83 Comments

Edited by Susan Hanson, Clark University, Worcester, MA; received August 1, 2025; accepted November 4, 2025

December 8, 2025

122 (50) e2520328122

Significance

Many US cities are turning to automated speed cameras as a promising alternative to traditional traffic enforcement by police, aiming to reduce collisions without the risks of racial bias or harmful police encounters. But how effective are they? This study evaluates the largest automated speed enforcement program in the United States—2,000 cameras deployed across New York City from 2014 to 2023. Leveraging data on 700,000 collisions and 18 million speeding tickets, the analysis finds that cameras lead to persistent and sustained reductions in crashes. These results demonstrate that automated enforcement can meaningfully improve road safety while avoiding the harms associated with conventional traffic safety approaches.

Abstract

Each year, approximately 40,000 people die in vehicle collisions in the United States, generating $340 billion in economic costs. To make roads safer without expanding police contact, many cities have turned to automated traffic enforcement, cameras that detect and fine speeding motorists. Does automated enforcement reduce vehicle collisions and injuries? Many previous studies are limited to correlational evidence. By contrast, this study estimates the causal effect of automated enforcement on road safety in a difference-in-differences design. We exploit the staggered rollout of 2,000 speed cameras across New York City between 2014 and 2023, combining data on 700,000 collisions and 200,000 injuries with data on 18 million tickets issued. We find that cameras reduce collisions and injuries by 5 and 2.5% per month on average, respectively. Cumulatively, over the seven months following their introduction, collisions declined by 30% and injuries by 16%.

Get full access to this article

Purchase, subscribe or recommend this article to your librarian.

Data, Materials, and Software Availability

Replication data and code for publication data have been deposited in OSF.io (56). All other data are included in the article and/or SI Appendix.

Acknowledgments

We thank Frank Edwards for his comments on a previous version of the manuscript. All underlying data used in this study are drawn from publicly available sources cited in the paper. The authors acknowledge that they received funding support for this research from the School of Criminal Justice, Rutgers University–Newark.

Author contributions

A.S.-B., J.B.-M., and B.B. designed research; performed research; analyzed data; and wrote the paper.

Competing interests

The authors declare no competing interest.

Supporting Information

References

1

National Highway Traffic Safety Administration, “Summary of Motor Vehicle Traffic Crashes: 2022 Data” (U.S. Department of Transportation, Traffic Safety Facts Report DOT HS 813 643, 2024).

2

L. Blincoe et al., The Economic and Societal Impact of Motor Vehicle Crashes, 2019 (Revised) (National Highway Traffic Safety Administration, Report No. DOT HS 813 403, 2023).

3

National Safety Council, Injury Facts: Top 10 Preventable Injuries—Data Details (NSC, 2024).

4

Centers for Disease Control and Prevention, National Center for Health Statistics, FastStats: Homicide (CDC, 2023).

5

M. A. Yellman, E. K. Sauber-Schatz, Motor vehicle crash deaths—United States and 28 other high-income countries, 2015 and 2019. Morb. Mortal. Wkly. Rep. 71, 837–843 (2022).

6

E. Edmonds, The pandemic’s tenacious grip on traffic safety. AAA Newsroom (2024).

7

A. P. Susaneck, American Road Deaths Show An Alarming Racial Gap. (The New York Times, 2023).

8

S. A. Seo, Policing the Open Road: How Cars Transformed American Freedom (Harvard University Press, Cambridge, MA, 2019).

9

P. Aggarwal et al., High-frequency location data show that race affects citations and fines for speeding. Science 387, 1397–1401 (2025).

10

E. Pierson et al., A large-scale analysis of racial disparities in police stops across the United States. Nat. Hum. Behav. 4, 736–745 (2020).

11

F. R. Baumgartner, D. A. Epp, K. Shoub, Suspect Citizens: What 20 Million Traffic Stops Tell Us About Policing and Race (Cambridge University Press, Cambridge, 2018).

12

R. Voigt et al., Language from police body camera footage shows racial disparities in officer respect. Proc. Natl. Acad. Sci. U.S.A. 114, 6521–6526 (2017).

13

D. A. Epp, E. H. Rivera, M. Sullivan, Review of Academic Literature on Pretextual Stops (City of Pasadena, 2023).

14

D. Ang, The effects of police violence on inner-city students. Q. J. Econ. 136, 115–168 (2021).

15

J. Ben-Menachem, K. T. Morris, Ticketing and turnout: The participatory consequences of low-level police contact. Am. Polit. Sci. Rev. 117, 1252–1267 (2023).

16

A. P. Anoll, D. A. Epp, M. Israel-Trummel, Contact and Context: How Municipal Traffic Stops Shape Citizen Character. J. Polit. 84, 2272–2277 (2022).

17

N. Yancey-Bragg, Tyre Nichols’ Death is the Latest Example of a Minor Traffic Stop Turning Deadly, Experts Say. (USA Today, 2023).

18

B. Beck, Police killings and municipal reliance on fine-and-fee revenue. RSF 9, 161–181 (2023).

19

M. McIntire, M. H. Keller, The Demand for Money Behind Many Police Traffic Stops. (The New York Times, 2021).

20

J. L. Knode, T. M. Carter, S. E. Wolfe, Driving while broke: The role of class signals in police discretion. Justice Q. 42, 396–425 (2024).

21

M. D. Makowsky, T. Stratmann, Political economy at any speed: What determines traffic citations? Am. Econ. Rev. 99, 509–527 (2009).

22

National Academies of Sciences, Engineering, and Medicine, Automated Enforcement for Speeding and Red Light Running (The National Academies Press, Washington, D.C., 2012).

23

J. Gao, D. Yang, C. Xu, K. Ozbay, S. Sharma, Assessing the impact of fixed speed cameras on speeding behavior and crashes: A longitudinal study in New York City. Transp. Res. Interdiscip. Perspect. 30, 1–11 (2025).

24

D. J. Graham, C. Naik, E. J. McCoy, H. Li, Do speed cameras reduce road traffic collisions? PLoS One. 14, 1–15 (2019).

25

K. Xie, K. Ozbay, H. Yang, D. Yang, A new methodology for before-after safety assessment using survival analysis and longitudinal data. Risk Anal. 39, 1342–1357 (2019).

26

C. Wilson, C. Willis, J. K. Hendrikz, R. Le Brocque, N. Bellamy, “Speed cameras for the prevention of road traffic injuries and deaths” in Cochrane Database of Systematic Reviews, The Cochrane Collaboration (John Wiley & Sons Ltd, Chichester, UK, 2010).

27

S. L. Morgan, C. Winship, Counterfactuals and Causal Inference: Methods and Principles for Social Research (Cambridge University Press, Cambridge, MA, ed. 2, 2014).

28

J. Gallagher, P. J. Fisher, Criminal deterrence when there are offsetting risks: Traffic cameras, vehicular accidents, and public safety. Am. Econ. J. Econ. Policy. 12, 202–237 (2020).

29

C. K. Tang, Do speed cameras save lives? (Spatial Economics Research Centre, SERC Discussion Paper 221, 2017).

30

K. Willardsen, Effects of speed cameras on intersection accidents: Evidence from Dayton. RRS. 51, 266–291 (2021).

31

H. Li, Y. Zhang, G. Ren, A causal analysis of time-varying speed camera safety effects based on the propensity score method. J. Saf. Res. 75, 119–127 (2020).

32

Governor.ny.gov, Governor Hochul signs legislation expanding use of New York City school zone speed cameras (2022).

33

New York City Department of Finance, Final rule regarding speed camera violations (2013)

34

A. Bernstein, 2/3 of city streets are near schools, subject to lower speed limits. WNYC (2013).

35

Rosenblum Law, Speeding tickets in New York state (2024).

36

New York State Assembly, Assembly passes life-saving school zone speed camera legislation for New York City and Buffalo (2019).

37

Fines and Fees Justice Center, Red-light and speed cameras: Analyzing the equity and efficacy of Chicago’s automated camera enforcement program (2022).

38

J. Cuba, Analysis: New York’s speed cameras aren’t racist — but the city’s road design is. Streetsblog NYC, (2022).

39

W. Farrell, Predominantly black neighborhoods in D.C. bear the brunt of automated traffic enforcement, D.C. Policy Center (2018).

40

W. Cai et al., Measuring racial and ethnic disparities in traffic enforcement with large-scale telematics data. PNAS Nexus 1, 1–8 (2022).

41

B. C. Tefft, Impact Speed and A Pedestrian’s Risk of Severe Injury or Death (AAA Foundation for Traffic Safety, 2011).

42

New York City Comptroller, Audit report on the New York city department of transportation’s speed camera program (2024).

43

W. Xu et al., The racial composition of road users, traffic citations, and police stops. Proc. Natl. Acad. Sci. U.S.A. 121, 1–6 (2024).

44

S. M. Quintanar, Man vs. machine: An investigation of speeding ticket disparities based on gender and race. J. Appl. Econ. 20, 1–28 (2017).

45

A. J. Haddad et al., Pedestrian crash frequency: Unpacking the effects of contributing factors and racial disparities. Accid. Anal. Prev. 182, 1–15 (2023).

46

N. L. Taylor, J. M. Porter, S. Bryan, K. J. Harmon, L. S. Sandt, Structural racism and pedestrian safety: Measuring the association between historical redlining and contemporary pedestrian fatalities across the United States, 2010–2019. Am. J. Public Health 113, 420–428 (2023).

47

C. Hamann, C. Peek-Asa, B. Butcher, Racial disparities in pedestrian-related injury hospitalizations in the United States. BMC Public Health 20, 1–7 (2020).

48

I. Duncan, Traffic deaths increased during the pandemic. The toll fell more heavily on Black residents, report shows. (The Washington Post, 2021).

49

National Highway Traffic Safety Administration, Dangers of Speeding (U.S. Department of Transportation, 2023).

50

S. Openshaw, “The modifiable areal unit problem” in Classification Using Information Statistics (Geo Books, Norwich, UK, 1983).

51

B. Callaway, P. H. C. Sant’Anna, Difference-in-differences with multiple time periods. J. Econometrics 225, 200–230 (2021).

52

L. Sun, S. Abraham, Estimating dynamic treatment effects in event studies with heterogeneous treatment effects. J. Econometrics. 225, 175–199 (2021).

53

A. Goodman-Bacon, Difference-in-differences with variation in treatment timing. J. Econometrics 225, 254–277 (2021).

54

T. Roemer, School shootings increase NRA donations. Sci. Adv. 9, 1–8 (2023).

55

S. H. Preston, P. Heuveline, M. Guillot, Demography: Measuring and Modeling Population Processes (Wiley-Blackwell, Malden, MA, 2000).

56

A. Stagoff-Belfort, J. Ben-Menachem, B. Beck, Can cameras make streets safer? Quasi-experimental evidence from New York City. Open Science Framework. https://doi.org/10.17605/OSF.IO/D5XVZ. Deposited 29 April 2025.