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The impact of license plate recognition technology (LPR) on trust in law enforcement: a survey-experiment



We examine the extent to which individuals' knowledge of an advanced police technology (license plate recognition or "LPR") may impact perceptions of police. Technologies with the capacity to track individuals' movements are becoming increasingly common in police practice. Although these technologies may yield positive benefits, their use may also heighten community concerns about increased surveillance, data storage, and data security, thereby potentially negatively impacting community-police relationships.


We utilize a survey-based experiment with randomized assignment of participants (n=405) to investigate the impact of individuals' knowledge of LPR use on a variety of police perceptions, including trust in police, community approval, respect for citizens, and respect for individual rights.


Most respondents were unaware of LPR use prior to the survey. When compared with a control group, respondents who encountered brief mentions of LPR functions on the survey expressed significantly lower levels of trust in police. Additionally, "strong agreement" with other positive statements about police also appears to have declined in this sample in response to LPR information. Notably, the sample contained high pre-existing levels of trust and support for police, factors which may have moderated the impacts of LPR information.


These results support the hypothesis that awareness of LPR use may negatively impact perceptions of police, including trust in police. More generally, although technologies like LPR represent technological innovations, they may also yield unintended consequences, including the potential to undermine police-community relations if adoption decisions are not accompanied by sufficient transparency or community support.

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  1. For a fuller explanation of the survey methodology, sample characteristics, and limitations, see the online only technical appendix.

  2. The full wording of these items is detailed later in this section and in the online only technical appendix.

  3. These results may be found in the online only technical appendix.

  4. Given the imbalance between the conditions, we ran regression analyses as a sensitivity check of our results, but found the results to hold after controlling for demographic and other characteristics. These results may be found in the online only technical appendix.


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Correspondence to Linda M. Merola.

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Merola, L.M., Lum, C. & Murphy, R.P. The impact of license plate recognition technology (LPR) on trust in law enforcement: a survey-experiment. J Exp Criminol 15, 55–66 (2019).

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