摘要：Objective. We evaluated the cost-effectiveness of a package of roadway modifications in New York City funded under the Safe Routes to School (SRTS) program. Methods. We used a Markov model to estimate long-term impacts of SRTS on injury reduction and the associated savings in medical costs, lifelong disability, and death. Model inputs included societal costs (in 2013 US dollars) and observed spatiotemporal changes in injury rates associated with New York City’s implementation of SRTS relative to control intersections. Structural changes to roadways were assumed to last 50 years before further investment is required. Therefore, costs were discounted over 50 consecutive cohorts of modified roadway users under SRTS. Results. SRTS was associated with an overall net societal benefit of $230 million and 2055 quality-adjusted life years gained in New York City. Conclusions. SRTS reduces injuries and saves money over the long run. In the United States, motor vehicle crashes are the leading cause of death for children aged 8 to 19 years, and the second leading cause of death for children aged 4 to 7 years. 1–3 Virtually all motor vehicle-related pedestrian injuries are preventable. One way of reducing childhood motor vehicle injury is to improve roadway safety. 4–7 However, roadway improvements require a large up-front investment, and the chance of a child being severely injured in any given intersection is relatively small. Nevertheless, such improvements remain in place for decades, producing long-term benefits on a single investment. Given the high cost but the long-term benefits, there is uncertainty surrounding the cost-effectiveness of roadway improvements. One roadway improvement program is Safe Routes to School (SRTS). 8–10 SRTS was enacted under the federal Safe, Accountable, Flexible and Efficient Transportation Equity (SAFETEA) Act in 2005 (Pub L No. 109-59). SRTS was a $612 million dollar program that funded state departments of transportation to build new sidewalks and bicycle lanes, improve safety at crossings (e.g., via traffic calming measures), upgrade signage, and enhance pedestrian education. 8,12 The intent of SRTS was to encourage children to walk and bike to school by making school travel safer, thereby reducing an important barrier to commuting outside of a vehicle. Capital improvement projects were funded at 10 400 schools in the United States. In 2012, Congress enacted Moving Ahead for Progress in the 21st Century (MAP-21; Pub L No. 112-141) to replace the SAFETEA. As a result, dedicated funding for SRTS ended, though the program may continue under discretionary funding at the state and local level. Approximately $10 million in the initial wave of funding went to the New York City Department of Transportation, which introduced safety improvements at 124 schools with the highest injury rates. 11 SRTS has been evaluated using a variety of techniques, including a difference in difference design and a Bayesian changepoint analysis. 5 SRTS has been found to produce an 11% increase in active transport to school (walking or biking) while simultaneously leading to a 33% to 44% reduction in school-age injury rates in high-risk intersections within New York City. 5,12,13 Among all users of these intersections, injury reduction rates were more modest, with about a 14% decline. 5 This analysis assesses the cost-effectiveness of SRTS in preventing pedestrian injuries among school-aged children traveling to and from school (the intent of the program) relative to the status quo. We examined this subpopulation because it is the target of the SRTS legislation. We also examined the cost-effectiveness of SRTS for all users at all times. This latter analysis provides the overall societal benefits of the program, whether intended or not.
