| State: | UT |
| Type: | SR |
| Route: | 145 |
| Alternate Name: | Pioneer Crossing American Fork Main Street |
| Section: | 120 |
| Map Custom: | yes |
| Map Notes: | SR-145 highlighted in red |
| Length Mi: | 6.862 |
| Length Round: | 3 |
| Length Ref: | [1] |
| Established: | 1978[2] |
| Direction A: | West |
| Terminus A: | in Saratoga Springs |
| Junction: | in Saratoga Springs in American Fork |
| Direction B: | East |
| Terminus B: | in American Fork |
| Previous Type: | SR |
| Previous Route: | 144 |
| Next Type: | SR |
| Next Route: | 147 |
State Route 145 (SR-145), a majority of which is also known as Pioneer Crossing, is a 6.862-longNaN-long west - east thoroughfare completely within Utah County in northern Utah that cuts through Saratoga Springs, Lehi, American Fork, and portions of unincorporated Utah County. The portion between Interstate 15 (I-15) and U.S. Route 89 (US-89) has been under state jurisdiction since 1978, while the roadway between SR-68 and I-15 (the section named Pioneer Crossing) opened in 2010. The road (and Pioneer Crossing name) were extended from SR-68 to SR-73 in 2014. The road runs mostly parallel to and south of SR-73, which also connects to SR-68 and I-15. The original portion of the route between I-15 (including the interchange) and US-89 is designated as Main Street in American Fork's street grid.
Commencing from the route's western terminus in northern Saratoga Springs, SR-145 heads southeast as Pioneer Crossing with two lanes in each direction, divided by a center turn lane. The road turns east just prior to the intersection with SR-68, then crosses over the Jordan River. The route then takes a brief northeasterly turn before returning due east, and passing through a rural area of western Utah County before entering a stretch of development past 2300 West. The highway turns southeast to avoid development before again turning northeast and east. The road gains a third lane in each direction past 300 East (on Lehi's grid) then becomes American Fork Main Street just prior to where it meets I-15 at a diverging diamond interchange (DDI). The road continues east for about a half-mile and ends at an intersection with State Street (US-89).[3]
The entire route is included in the National Highway System.[4]
State maintenance of Main Street in American Fork (from I-15 to US-89) was established in May 1978, the state legislature approving that the following year. By 2003, a concept of a connector between Redwood Road (SR-68) and I-15 was presented in an environmental impact study for the Mountain View Corridor. After a separate study was completed in 2008, plans to construct the connector were set in place. As part of a project to reconstruct over twenty miles of I-15 through Utah County, the present interchange at Main Street was set to be rebuilt as a diverging diamond interchange (DDI). Construction began in early 2009, with the road opening to traffic between US-89 and SR-68 on August 23, 2010.[5] [6] The DDI was the second to be opened in the United States, the first being in Missouri.[7] In June 2014, construction began to extend Pioneer Crossing northwest of SR-68 to SR-73.[8] The extension was completed on November 26, 2014.[9]