Considering Roadway Context in Setting Posted Speed Limits Academic Article uri icon


  • The National Cooperative Highway Research Program (NCHRP) Project 17-76 investigated factors that influence operating speed and safety through a review of the literature and an analysis of the relationships for speed, safety, and roadway characteristics on urban/suburban streets. That knowledge, along with a review of existing speed limit setting practices, was used to develop a Speed Limit Setting Procedure (SLS-Procedure) as well as a user manual to explain the SLS-Procedure. In addition, the SLS-Procedure was automated via a spreadsheet-based Speed Limit Setting Tool (SLS-Tool). These products will permit engineers to make informed decisions about the setting of speed limits. The SLS-Procedure is fact based and transparent, relying on a set of decision rules that consider both driver speed choice and safety associated with the roadway. The SLS-Procedure was designed to be applicable across different roadway types and contexts by having a set of unique decision rules for four combinations of roadway types and contexts: limited-access, undeveloped, developed, and full-access facilities. The SLS-Procedure uses the operating speed distribution as a starting point for the suggested speed limit, with the resulting suggested value based on consideration of roadway type, context, safety performance, and other characteristics.

published proceedings


altmetric score

  • 1

author list (cited authors)

  • Fitzpatrick, K., Das, S., Gates, T., Dixon, K. K., & Sug Park, E.

citation count

  • 5

complete list of authors

  • Fitzpatrick, Kay||Das, Subasish||Gates, Timothy||Dixon, Karen K||Sug Park, Eun

publication date

  • August 2021