Recent Traffic Studies
- Kings Road - August 14, 2023 through August 20, 2023
- North Street - May 31, 2023 through June 6, 2023
- Elm Street - December 13, 2022 through December 24, 2022
- Noe Avenue - July 1, 2022 through July 14, 2022
- Pomeroy Road - March 15, 2022 through March 25, 2022
- Greenwood Avenue - January 25, 2022 through February 6, 2022
- Ridgedale Avenue - October 22, 2021 through October 31, 2021
- Central Avenue - August 30, 2021 through September 13, 2021
- Keep Street - July 27, 2021 through July 31, 2021
- Rosedale Avenue - July 8, 2021 through July 18, 2021
- Dean Street - June 16, 2021 through June 25, 2021
- Garfield Avenue - May 26, 2021 through June 14, 2021
- North Street - May 13, 2021 through May 22, 2021
- Loantaka Way - April 19, 2021 through April 28, 2021
- Pomeroy Road - March 30, 2021 through April 9, 2021
- Green Avenue/Garfield Avenue - November 24, 2020 through December 3, 2020
- Kings Road/Arlena Court - November 10, 2020 through November 19, 2020
- Glenwild Road - October 22 through November 1, 2020
- Glenwild Road - September 11 through September 20, 2020
- Pine Avenue - June 11 through June 16, 2020
• What does the 85th percentile speed mean?
The 85th percentile speed is the speed at or below 85 percent of vehicles travel.
Another way of looking at this is that only 15 percent of vehicles go faster than this speed and 85 percent go at or below this speed. According to a Federal Highway Administration study, all states and most local agencies use the 85th percentile speed of free flowing traffic as the basic factor in establishing speed limits.
• Why is the 85th percentile speed a good basis for the speed limit?
Studies have shown crash rates are lowest at around the 85th percentile speed. Drivers traveling significantly faster OR slower than this speed are at a greater risk for being in a crash. It is not high speeds alone that relate to crash risk; it is the variation of speed within the traffic stream.
• Would lowering the speed limit affect the speed of vehicles?
A change in the speed limit almost always changes the mean speed of traffic. However, the changes are not always proportional. For the most part, the change in the mean speed of traffic created by a change in speed limit is around 25 percent of the change in the speed limit. In other words, a speed limit increase or reduction of 6 mph (10 km/h) yields about a 1.5 mph (2.5 km/h) raising or lowering of the mean speed, respectively.
References: R. Elvik, P. Christensen, and A. Amundsen, "Speed and Road Accidents: An Evaluation of the Power Model," The Institute of Transport Economics (TOI), TOI Report 740/2004 (December 2004).
Federal Highway Administration (FHWA), Methods and Practices for Setting Speed Limits: An Informational Report