Evaluating the Impact of Vision Zero Interventions on Pedestrian Casualties in NYC (2013-2023)

Motor vehicle crashes are a leading cause of death and injury in New York City (NYC). In 2014, the city adopted the Vision Zero (VZ) framework, a comprehensive strategy to eliminate all traffic-related fatalities. The program uses a multi-faceted approach, including infrastructure redesign, lower speed limits, and public awareness campaigns. This analysis evaluates the impact of nine distinct street-level interventions on pedestrian casualties, examining data from 2013 to 2023 and focusing specifically on intersections that received treatments between 2015 and 2021. This approach ensures that every intervention can be evaluated with at least two years of ‘before’ data and two years of ‘after’ data, allowing for a robust comparison.

Key Findings

Speed is Key:
Interventions that physically slow traffic, like Turn Traffic Calming (-27%) and Neighborhood Slow Zones (-21%), were most effective.
Give Pedestrians a Head Start:
Leading Pedestrian Interval Signals were associated with a 13% decrease in casualties.
Mixed Results:
Other common treatments showed no significant citywide impact on pedestrian safety.

A circular diagram showing the layers of the Safe System approach, including safer roads, safer speeds, safer vehicles, safer people, and post-crash care. — The Vision Zero Safe System Approach philosophy.

What Are the Vision Zero Interventions?

The analysis focuses on nine key physical and regulatory changes made to NYC streets. The table below provides a brief description of each intervention.

Descriptions of Assessed Vision Zero Interventions
Intervention	Description	Components/ Examples
Citywide Speed Limit Reduction	Default speed limit change from 30 MPH to 25 MPH.	Streets may be signed or unsigned.
Enhanced Crossing	A marked high-visibility crosswalk on calm streets with low vehicle volumes, high pedestrian traffic, and no traffic signal or stop sign.	At minimum, include high visibility crosswalk markings, daylighting on all approaches, Americans with Disabilities Act compliant pedestrian ramps, and pedestrian warning signage.
Leading Pedestrian Interval Signal	Signals that show a pedestrian walk sign before showing a green light to vehicle traffic in the same direction, giving pedestrians a head start to cross the street before car traffic.	—
Neighborhood Slow Zone	Neighborhood areas, selected based on crashes, presence of schools, and other factors, in which the speed limit has been reduced to 20 MPH.	Include road markings and signs indicating entrance to a slow zone, along with greater concentration of other interventions.
SIP Corridors	Safety-oriented engineering improvements that use multiple treatments in a street corridor.	Examples: large range of subtypes, including markings, vertical elements, signage and regulatory changes, signal changes, concrete, and landscaping.
SIP Intersection	Safety-oriented engineering improvements that use multiple treatments in a single intersection.	Same as above, but within intersections rather than along street corridors.
Speed Hump	A raised area of a roadway designed to reduce vehicle speeds.	—
Turn Traffic Calming	A traffic calming measure that guides drivers to turn more safely and increases pedestrian visibility.	Examples: hardened centerline, slow turn wedge, bike island channelization, median extension.
25 MPH Signal Retiming	A corridor where the signal progression has been changed to match the 25 MPH speed limit.	—

A photograph of a New York City intersection treated with left turn traffic calming in the form of a slow turn wedge. — Left turn traffic calming, designed to reduce left turn speeds and enforce safe turning behavior.

A photograph of a New York City intersection with an enhanced crossing in the form of high-visibility crosswalk markings and a prominent pedestrian warning sign. — Pedestrian warning signage, a major component of enhanced crossings.

Map of All Vision Zero Interventions & Pedestrian Casualties

The interactive map on the right displays the full Vision Zero history of every intersection in the city. Zoom-in and click on any intersection to see a list of the Vision Zero interventions it has received and the year each was first implemented.
Alternatively, you could switch to the “Pedestrian Casualties” view to see a choropleth map of pedestrian casualty counts across all NYC intersections between 2013 and 2023.

Citywide Pedestrian Casualty Trends

To understand the citywide context, we first examined the overall trend in pedestrian casualties across all 9,562 intersections in our study.

The number of pedestrian casualties showed a general downward trend over the study period, with a sharp, anomalous drop in 2020. This dip corresponds to the major changes in traffic patterns and pedestrian activity during the first year of the COVID-19 pandemic.
While casualties rebounded after 2020, they remained below pre-pandemic levels, suggesting that Vision Zero initiatives may be contributing to a sustained, long-term improvement in pedestrian safety.

The following charts break this down further. Each plot shows the casualty trend for intersections that ever received a particular type of intervention. This helps visualize trends within specific treatment groups and reveals that the overall citywide pattern is largely consistent across different intervention types.

Vision Zero Implementation Timeline

The Vision Zero program was rolled out in a staggered fashion, with different intersections receiving treatments in different years. Our study design leverages this staggered implementation to better isolate the causal impact of each intervention.

Nearly 25% of intersections in our data received their first Vision Zero intervention in 2016, with 2,247 intersections treated during that year.
No intersection in our data received its first Vision Zero treatment in 2021, suggesting that the program’s implementation to new intersections might have been limited in the aftermath of the COVID-19 pandemic.

A photograph of a Vision Zero Task Force meeting in an office. — The Vision Zero task force includes experts from across government agencies who meet on a biweekly basis to discuss upcoming and ongoing interventions.

Intervention-Specific Rollout

To see how each specific safety measure was rolled out over time, the charts below break down the implementation timeline for each of the nine interventions studied. Each chart shows the number of intersections that received that particular treatment for the first time in a given year. Notice how some interventions, like Neighborhood Slow Zones, were implemented heavily towards the beginning of the program’s roll-out, while others, like Street Improvement Corridors, were deployed throughout the observation period.

While the program’s expansion to new intersections paused in 2021, the work itself did not. The charts below reveal a strategic shift: instead of expanding the program’s footprint, the city began deepening the investment by layering additional safety measures onto intersections that were already part of the program.

Impact of VZ Interventions on Pedestrian Safety

Instead of just looking at intersections before and after a treatment, our staggered difference-in-difference design does something smarter: it compares the change in casualties at a treated intersection to the change in casualties at similar intersections that hadn’t received that treatment yet.

We used a negative binomial regression model to estimate the effect of each intervention on the annual count of pedestrian casualties. The results are presented as an Incidence Rate Ratio (IRR). An IRR below 1.0 suggests the intervention reduced casualties, while an IRR above 1.0 suggests it increased them.

The table below summarizes these findings. Percent changes and IRRs are colored based on the result: green for a statistically significant reduction, red for a significant increase (none in this study), and grey for no significant effect.

Impact of VZ Interventions on Pedestrian Casualties
Comparing interventions based on their estimated effect
VZ Intervention	% Change	IRR	95% CI	P-Value
Street Improvement Project Intersection	3.9%	1.039	[0.820, 1.318]	0.750
25 MPH Signal Retiming	−2.1%	0.979	[0.924, 1.037]	0.472
Leading Pedestrian Interval Signal	−12.7%	0.873	[0.818, 0.932]	<0.001
Enhanced Crossing	19.6%	1.196	[0.883, 1.619]	0.248
Street Improvement Project Corridor	−3.9%	0.961	[0.906, 1.019]	0.186
Citywide Speed Limit Reduction	−10.2%	0.898	[0.847, 0.952]	<0.001
Speed Hump	−7.4%	0.926	[0.847, 1.014]	0.097
Turn Traffic Calming	−26.7%	0.733	[0.636, 0.846]	<0.001
Neighborhood Slow Zone	−21.2%	0.788	[0.660, 0.940]	0.008

Ranking Intervention Effectiveness

The bar chart visualizes the estimated percent change in pedestrian casualties for each intervention, providing an at-a-glance summary of which strategies were most effective.

What Works Best? The most successful interventions manage vehicle speed through physical design/regulation, or enhance pedestrian visibility through a temporal decoupling of vehicular and pedestrian movement.
- Turn Traffic Calming (-26.7%)
- Neighborhood Slow Zones (-21.2%)
- Leading Pedestrian Intervals (-12.7%)
- Citywide Speed Limit Reduction (-10.3%)
What Doesn’t Work?
- 25 MPH Signal Retiming, Enhanced Crossings, Speed Humps, and SIP Intersections/Corridors had no statistically significant effect.

A photograph of a complex intersection on Sheepshead Bay Road in Brooklyn. This intersection received several Vision Zero intervetnions, including turn traffic calming and enhanced crossing. — Sheepshead Bay Road in Brooklyn: an example of a complex intersection with multiple Vision Zero interventions applied. Since these improvements, the Department of Transportation reports that total injuries decreased by 18% and crashes with injuries decreased by 24% at this intersection.

Conclusion & Policy Implications

Our analysis confirms that Vision Zero has had a tangible, positive impact on pedestrian safety, but not all interventions contribute equally. The findings provide a clear mandate for future transportation policy:

Prioritize Speed Management and Pedestrian Visibility: The most effective way to protect pedestrians is to control vehicle speed and enhance pedestrian visibility at crossings. Future investments should be heavily focused on expanding infrastructure like Neighborhood Slow Zones, Turn Traffic Calming, and Leading Pedestrian Interval Signals.
Re-evaluate Non-Significant Interventions: While out analysis indicated that five of the nine assessed interventions had no significant association with pedestrian casualties, these projects should not be outright abandoned. Instead, policymakers should conduct further investigation to evaluate whether interventions such as 25 MPH Signal Retiming and Speed Humps protect against other kinds of adverse outcomes (e.g., motorist casualties or collisions) or play a role in enhancing efficiency of traffic flow.

Ultimately, this research shows that building a safe transportation system and an efficient one are not conflicting goals. Investments in traffic calming are a core component of an efficient network that is safer and more predictable for all.

About the Data & Analysis

This analysis was conducted by the NYC Council Data Team using publicly available data from NYC Open Data, including datasets from the NYPD and the Department of Transportation. The full methodology is detailed in our to-be-published manuscript.

While our statistical model controls for many factors, traffic safety is incredibly complex. The findings represent our best estimate of the impact of these specific interventions, but other unmeasured factors could also play a role.

For feedback, comments, and questions please email DataInfo@council.nyc.gov.

Created by the NYC Council Data Team.