Mark Wetzel, Deseret News
Variable speed limit signs will soon appear on Interstate 80 through Parleys Canyon. The signs allow UDOT and the Utah Highway Patrol to remotely vary the speed limit depending on weather conditions. The signs are expected to be operational in October.

SALT LAKE CITY — New variable speed limit signs will soon appear on I-80 through Parleys Canyon, and the Utah Department of Transportation hopes they will make driving through the canyon safer — especially during winter.

Car accidents not only destroy lives and property, but they slow traffic on the busy transportation corridor. UDOT and the Utah Highway Patrol coordinated plans and decided to implement signs that would allow them to remotely vary the speed limit depending on weather conditions.

"Driving in canyon settings, such as Parleys Canyon, it's a harsh environment in the wintertime,” said Rob Clayton, UDOT director of traffic management.

Speed detectors located throughout the canyon will record drivers’ average speeds through the area.

"As those speeds drop, we will use that as an indicator that conditions are deteriorating," Clayton said.

UDOT engineers and meteorologists will monitor pavement temperatures, snow accumulation and visibility.

"We will look at the speed data and the weather data to make a decision about what speed is appropriate," Clayton said.

The new variable speed limit signs are currently being tested off the road. When the first winter storm hits Parleys Canyon, the big LED numbers will inform drivers of the new speed limit.

The normal posted speed limit through Parleys Canyon is 65 mph, but Clayton said transportation officials say the speeds could be lowered to 35 mph during winter storms. And the varying speed limits will be enforced, UDOT officials said.

A University of Washington study found that the signs reduced the average vehicle speed by up to 13 percent in Washington and overall safety improved. Clayton called the system's $721,000 price tag affordable, especially if it saves lives.

"We're very hopeful that this will be a good tool to help us manage traffic in bad weather," he said.

UDOT crews will remove all of the old speed limit signs from the mouth of the canyon to Kimball Junction in coming weeks. Fifteen of the new signs will be installed and are expected to be operating by October.

Parleys Canyon was chosen as the pilot location for the signs because of its changing weather conditions during winter months, heavy traffic and existing fiber-optic infrastructure.

UDOT officials said they will evaluate the effectiveness of the signs and decide whether there are other areas they could be installed.