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License plate reader (LPR) police patrols in crime hot spots: an experimental evaluation in two adjacent jurisdictions

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Abstract

Objectives

This randomized controlled experiment tests whether license plate readers (LPR) deter crime generally, and automobile crime more specifically in crime hot spots. The limited intervention tested here reflects one current likely use of LPR at the time of this publication.

Methods

We use a place-based block randomized experiment. Our subjects were 30 hot spots in two jurisdictions, 15 which were assigned to experimental conditions. The treatment involved targeted police patrols using a "sweep and sit" approach with license plate readers in these hot spots, also applying the Koper Curve timing principle. We examine effects of the intervention during and in a 30-day period post-intervention, controlling for pre-intervention levels of crime, seasonal factors, and jurisdiction.

Results

Our findings indicate that, when small numbers of LPR patrols are used in crime hot spots in the way we have tested them here, they do not seem to generate either a general or offense-specific deterrent effect.

Conclusions

While we did not find significant findings of this intervention, a number of limitations and caveats to this study must be considered in conjunction with these findings. The authors suggest how already acquired LPRs might be used in ways that might increase their effectiveness in crime hot spots.

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Notes

  1. In some agencies, officers still carry paper lists of stolen vehicles against which to check suspicious vehicles prior to calling the dispatch center.

  2. ArcGIS is a product of the ESRI Corporation (see www.esri.com).

  3. The final geocoding match rate of crime data addresses to x–y coordinates was 91.6% for FCPD and 99.5% for APD. The lower match rate for FCPD could reflect a number of factors, although we suspect it is due to FCPD’s relative newness to crime analysis, mapping, and a new records management system. It may also be due to the varied and expanded geographic terrain of Fairfax County compared with Alexandria City.

  4. CrimeStat is a free spatial analysis program available through the National Institute of Justice and the Inter-university Consortium for Political and Social Research (ICPSR). See http://www.icpsr.umich.edu/icpsrweb/CRIMESTAT/ for details on the program.

  5. There were days during the experimental period in which officers were not available, which extended both experiments in each jurisdiction further than anticipated.

  6. The start date of the experiment was delayed due to the historic 2010 Washington D.C. area snowstorm. Although most of the snow and ice had been cleared from the roads before the evaluation started, road salt and debris did affect the effectiveness of the plate readers, and snow banks blocked officer access to some parts of hot spots during the first few days of the evaluation. Another factor in the delay was the transition to a new records management system in one of agencies.

  7. The two assigned officers from APD worked opposite patrol shifts (day/evening); thus, although they may have conducted patrols on the same day, there was no overlap of coverage.

  8. One of the two LPR officers in Alexandria may not have turned off the LPR device in-between hot spots and reported plate read numbers that were unusually high on some days. Although we had the start and end number for reads for the day, we could not be sure that the LPR was not used outside the hot spots (i.e., plates read in between hot spots). Thus, the average for the number of plates scanned in Alexandria was calculated using only one officer’s reported numbers.

  9. Weekly trends of all crimes for Alexandria from the week of November 15, 2009 (“Week 1”) through the week of June 30, 2010 (“Week 32”) and for Fairfax County from the week of December 26, 2009 (“Week 1”) through the week of May 20, 2010 (“Week 21”).

  10. The large percent differences are due to the low base rates of crime in each experimental and control hot spots.

  11. Again, when including the interaction effect between the intervention and the location of the hot spot, no substantive changes were discovered, with the exception of the significance of the independent jurisdiction effect, which became less significant and greater than.05. It appears that hot spots in Alexandria either during the treatment period or after, had less auto-related thefts recorded in the hot spots, independent of whether the hot spot received or had more or less auto-related crimes during the pre-intervention period or during the year prior.

  12. International Association of Chiefs of Police (2007). Support for License Plate Reader Systems. Accessed May 24, 2010 from the International Association of Chiefs of Police website: http://www.iacp.org/resolution/index.cfm?fa=dis_public_view&resolution_id=324&CFID=9952799&CFTOKEN=30183528

  13. In a recent report by USA Today, a spokesperson for ELSAG, one of the major manufacturers of LPR systems, estimated that approximately 40 agencies in the DC metropolitan are using LPR systems.

References

  • Bailey, T., & Gatrell, A. (1995). Interactive Spatial Data Analysis. Harlow: Pearson.

    Google Scholar 

  • Barclay, P., Buckley, J., Brantingham, P. L., Brantingham, P. J., & Whinn-Yates, T. (1995). Preventing auto theft in suburban Vancouver commuter lots: Effects of a bike patrol. In R. Clarke (Ed.), Crime prevention studies (Vol. 6). Monsey: Criminal Justice Press.

    Google Scholar 

  • Boruch, R., De Moya, D., & Snyder, B. (2000). The importance of randomized field trials. Crime and Delinquency, 46(2), 156–180.

    Article  Google Scholar 

  • Braga, A., & Bond, B. J. (2008). Policing crime and disorder hot spots: A randomized controlled trial. Criminology, 46(3), 577–607.

    Article  Google Scholar 

  • Braga, A., Weisburd, D., Waring, E., Green Mazerolle, L., Spelman, W., & Gajewski, F. (1999). Problem-oriented policing in violent crime places: A randomized controlled experiment. Criminology, 37(3), 541–580.

    Article  Google Scholar 

  • Brantingham, P. J., & Brantingham, P. L. (Eds.). (1981). Environmental criminology. Beverly Hills: Sage.

    Google Scholar 

  • Chan, J. (2003). Police and New Technologies. In T. Newburn (Ed.), The Handbook of Policing. Collompton: Willan.

    Google Scholar 

  • Clarke, R., & Weisburd, D. (1994). Diffusion of Crime Control benefits: Observations on the reverse of displacement. In R. Clarke (Ed.), Crime Prevention Studies Vol. 2 (pp. 165–183). Monsey: Willow Tree Press.

    Google Scholar 

  • Cohen, Plecas, & McCormick (2007). A report on the utility of the automated license plate recognition system in British Columbia. Unpublished report

  • Copes, H. (1999). Routine activities and motor vehicle theft: A crime specific approach. Journal of Crime and Justice, 22(2), 125–146.

    Google Scholar 

  • Durlauf, S. N., & Nagin, D. S. (2011). Overview of “Imprisonment and crime: Can both be reduced?”. Criminology & Public Policy, 10(1), 9–12.

    Article  Google Scholar 

  • Ericson, R. V., & Haggerty, K. D. (1997). Policing the Risk Society. Toronto: University of Toronto Press.

    Google Scholar 

  • Felson, M., & Poulsen, E. (2003). Simple indicators of crime by time of day. International Journal of Forecasting, 19, 595–601.

    Article  Google Scholar 

  • Gardner, W., Mulvey, E., & Shaw, E. (1995). Regression analyses of counts and rates: Poisson, overdispersed poisson, and negative binomial models. Psychological Bulletin, 118(3), 392–404.

    Article  Google Scholar 

  • International Association of Chiefs of Police. (2009). Privacy impact assessment report for the utilization of license plate readers. Alexandria: International Association of Chiefs of Police.

    Google Scholar 

  • Koper, C. (1995). Just enough police presence: Reducing crime and disorderly behavior by optimizing patrol time in crime hot spots. Justice Quarterly, 12(4), 649–672.

    Article  Google Scholar 

  • Koper, C., Taylor, B., & Kubu, B. (2009). Law enforcement technology needs assessment: Future technologies to address the operational needs of law enforcement. Washington, DC: Police Executive Research Forum.

    Google Scholar 

  • Lu, Y. (2003). Getting away with the stolen vehicle: An investigation of journey-after-crime. The Professional Geographer, 55(4), 422–433.

    Article  Google Scholar 

  • Lu, Y., & Thill, J. (2003). Assessing the cluster correspondence between paired point locations. Geographical Analysis, 35(4), 290–309.

    Google Scholar 

  • Lum, C. (2009). Translating police research into practice. Ideas in American Policing, 11, 1–16.

    Google Scholar 

  • Lum, C. (2010). Gadgets for gathering evidence are not evidence of better policing. Science Progress, Accessed June 1, 2010 from the Science Progress website: http://www.scienceprogress.org/2010/02/police-technology/.

  • Lum, C., Koper, C. & Telep, C. (2009). The evidence-based policing Matrix. Online Tool. Located at http://gemini.gmu.edu/cebcp/matrix.html.

  • Lum, C., Merola, L., Hibdon, J., & Cave, B. (2010). License Plate Recognition Technologies for Law Enforcement: An Outcome and Legitimacy Evaluation. SPAWAR and National Institute of Justice. http://gemini.gmu.edu/cebcp/LPR_FINAL.pdf.

  • Lum, C., Koper, C., & Telep, C. (2011). The evidence-based policing Matrix. Journal of Experimental Criminology, 7(1), 3–26.

    Article  Google Scholar 

  • Maryland State Highway Authority (2005). Evaluation of license plate recognition system. Accessed November 11, 2009 from the American Association of State Highway and Transportation Officials website: http://www.transportation.org/sites/ssom/docs/LPR_report_part3.pdf.

  • Maxfield, M., & Clarke, R. V. (Eds.). (2004). Understanding and preventing car theft (Crime prevention studies, Vol. 17). Monsey: Criminal Justice Press.

    Google Scholar 

  • Melbin, M. (1978). Night as frontier. American Sociological Review, 43(1), 3–22.

    Article  Google Scholar 

  • Nagin, D. S. (1998). Criminal deterrence research at the outset of the twenty-first century. Crime and Justice, 23, 1–42.

    Article  Google Scholar 

  • National Research Council (2004). Fairness and effectiveness in policing: The evidence. Committee to Review Research on Police Policy and Practices. W. Skogan & K. Frydl (eds.). Committee on Law and Justice, Division of Behavioral and Social Sciences and Education. Washington, DC: National Academies Press.

  • Home Office. (2007). Police Standards Unit: Evaluation of Automatic Number Plate Recognition 2006/2007. London: PA Consulting Group.

    Google Scholar 

  • Ohio State Highway Patrol (2005). Automatic plate reader technology. Planning Services Section Research and Development.

  • PA Consulting Group. (2003). Engaging criminality – Denying criminals the use of the road. Great Britain. London, UK: PA Consulting Group.PA Consulting Group. (2006). Police Standards Unit: Thematic review of the use of automatic number plate recognition within police forces. London, UK: PA Consulting Group.

  • PA Consulting Group. (2004). Driving crime down – Denying criminals the use of the road. Great Britain, Home Office. Accessed July 21st, 2009 from http://police.homeoffice.gov.uk/news-and-publications/publication/operational-policing/Driving_Crime_Down_Denyin1.pdf?view=Binary.

  • Pierce, G., Spaar, S., & Briggs, L. (1988). The character of police work: Strategic and tactical implications. Boston: Center for Applied Social Research.

    Google Scholar 

  • Rengert, G. (1997). Auto theft in central Philadelphia. In R. Homel (Ed.), Policing for Prevention: Reducing Crime, Public Intoxication, and Injury (pp. 199–220). Monsey: Criminal Justice Press.

    Google Scholar 

  • Sherman, L. W. (1990). Police Crackdowns: Initial and Residual Deterrence. Crime and Justice: A Review of Research, 12, 1–48.

    Article  Google Scholar 

  • Sherman, L. W. (1998). Evidence-based policing (Ideas in American Police Series). Washington, DC: The Police Foundation.

    Google Scholar 

  • Sherman, L. W., & Weisburd, D. (1995). General deterrent effects of police patrol in crime "hot spots": A randomized controlled trial. Justice Quarterly, 12(4), 626–648.

    Google Scholar 

  • Sherman, L. W., Gartin, P., & Buerger, M. (1989). Hot spots of predatory crime: Routine activities and the criminology of place. Criminology, 27(1), 27–56.

    Article  Google Scholar 

  • Sherman, L. W., Gottfredson, D., MacKenzie, D. L., Eck, J., Reuter, P., & Bushway, S. (1997). Preventing crime: What works, what doesn’t, what’s promising: A report to the United States Congress. Washington, DC: National Institute of Justice.

    Google Scholar 

  • Sherman, L. W., Farrington, D. P., Welsh, B. C., & MacKenzie, D. L. (2002). Evidence-based crime prevention. New York: Routledge.

    Google Scholar 

  • Taylor, B., Koper, C., & Woods, D. (2011). Combating auto theft in Arizona: A randomized experiment with license plate recognition technology. Final Report to the National Institute of Justice. Washington, DC: Police Executive Research Forum.

    Google Scholar 

  • Weisburd, D. (2000). Randomized experiments in criminal justice policy: Prospects and problems. Crime and Delinquency, 46(2), 181–193.

    Article  Google Scholar 

  • Weisburd, D. (2002). From criminals to criminal contexts: Reorienting criminal justice research and policy. Advances in Criminological Theory, 10, 197–216.

    Google Scholar 

  • Weisburd, D. (2008). Place-based policing. Series on Ideas in American policing. Washington, DC: The Police Foundation.

    Google Scholar 

  • Weisburd, D., & Eck, J. E. (2004). What can police do to reduce crime, disorder, and fear? The Annals of the American Academy of Political and Social Science, 59(1), 42–65.

    Article  Google Scholar 

  • Weisburd, D., & Green, L. (1995). Policing drug hot spots: The Jersey City Drug Market Analysis experiment. Justice Quarterly, 12(4), 711–735.

    Article  Google Scholar 

  • Weisburd, D., & Lum, C. (2005). The Diffusion of Computerized Crime Mapping in Policing: Linking Research and Practice. Police Practice and Research: An International Journal, 6(5), 419–434.

    Article  Google Scholar 

  • Weisburd, D., Bushway, S., Lum, C., & Yang, S. (2004). Trajectories of crime at places: A longitudinal study of street segments in the city of Seattle. Criminology, 42(2), 283–321.

    Article  Google Scholar 

  • Weisburd, D., Wyckoff, L., Ready, J., Eck, J., Hinkle, J., & Gajewski, F. (2006). Does Crime Just Move Around the Corner? A Controlled Study of Spatial Displacement and Diffusion of Crime Control Benefits. Criminology, 44(3), 549–592.

    Article  Google Scholar 

  • Weisburd, D., Bernasco, W., & Bruinsma, G. (Eds.). (2009). Putting crime in its place. New York: Springer.

    Google Scholar 

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Correspondence to Cynthia Lum.

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Lum, C., Hibdon, J., Cave, B. et al. License plate reader (LPR) police patrols in crime hot spots: an experimental evaluation in two adjacent jurisdictions. J Exp Criminol 7, 321–345 (2011). https://doi.org/10.1007/s11292-011-9133-9

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