To the north, the tracks run along the east side of newer sections of the highway from Northland Drive to Braker Lane.

In 1944, the City of Austin Planning Commission (CMAC) proposed that the highway be built in parts of the under-utilized right of way owned by the MoPac Railroad.

It passes through the Circle C Ranch housing development and the Edwards Aquifer and intersects SH 71/US 290 (Ben White Boulevard) and Loop 360 (Capital of Texas Highway).

[10] North of the river, the highway runs parallel to the Balcones Fault and the Missouri-Pacific Railroad (Union Pacific) before it intersects US 183 (Research Boulevard) northwest of downtown.

[11] North of Parmer Lane, Loop 1 continues as a limited-access toll road to the SH 45 North/Loop 1 interchange, spanning 3 miles (4.8 km).

[13] Construction began in 2013, and was originally scheduled for completion in September 2015, but by August 2016, the Central Texas Regional Mobility Authority announced further delays.

In 2013, CTRMA and TxDOT initiated an environmental study to analyze the best options to improve the MoPac intersections at Slaughter Lane and La Crosse Avenue.

On August 10, 2018, the at-grade Slaughter Lane intersection was rerouted to the south as construction began on an overpass bridge on the original alignment.

The full project, including surrounding sound walls and retention ponds, was officially completed on December 16, 2020.

[19][20] In 2013, CTRMA and TxDOT initiated an environmental study of the MoPac corridor from Cesar Chavez Street to Slaughter Lane.