Utah’s top two fastest-growing cities — and their residents — are about to see big changes on a major road.

The Utah Department of Transportation is set to open a new lane in each direction on Pioneer Crossing — also known as State Route 145 — between Lehi and Saratoga Springs in time for Monday morning’s commute.

The added capacity is a part of a larger suite of changes to the road, including “flex lanes” on the thoroughfare due to debut later. During commute times, that means the agency can change the direction of a lane to add more capacity where it’s needed.

“If you’ve ever driven along Pioneer Crossing, you know how needed this project is,” UDOT official Rob Clayton said in a news release. “Opening these lanes will make a noticeable difference and provide a more reliable commute for the thousands of people who rely on this road every day.”

The new lanes will stretch from Riverside Drive to Mill Pond Road. About 55,000 vehicles use Pioneer Crossing each day.

Construction crews largely built the new lanes within the existing envelope of the road. The increased capacity was finished two months ahead of schedule, the agency said, thanks to the winter that wasn’t. The project’s builders also reused some on-site materials, including concrete from demolished parts of the road.

Even though the additional capacity will be drivable on Monday, work on Pioneer Crossing will continue. Next up is the installation of overhead signs that will alert drivers when the flex lane changes are in effect.

Travelers can expect full nighttime closures of short sections of the road while that work is ongoing. Officials are planning for construction on the flex lanes to finish by the end of the year.

Ultimately, the lane switch system will look similar to 5400 South between Redwood Road and Bangerter Highway in Taylorsville.

Once the Pioneer Crossing changes are fully built, the transportation agency expects drivers will save about six minutes on their commutes. Without the project, officials estimated that evening westbound travel on the road would jump from about 19 minutes to 32 minutes, while morning eastbound travel would increase from 14 minutes to 20 minutes by 2037.

With the new lanes and traffic system, officials estimate that the evening drive will tally 15 minutes and the morning ride 13 minutes in 2037.

New lanes in each direction are also coming to the thoroughfare from Mill Pond Road to Interstate 15.

The agency is also set to add another westbound lane from Redwood Road to just west of the intersection with Mountain View Corridor. That section will feature three lanes in each direction once the construction is complete.