The posted speed limit in school zones is 20 mph (32 kph), and various types of signs that inform drivers of the school-zone speed limit are in use. This study examined the effect of different types of school-zone speed-limit signs and the effect of different speed limits on the roads approaching the schools. Four types of speed-limit signs at 40 elementary schools in Washington state were assessed: signs indicating specific times of the day for the 20-mph (32-kph) speed limit; signs with yellow flashing lights on the sign post that indicated the 20-mph (32-kph) limit was in effect; signs indicating the 20-mph (32-kph) limit was in effect when children are present; and signs indicating that the 20-mph (32-kph) limit was in effect when orange flags were attached to the sign post. These sign types were categorized into groups by the posted speed limit approaching the schools: 25 mph (40 kph) and 35 mph (56 kph). Even though approximately half of the vehicles in the study were in compliance with the 20-mph (32-kph) speed limit in school zones, a major finding of the study was that many vehicles were measured at speeds greater than 35 mph (56 kph). School zones with faster approach speed limits were associated with substantially higher speeds during the half-hour critical time periods just before and just after school hours. However, flashing-light school-zone signs were effective in slowing vehicles. The average speed at schools with these signs was 5-7 mph (8-11 kph) slower than at schools with "when children are present" and flagged signs.

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  • Corporate Authors:

    Institute of Transportation Engineers (ITE)

    Washington, DC  United States 
  • Authors:
    • Saibel, C
    • Salzberg, P
    • Doane, R
    • Moffat, J
  • Publication Date: 1999-11


  • English

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Filing Info

  • Accession Number: 00779692
  • Record Type: Publication
  • Files: TRIS, ATRI
  • Created Date: Dec 22 1999 12:00AM