A study is described which was designed to determine if specific treatments on a section of a (NC-55) 2-lane rural roadway could extend the halo effect (the effect on driver behaviour beyond the point and time when enforcement is applied or when an enforcement symbol is observed). The study was done simultaneously with a study to evaluate a visual speed indicator (VSI) sign. The initial evaluation of the VSI was to determine whether the sign display would alter driver speed characteristics without police enforcement. The details of enforcement techniques, data collection and analysis techniques are outlined, and the results are presented. It was found that the use of a speed enforcement scene, a speed check zone, or a patrol vehicle produces substantial and significant reductions in mean, median, and 85th percentile speeds in the vicinity. All 3 enforcement techniques significantly reduce the percentage of vehicles travelling faster than 88.5 km/h (55 mph), as well as reduce the speed of all vehicles to the point of increasing the percentage of vehicles travelling slower than 72.4 km/h (45 mph). It was found that the VSI sign has no significant effect, and that the helo effect began to disappear 1,000 ft. past the enforcement treatment point and was completely gone at a point 2 miles downstream.

Media Info

  • Media Type: Digital/other
  • Features: Figures; References;
  • Pagination: pp 31-33
  • Monograph Title: Highway safety, traffic records, and law enforcement
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00157803
  • Record Type: Publication
  • ISBN: 0309025842
  • Files: TRIS, TRB
  • Created Date: Sep 28 1977 12:00AM