The estimates were obtained using data from the injuries that were already prevented by the safety changes made to over 100 public schools during the latter half of the Bloomberg administration under the Department of Transportation Commissioner, Janette Sadik-Khan. The authors assumed that the safety benefit conferred by these environmental changes would persist for about 50 years—the usual life of infrastructure in New York City. Not included were important sources of savings, such as reduced use of government disability programs, so the savings could be higher. While the study did not use the standard method of evaluation—randomized controlled trials—it did use much more powerful statistical techniques than are often employed in such studies. This was made possible because the authors had data on intersections before, during, and after modifications were made.
"Our study provided compelling evidence that the Safe Routes to School program has made a marked difference in improving the safety of school-age children in New York City," said Peter Muennig, MD, MPH, Mailman School associate professor of Health Policy and Management, and first author of the study.
The research was supported by the National Center for Injury Prevention and Control, Centers for Disease Control and Prevention (grants 1 R21 CE001816 and 1 R49 CE002096); the National Institute on Drug Abuse, National Institutes of Health (grant DA029670), and the Center for Injury Epidemiology and Prevention, Columbia University. The authors declare no conflict of interests.