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Wyoming highways

Eastbound trucks jockey for room on Interstate 80 in Cheyenne, Wyo., in 2011.

CASPER, Wyo. — A Wyoming state law increasing speeds to 80 mph will begin on some sections of interstates Tuesday.

In March, the Wyoming Legislature passed a bill allowing the 80 mph speeds when it’s safe, as determined by Wyoming Department of Transportation engineering and traffic investigations. The law goes into effect Tuesday.

WYDOT crews will begin installing signs on nearly 500 miles of rural interstates from Tuesday to until probably the beginning of the Fourth of July holiday weekend, according to a WYDOT statement.

During the transition, the 75 mph speed limit will remain the speed limit until 80 mph signs are in place in the eight sections that will increase top speeds.

Speed laws will be enforced, Wyoming Highway Patrol Col. John Butler said.

The highway patrol has an internal policy that gives officers discretion about whether to issue a warning or ticket when the driver is speeding up to 5 miles over the limit.

Officers must write a ticket for speeding over 5 miles of the limit, Butler said.

That policy won’t change with the new limit, he said.

“If exceeding 80 mph, whatever course of action the officer takes, we need to make sure it gets people back to 80 mph,” he said.

Bruce McCormack, chairman of the Wyoming Transportation Commission, said the changes are common-sense improvements.

"But it's also for all drivers to adopt an extra measure of caution in traveling at these higher speeds so that this change does not come at the cost of more traffic crashes, injuries and fatalities,” he said in the statement.

While groups such as the National Motorists Association say 80 mph limits cut down on accidents because traffic more frequently travels at the same speed, a 2009 report in the American Journal of Public Health found that more than 12,500 deaths were attributable to increases in speed limits on all kinds of roads.

Wyoming joins Utah and Texas as states that have speed limits above 75 mph on rural highways. Idaho is also preparing to implement an 80 mph speed limit on some of its interstates, the statement said.

Two additional sections of freeway may get 80 mph speed limits: 46 miles of I-80 from west of Rawlins to just west of Walcott Junction, and 17 miles of I-90 from east of Sundance to the South Dakota state line, said Del McOmie, WYDOT’s chief engineer.

To determine which sections of freeway were eligible for 80 mph, WYDOT obtained a history of crashes, mile by mile, McOmie said.

It considered urban areas that tend to have more traffic and interchanges with traffic merging in and out of lanes, accelerating and decelerating.

It analyzed terrain, curvatures in the road, traffic volumes, wildlife crossings and the mix of traffic, such as cars and commercial trucks, McOmie said.

Wyoming has 914 miles of interstate highway. Slightly less than 500 miles of roadway will have the new speed, he said.

Some sections will have additional signs to remind drivers to adjust their speeds from 80 mph to 75 mph, McOmie said.

“Not all of the interstate’s moving to 80 mph,” he said. “They’re going to have to pay attention to signs.”

James Goossen