The Controlled Access Highway Task Force of 135 New York State Police patrolled 600 miles of Interstate Highway as part of a grant from the Governor's Traffic Safety Committee funded by the National Highway Traffic Safety Administration. The objectives of the grant were to reduce accidents and highway speed and to investigate enforcement techniques. Trooper and patrol vehicle performance indicators, speed surveys, and accident and injury frequency data were collected during a baseline and three experimental periods. Three types of patrol vehicle visibility (marked, an even mixture of marked and unmarked, and unmarked) were randomly assigned to 18 nominal 10-mile and 18 nominal 20-mile highway segments across New York State using a 3 x 2 factorial design. In addition, the three visibility strategies were assigned at random to three experimental periods using a cross-over design. Finally, a quasi-experimental design with the New York Thruway as a comparison was used to analyze accident frequency. The results of the program indicate that highway speeds were reduced during the program. Unmarked and an even mixture of marked and unmarked patrol vehicles showed better speed enforcement tendencies than exclusive use of marked patrol vehicles. Accident frequency was reduced by an average of 22 accidents per month during the first experimental period for the 600 miles of Interstate highway patrolled. Although accident frequency reductions were also experienced during the second and third experimental periods, these were not statistically significant. In addition, the 18 nominal 20-mile segments had a statistically significant reduction in average accident frequency during the first and third experimental periods of 12 and 10 accidents per month, respectively. No statistically significant reductions in accident frequency were observed on the 18 nominal 10-mile highway segments. It was found that both the nominal 10- and 20-mile highway segments experienced accident frequency reductions during the first experimental period when patrolled exclusively by marked and an even mixture of marked and unmarked patrol vehicles. Finally, it was determined by correlation analysis that highway segments where more patrol time was dedicated to a segment and arrest activity was higher experienced lower accident frequency.

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Filing Info

  • Accession Number: 00391800
  • Record Type: Publication
  • Source Agency: National Highway Traffic Safety Administration
  • Report/Paper Numbers: HS-037 209
  • Contract Numbers: PT-77-010
  • Files: HSL, TRIS, USDOT
  • Created Date: Jan 30 1985 12:00AM