WED-120 - Returns on investment for leading pedestrian intervals for pedestrian safety in New York City
Wednesday, April 16, 2025
6:00 PM – 7:00 PM PST
Location: Pacific I/II, 2nd Floor
Subcompetencies: 4.1 Design research studies 4.3 Manage the collection and analysis of evaluation and/or research data using appropriate technology 4.4 Interpret data 4.5 Use findings, Research or Practice: Research
Doctoral Student Columbia University , New York, United States
Learning Objectives:
At the end of this session, participants will be able to:
To learn epidemiological and economic methods for evaluating policies and programs.
To communicate research findings to broader public health audience, beyond areas of expertise, i.e., spatial epidemiology.
To collaborate with city officials for building research-to-policy pipelines.
Road traffic crashes are a leading cause of morbidity and mortality in New York City (NYC). Under the Vision Zero initiative, NYC has implemented multiple physical environmental interventions including leading pedestrian intervals (LPIs). LPIs are premised to reduce vehicle-pedestrian crashes by providing pedestrians a head-start over the turning vehicular traffic. Previous small sample assessments in NYC and beyond have found that LPIs are associated with crash reductions. However, a large and methodologically sound assessment of effectiveness and more importantly the economic returns that can drive health policymaking and urban planning are missing. We assessed the returns on investment (ROI) of city-wide NYC sample of LPIs for pedestrian safety outcomes. Our analyses included two parts. In the first part, we assessed the effectiveness of LPIs on fatal and non-fatal pedestrian injuries at and around intersections from 2013 to 2018. We used a spatial ecological panel design with appropriate control units, i.e., intersection-months that are not-yet-treated for LPI. We estimated injury risk using mixed effects logistic regression models. The absolute risk reduction (ARR) values per intersection-year from the first part were used in the second part that assessed the economic ROI. Economic benefits were estimated by multiplying the ARR with the unit economic cost of pedestrian injury as per the US Federal Highway Administration. For non-fatal injuries, we conducted multiple sensitivity analyses assuming different levels of injury severity: severe, serious, and moderate. The cost of LPI installation ($1200) was annualized assuming a 3% discount rate and 10-year service span, giving $141. Annual ROI was the ratio of net benefit to the cost. We acquired data from public sources, published academic literature, and government reports. We included 6,003 intersections (2,869 LPI-treated) and 36,018 intersection-years. From 2013 to 2018, there were 25,899 total injuries of which 291 were fatal. We observed substantial reductions in fatal (ARR = -0.0032998 [95% Confidence Interval: -0.006054, -0.0005456]), and non-fatal injuries (-0.0657541 [-0.0841308, -0.0473775]). These translated to annual benefits (per intersection-year) worth $4876 [$806, $8945] for averted fatal injuries resulting in an ROI of 33.66 [4.73, 62.59]. Across different sensitivity analyses, the benefits for non-fatal injuries ranged from $5444 [$3922, $6965] (if all injuries were moderate) to $47749 [$34404, $61093] (if all were severe). The corresponding ROI varied from 37.70 [26.88, 48.51] (moderate injuries) to 338.42 [243.56, 433.28] (severe injuries). This novel large-scale assessment for New York City noted LPIs as an effective and cost-beneficial intervention to improve pedestrian safety outcomes. Future research should assess economic returns of packaging interventions such as turn-traffic calming with leading pedestrian intervals.
