The Maine Turnpike was opened in 1947 as the first superhighway in the United States created after World War II. Speed Limit History on the Maine TurnpikeAccording to Wikipedia, when the Maine Turnpike opened in 1947, it had a speed limit of 60 mph and only ran from Kittery to Portland. In the early 70s, it was raised to 70 mph, but it didn't last long. The Maine Turnpike Authority does not release data on the number of accidents on the Turnpike. What they do release is the number of calls received at the Maine Turnpike Authority's Traffic Management & Communications Center, which keeps data from 2016 2016 to 2022.