Drivers could be traveling 70 mph on some Wyoming highways by the end of the month under a bill Gov. Matt Mead signed into law Tuesday.

The Wyoming Department of Transportation expects the new limits to be in effect for roughly 1,500 miles of highway by the end of April, and another 1,000 miles of highway by the end of May. Work is slated to continue through the summer.

Wyoming Department of Transportation spokesman Dave Kingham says the change will cost about $1.5 million in total, including more than just new speed limit signs.

“In some areas we’re going to have to put additional curve warning signs and change the striping for the passing and no-passing zones to reflect the higher speeds,” says Kingham.

Kingham emphasizes that a highway’s speed limit will only increase when new signs are in place.

“Drivers are required to adhere to the speed limit posted on any highway section,” says Wyoming Highway Patrol Col. Kebin Haller.

Some sections of US 85 between Cheyenne and Newcastle, US 130 from Walcott Junction to Saratoga, and WYO 120 from 18 miles north of Cody to the Montana border already allow drivers to travel 70 mph.

“We’ll look at the roads and driving behaviors to ensure there is no significant increase in crashes,” says WYDOT Director Bill Panos. “If we find there has been a significant increase, we will take the actions necessary to protect the safety of the driving public.”

The speed limit increase will require 900 new speed limit signs, according to State Traffic Engineer Joel Meena. The department says materials were ordered in early March, and the new signs should be finished by the end of the month.