Beginning Oct. 15, a lower wintertime speed limit will be imposed on a stretch of I-80 in Wyoming.

The 65 mph speed limit will be posted and enforced for six months in an effort to reduce crashes on the 52-mile section of Interstate 80 between the Peterson Interchange 22 miles east of Rawlins and the Quealy Dome Interchange 20 miles west of Laramie.

In addition, by late November, the Wyoming Department of Transportation expects to have variable speed limits signs installed on part of the section to allow the speed limit to be dropped to as low as 35 mph when needed due to road or weather conditions.

The new limit is being set because the highway section is prone to unpredictable and extreme weather. "High winds, icy roads and blowing snow have contributed to the challenges faced by motorists," explains Wyoming Highway Patrol Col. Sam Powell. "The weather is extremely unpredictable, and you can have great visibility and dry roads one minute and near zero visibility and solid ice the next."

The 10-mph speed reduction will give drivers additional time to react to situations that unfold very rapidly in front of them.

The seasonal speed limit also will set the stage for further speed limit reductions using the variable signs based on a case-by-case evaluation of road and weather conditions, officials say.

The highway will return to a 75-mph speed limit on April 15.

WYDOT's analysis of crash and speed data indicates about three-quarters of all crashes on I-80 during the past decade occurred during the winter months, and unsafe speed was a factor in 71 percent of them.

Ten sensors have been installed on the highway section to gauge the speed of traffic, and additional weather and visibility sensors are planned to provide information to help decide what the safe speed limit for the conditions is.

The University of Wyoming is working with WYDOT to study the effectiveness of the system, and if the pilot project proves effective in reducing crashes, other I-80 sections have been identified as candidates for variable speed limits in the future.