PROVO — If you plan to use mapping services like Mapquest to find your way around Utah this summer, you may want to look twice.

Two weeks ago, from Mona to the Idaho border, UDOT began changing the numbers on the exit signs along I-15, which has caused confusion for a few drivers in unfamiliar territory.

The exit numbers, which are determined by the mile marker where the exit is located, are being changed to reflect a recently completed mile-marker adjustment.

The milepost markers were inaccurate because of various reference system adjustments as highways were built. Utah County signs have already been replaced; UDOT is working on signs in Salt Lake County and farther north.

UDOT spokesman Nile Easton said the old markers and signs were causing problems — not just for UDOT, but also for emergency personnel and police.

"The inaccuracies of the system were confusing to a lot of people. They were confusing for emergency responders, it was confusing for us when we were doing projects and it was confusing to the public," he said. "A lot of people didn't notice it, necessarily, but when your system is off 3 to 4 miles, it starts to cause problems."

Easton said planners anticipated short-term confusion, but the long-term benefits will be worth the problems caused.

"We knew the growing pains of changing the system were going to be difficult, but the gain is, we'll now have a system that is accurate," he said. "So when you say milepost 287, it will be 287 miles, whereas in the past, it could be a range of 3 to 5 miles."

Pizza delivery worker Nik Martinsen said he hadn't noticed the exit number changes — but he really only drives between two I-15 exits.

Recent Brigham Young University graduate Alanna Nelson said she hadn't noticed the changes either but heard about them from a friend giving directions to a bridal shower.

"I go by the name of the town more than the number, but she was freaked out because she didn't know which exit number to give people," Nelson said.

Easton said since many residents refer to exits by name rather than number, the change hasn't yet caused major disruption.

But visitors may need to double-check their directions.

"There are some in rural parts of the state that just have the number, but in the urban part, people know the 3300 South exit, they don't go by the number," he said. "The people out-of-town, who are hitting Mapquest, that's probably our big problem right now, and we're working with Mapquest to see they get the latest information. But it takes some work on their end to get the changes in."

UDOT officials have also been working with members of the hotel and service industries to ensure a smooth transition.

"There's no easy way to do this, and we knew that going in, so we created a public-involvement group that keeps the hotel industry, the sign industry, all the mapping companies updated constantly," Easton said.

The exit signs, as well as services signs, will not be replaced; instead a sticker will be added to any sign referencing the exit. Easton said the project is moving faster than expected and could be complete by September.

A free map of the updated exit numbers has been available since March.

For a copy of the map and more information on the project, go to and look under "Popular Topics."

E-mail: [email protected]