People continue to express concern about our decision to raise the speed limit to 70 mph on certain segments of Maine’s interstate highway system.

I understand and appreciate the points brought up by those who do not favor this decision, so I want to explain the process I followed. The decision wasn’t made simply because I thought it was a good idea or because I felt it would be better for motorists to get where they need to go in a shorter time.

In 2013, during the first regular session of the 126th Legislature, L.D. 654, An Act to Raise the Speed Limit on Interstate 295 (PL 2013, Chapter 107) was enacted. This gave me, as commissioner of the Maine Department of Transportation, the authority to either raise the speed limits on select segments of Maine’s interstate system or leave them alone.

The department’s Traffic Engineering Division began to study the issue. They used radar data from 64 variable speed limit signs on the interstate to determine average speed and the 85th percentile speed, which is how fast 85 percent to 90 percent of motorists are traveling. All states use the 85th percentile speed of free-flowing traffic as the basic factor to set speed limits.

Staff also performed test runs on the interstate with members of the Maine State Police. The data showed that most vehicular traffic was traveling in excess of 70 mph for a majority of the day.

So why raise the speed limit? In a word: safety. Traffic moves more safely the closer the operating speed and the posted speed are to one another. The 65 mph posted speed was legislatively mandated, meaning it was up to the Maine Legislature to set speed limits. Had it had been up to the Maine Department of Transportation, the speed limits today are what they would have been all along.


A common misconception is that when the speed limit increases to 70 or 75 mph, drivers will go much faster, speeding up to 80 mph or more. Not true. Approximately 2½ years ago, the speed limit on the interstate north of Old Town was raised to 75 mph. The result has been just 1 mph higher on average than that posted speed.

The simple fact is this: People will travel at the speed at which they are most comfortable.

Another belief is that higher speeds cause more crashes. Statistically speaking, that’s not true. The highest rates of crashes are at 25 mph. Speed alone doesn’t cause crashes; speed differential does. Normally, there is more speed variation at the slower speeds.

The decision to raise the speed limits was not made in a vacuum. We at the Maine DOT talked with the our colleagues at the Maine Turnpike Authority to see what kind of speed limits they had in mind. We consulted with the Bureau of Public Safety and several lieutenants from the Maine State Police. We also discussed the possible speed limit change with several major cities along the route where there are or were perceived problems.

In the more congested parts of the state, such as Portland, Augusta and Waterville, the speed limits did not increase. The close proximity of the on- and off-ramps, along with the volume of traffic, meant it was better to leave the speed limits alone.

No speed is safe, however, when it comes to driver distraction. Texting, phone calling, drinking while driving and other activities take the focus off driving and can lead to serious crashes that result in injuries or deaths. Speed limits are not raised or lowered because of the possibility of distracted driving. Only the driver can control the vehicle’s speed and how well it is operated.


The Maine State Police patrols the interstate and the Maine Turnpike. While they are supportive of the speed limit increase, it is important to remember these speed limits are not set in stone. If, over time, they find the new speed limits are causing problems, we can have a discussion about an adjustment.

Science and engineering tell us drivers will travel at the speed at which they are most comfortable. That’s why I am confident raising the speed limits fits within the Maine Department of Transportation’s mission statement: “To responsibly provide our customers the safest and most reliable transportation system possible, given available resources.”

It is my belief that raising the speed limits is the right thing to do.

David B. Bernhardt is commissioner of the Maine Department of Transportation.

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