Between RM 1826 and Loop 1, the roadway is a divided four-lane facility with a wide median intended to accommodate a future freeway, after which the current lanes would serve as frontage roads.

The other segment is a toll road that forms a backwards C-shape along the boundary of Travis and Williamson County before bending down along the eastern edge of the Austin metropolitan area where it shares its route with SH-130.

Before the 2002 Central Texas Turnpike Project (CTTP), SH 45 existed only as a short section of four-lane, divided highway in southwest Austin.

The CTTP added a toll road that runs east from US 183 near Cedar Park, crosses I-35, bi-secting the La Frontera development, and meets SH 130 near Pflugerville.

The Texas Department of Transportation had originally planned to complete construction of the entire 2002 CTTP in September 2007 but opened some sections of SH 45 North as early as October 31, 2006.

Roughly paralleling Farm to Market Road 1327, it is a four-lane, controlled-access facility that links SH 130 and US 183 to Interstate 35 north of Buda, Texas.

SH 45 Southwest is a 3.6-mile (5.8 km) tollway link between the southern terminus of Loop 1 in the west and Farm to Market Road 1626 to the east.

Opponents claimed the proximity of the southwestern and southeastern sections would create more pressure to connect the two and that, if built, the link would encourage development on or near environmentally sensitive land.

Planning for the western portions of SH 45 to form a complete loop is still very early, although a proposal for possible route has already been offered by the City of Lakeway.

[14] The interchange at I-35 was partially affected by the March 21, 2022 tornado outbreak when a large light pole was ripped off its foundation, the debris resting on the side of a flyover, as seen from photos captured by KXAN-TV.