On the other hand
In this study of "Checkpoint Tennessee" of the 144,299 drivers that passed through a checkpoint there were 1058 arrests for impaired driving, for a nominal yield of 0.7%. Apparently, at least in this case, the effectiveness may be more tied to the related publicity than the actual checkpoint.
Lacey, J. H., Jones, R. K., & Smith, R. G. (1999). Evaluation of Checkpoint Tennessee: Tennessee’s statewide sobriety checkpoint program. Washington, DC: US Department of Transportation, National Highway Traffic Safety Administration.
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