The speed limit on much of Minnesota Highway 61 between the Lafayette Tunnel and the Canadian border was raised from 55 to 60 miles per hour last week.
Crews started changing signs on Nov. 12, said Pippi Mayfield, public engagement and communications director for the Minnesota Department of Transportation.
The 55 mph speed limit will remain in place south of the tunnel, which is about eight miles north of Two Harbors.
The 55 mph speed limit will also remain in place between Schroeder and Temperance River State Park, Temperance River State Park and Tofte and on the Grand Portage Reservation between Mineral Center Road and Store Road, according to MnDOT.
In 2014, the state legislature mandated that MnDOT study all two-lane roadways with a 55 mph speed limit to determine if speed limits could be safely increased to 60 mph.
The traffic and engineering study looked at past crash rates, physical attributes of the highways and an analysis of current driving speeds, according to a news release.
In total, MnDOT decided to increase the speed limit on 5,240 of 7,000 state highway miles looked at in the five-year study.