompted the law or the success of the law in reducing the injury risk. The respondents were then asked about their attitude toward the laws.

For each law, participants’ support increased noticeably after they were given a statistic. Nearly a third (30.7 percent) of respondents became more supportive of the law about entertainment systems in cars; 22.2 percent increased their support for the red-light camera law, and one in five (20 percent) became more supportive of both the bicycle helmet and ignition interlock laws.

“We are very encouraged by the results of this study, the benefits of which have potential for broad application,” says Katherine Clegg Smith, PhD, lead author of the study. “In our analysis, research-informed evidence considerably increased public support for safety initiatives that are known to make a difference. Knowing that scientific evidence influences public opinion provides support for continuing to generate and share research on injury prevention policies to better inform the public about key safety issues.”