The 85th percentile speed or 85th percentile rule is a traffic engineering standard used to set the speed limit for automobiles on a public roadway. It refers to a speed where 85% of vehicles travel at or below.[1][2][3]
See also[edit]
- Design speed
- Vision Zero, policy to minimize pedestrian fatalities
References[edit]
- ^ McKinley, Jesse (March 23, 2023). "Is 70 M.P.H. the New 65? Legislators Say N.Y. Roads Are Just Too Slow". The New York Times. Retrieved September 15, 2023.
States set speed limits using a variety of methods and measurements, including the so-called 85 percentile rule, which refers to the speed 'at or below which 85 percent of the drivers travel on a road segment', according to the Federal Highway Administration.
- ^ Minor, Nathaniel (September 15, 2023). "A lower speed limit could be coming to a Colorado road near you". Colorado Public Radio. Retrieved September 15, 2023.
Traditionally, U.S. traffic engineers use the '85th percentile' method that sets limits at the speed at or below which 85 percent of drivers travel in normal conditions. This federally approved approach has been used by state and local transportation agencies since at least the '60s, but street safety advocates and city transportation officials deride the method because it usually leads to higher speed limits and faster speeds, which is associated with more serious crashes.
- ^ "Setting Speed Limits". Institute of Transportation Engineers. Retrieved January 18, 2024.