As Bike to Work week continues, New Yorkers got some good news from a team of researchers at Columbia University's Mailman School of Public Health. Using funds from the federally funded Safe Routes to School program enacted in 2005 in an effort to create safe environments for American children to walk or bike to school, New York City made safety changes to the most dangerous intersections near schools. These interventions included narrowing intersections by building out sidewalks, setting off dedicated bicycle lanes, and installing speed humps, and timing lights so pedestrians have more time to cross. The program, which was de-funded last year by Congress, cost $10 million but will bring about an overall net societal benefit of $230 million (in 2013 value) saved and 2055 quality-adjusted life years gained in New York City, according to the study.

Findings are in the May 15 online edition of the American Journal of Public Health.

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.