title: A new look at NHTSA's evaluation of the 1984 Charlottesville Sobriety Checkpoint Program: implications for current checkpoint issues.
abstract: OBJECTIVE
  Currently, the implementation of sobriety checkpoint programs, which have been demonstrated to be effective in reducing alcohol-related crashes, is limited by the belief that they require large consignments of police officers and result in few arrests. However, one of the earliest evaluations of a checkpoint program in Charlottesville, Virginia, demonstrated that effective checkpoints could be mounted in which police officers made as many arrests as officers on regular patrols. That study was printed by the NHTSA but was not published in a peer-reviewed journal. Because of its significance to current issues in the staffing of and procedures for checkpoint operations, this article reanalyzes the results of that study and describes the procedures implemented in checkpoints.
  
  
  METHODS
  A before-and-after control design was used to measure the change in nighttime crashes from three baseline years to the program year. Two analyses were conducted: the first on the percentage of all crashes occurring at night in the test city--Charlottesville--and the second on the percentage of all nighttime crashes in the state of Virginia that occurred in the test city. In addition, three waves of random-digit-dialing telephone surveys were conducted: one before and two during the checkpoint program in the test city, and the comparison city, Blacksburg. Finally, the number of impaired-driving arrests per officer hour at the checkpoints was compared with the number of arrests per hour by officers on regular patrol and the effect on arrests of the use of passive sensors was determined.
  
  
  RESULTS
  The monthly percentage of nighttime crashes in Charlottesville was reduced by 17% (p = 000) in relation to the baseline level. The percentage of nighttime crashes in the state of Virginia that occurred in Charlottesville was reduced by 11% (p = .013) from baseline levels. Drivers arrested at checkpoints had lower BACs than those arrested by the regular patrols; however, the conviction rates were the same. The arrest per officer hour did not differ significantly between the two types of enforcement operations. Awareness of the checkpoint activity was high (72%) among nighttime at-risk drivers in the test city. Half reported seeing a checkpoint operation, and a quarter reported being interviewed. Use of a passive alcohol sensor by officers at the checkpoint increased arrests by almost a factor of three.
  
  
  CONCLUSIONS
  The results of the evaluation suggest that small-scale sobriety checkpoints can be implemented as part of the regular enforcement program in moderate-sized jurisdictions and that they can be as efficient in producing arrests as standard enforcement patrols, particularly if passive alcohol sensors are used.
authors.affiliation: Pacific Institute for Research and Evaluation, Calverton, Maryland, USA. voas@pire.org
authors.forename: Robert B
authors.initials: RB
authors.lastname: Voas
mesh_terms: D000063:Accidents, Traffic / Q000517:prevention & control*; D000428:Alcohol Drinking / Q000331:legislation & jurisprudence*; D000435:Alcoholic Intoxication / Q000175:diagnosis; D001944:Breath Tests; D000431:Ethanol / Q000097:blood*; D005069:Evaluation Studies as Topic; D006077:Government Agencies; D006801:Humans; D035846:Law Enforcement; D008297:Male; D009026:Mortality / Q000639:trends*; D015813:Substance Abuse Detection; D014481:United States; D014505:Urban Population
chemical_list: D000431:Ethanol