Department of Transportation

Speed Monitoring Program

The U.S. Congress enacted the National Maximum Speed Law (NMSL) in 1974 as a temporary response to a severe fuel shortage. The law capped maximum speed limits at 55 mph (89 km/h) on all roads and became a prerequisite for receiving Federal funding for highway projects. Congress repealed the NMSL in 1995, fully returning speed limit setting authority to the states.

Although speed monitoring was no longer mandatory, NJDOT continue to monitor roadway speeds at all Weigh-in-Motion (WIM) and select Traffic Volume System (TVS) sites. See WIM and TVS Map for the locations.

The following speed report is calculated using Weekday Data (Monday thru Friday) from WIM sites and is summarized each month as follows:

Monthly Speed Data:

Average speed or mean speed is the sum of all individual speed measurements divided by the total number of vehicles.

Median speed - the speed at or below 50 percent of vehicles travel.

85th percentile speed - the speeds at or below 85% of all vehicles are observed to travel under free flowing conditions.

NOTE: The last three columns of the table in the PDF files reflect the percentage of vehicles exceeding 65 miles per hour, 70 mph and 75 mph.

Last updated date: February 12, 2024 3:33 PM