This study was designed to determine whether the display of a warning sign designating a speed check zone can affect the speed characteristics of drivers traveling through the zone. Two test sections of highway, one 20 miles long and the other 12 miles long, were chosen which reflected a difference in roadway type. Five speed monitoring stations were established for each test site in order to determine the speed of traffic along the road. Speed data were gathered under three specified conditions for both directions of traffic: (a) warning signs were displayed between the first and second speed measuring stations in addition to the prominent display of a patrol car on the shoulder of the road at the middle station, (b) the same as (a) but no sign was displayed, and (c) where neither sign nor patrol car was displayed. Several methods were used to analyze the data, including an examination of the mean speeds, variances, cumulative speed distributions, and percentage of vehicles exceeding the posted speed limit for each condition. The data reflected an alteration in the motorists' driving performance due to the display of the patrol car, as evidenced by a lower mean speed, smaller percentage of cars exceeding the legal speed limit, and more compact cumulative speed distributions. This was observed only at the sites where the patrol car was displayed. It was hypothesized that the speed check zone sign would extend the "halo effect" associated with the display of a patrol car. The "halo effect" is characterized by drivers typically correcting any unlawful actions for approximately one miel after observing a patrol vehicle, then reverting to their previous actions. However, there was no apparent reaction to the display of the speed check zone sign, and the "halo effect" was not extended. Therefore, it was concluded that the speed check zone sign had very little, if any, effect upon the drivers who encountered it. Recommendations are made which are designed to increase the likelihood that the use of sign will result in the desired reaction in the future. /Author/

  • Corporate Authors:

    University of North Carolina, Chapel Hill

    Highway Safety Research Center
    Chapel Hill, NC  United States  27599
  • Authors:
    • Hunter, W W
    • Bundy, H L
  • Publication Date: 1975-6

Media Info

  • Features: Figures; References; Tables;
  • Pagination: 47 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00145112
  • Record Type: Publication
  • Source Agency: National Safety Council Safety Research Info Serv
  • Files: TRIS
  • Created Date: Apr 13 1977 12:00AM