(Francisco Kjolseth | Tribune file photo) UDOT begins construction of a new interchange at I-15 and Hill Field Road, with a funky ThrU Turn intersection in Layton, as crews clear space next to the freeway for the construction of new bridges as well. Traffic is so heavy in the area now that it takes about 10 minutes to travel a half-mile from Main Street to Layton Hills Mall, with cars often backing onto the freeway.