Has the Speed Limit Increase from 55 To 65 MPH Had an Impact On Motor Vehicle Accidents?
In an effort to increase fuel efficiency nationwide, the U.S. Congress repealed the National Maximum Speed Limit of 55 MPH in 1995, and gave states the responsibility of implementing a 65 MPH limit. At the time, New Jersey chose not to implement it since the mandate focused on a type of roadway the state did not have many of — rural interstates.
However, in late 1997, the State Legislature acted to raise the speed limit on interstate highways, as well as the Turnpike, Garden State Parkway and Atlantic City Expressway. When the law passed in 1998, roughly 400 miles of New Jersey roadway were chosen for the speed limit increase, and an 18-month safety study was initiated. This 18-month study hoped to assess the impact of the speed limit increase on several issues:
- Public safety
- Accident rates
- Collision-related fatalities
- Average driving speeds
- Air quality and noise levels
- Administrative costs
The study found that average-driving speeds increased only 1 to 2 MPH on highways and about 3 to 4 MPH on the turnpike, so the difference was relatively insignificant compared to the 18 months prior to the speed limit increase. Fatalities actually decreased by 9.6 percent and fatal accidents decreased 7.9 percent in the 65 MPH zones.
While accidents with injuries increased by 9.4 percent and the total number of reported accidents increased by 18.3 percent, the NJ Department of Transportation determined the data was inconclusive. This is because accident rates fluctuated by as much as 12 percent annually between 1984 and 1996. So, NJDOT could not be certain that the increase in accident rate was due to the 65 MPH speed limit or normal fluctuations in accident rates over time. The study also did not detect any appreciable changes to administrative costs, enforcement or the environment.