USLIMITS2 is of particular benefit to local communities and agencies without ready access to engineers experienced in conducting speed studies for setting appropriate speed limits. For experienced engineers, USLIMITS2 can provide an objective second opinion and increase confidence in speed limit setting decisions. USLIMITS2 was developed based on research through National Cooperative Highway Research Program (NCHRP) Project 3-67 and considers all major factors used by practitioners to make engineering judgment in determining an appropriate speed limit. This includes: operating speed (50th and 85th percentile), annual average daily traffic, roadway characteristics and geometric conditions, level of development in the area around the road, crash and injury rates, presence of on-street parking, and extent of ped/bike activity, as well as several others depending on the road type. These factors are further described in the User Guide, NCHRP 3-67 report, and Decision Rules documentation.ĭisclaimer: The U.S. Government assumes no liability for the use of the information contained in this tool. This tool does not constitute a standard, specification, or regulation. USING USLIMITS2īefore beginning a new project, it is recommended that you read through the User Guide and be prepared to enter the necessary data (e.g., 50th and 85th percentile speed, roadway characteristics, and crash history). If the segment you are studying is a new route, the system will not require this data, but it is recommended that the statutory speed be posted on new routes until such time that reliable data on operating speed, crashes, and other factors can be collected.Īfter entering all project information you will have the opportunity to save the recommendation report.

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