OGDEN -- One of the biggest projects in Interstate 15's history will begin two years from now in the Top of Utah.
In an effort to make more room on I-15, particularly for carpoolers, the Utah Department of Transportation is conducting an environmental study on a project that will add express lanes on I-15 from I-215 in North Salt Lake to U.S. 89 in Farmington, and from Hill Field Road in Layton to the junction with I-84 in Riverdale.
The new lanes would total 21 miles on both the north and south sides of the freeway.
When the project is finished, it will connect approximately 80 miles of Express Lanes from Spanish Fork to Ogden.
UDOT project manager Brett Slater said concept designs for the road will be finalized by the end of the summer and a series of public meetings will be held in October.
Final environmental clearance is expected by early spring 2013.
Slater said construction would likely begin in summer 2014.
UDOT spokeswoman Mindy Nelson said there is not yet a definitive cost for the project, but the state has already budgeted $86 million for it.
Express lanes, designed to promote carpooling, are free to vehicles with two or more occupants, but solo drivers who want to use the express lanes can purchase an electronic transponder that tracks their use of the lanes.
Electronic overhead signs show drivers the cost of entering the lane, and an online account is debited as they use the lane. Rates are adjusted in real time based on how much traffic is in the lanes.