15.6 Methods to Reduce Driver Speeds in School Zones

  • Traffic control devices and pavement markings are valuable for encouraging motorists to drive at lower speeds in school zones. Table 15.2 provides operational and design guidelines for school zones.
Table 15.2 Design and Operational Guidance for School Zones
Factor Guideline
Active Time ● School zone speed limits should only be in effect from:
  • 30 minutes before to 5 minutes after classes begin
  • The beginning to end of lunch periods for open campuses
  • 5 minutes before to 30 minutes after classes end
School Zone Speed Limit Value 85th Percentile Speed Recommended School Zone Speed Limit
< 55 mph No more than 15 mph below the 85th percentile speed or posted speed. Do not exceed a 35 mph school zone speed limit.
< 55 mph 20 mph below the 85th percentile speed or posted speed.
< 55 mph Implement a buffer zone to transition to a 30 mph school zone speed limit.
Length of School Speed Limit Zone
  • Minimum of 400 ft in urban areas with posted speeds ≤ 30 mph
  • 1000 ft in rural areas with posted speeds ≥ 55 mph
School Buffer Zone
  • Implement if the difference between the regulatory speed limit and the school zone speed limit is ≤ 20 mph
  • Usually 500 ft in length
  • Buffer zone beacons can be activated up to 5 minutes before school speed zone beacons.
School Entrance Warning Assembly Do not use if a school speed limit zone is present. May be used if:
  • Crash records show motorists should be advised to lower their speeds
  • Most students are transported by bus or private vehicle
  • No provisions are made for students to walk to and/or from school
  • The highway at the school driveway lacks left- or right-turn lanes, queue spillover from turning vehicles occurs, or methods to mitigate spillover have been ineffective
  • Entrances are not controlled by traffic signals
Sign and Device Choice
  • School speed limit signs with flashing lights help reduce vehicle speeds.
Speed Monitoring Displays
  • Signs that display vehicle speeds to motorists can reduce vehicle speeds.

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CONTACT:

Chris VanDyke

Research Scientist | Program Manager

chrisvandyke@uky.edu