A three-year construction effort to improve mobility along MoPac in Southwest Austin near Slaughter Lane and La Crosse Avenue is now complete.

The Texas Department of Transportation celebrated the end of MoPac Intersection Project construction with a virtual ribbon cutting Dec. 16.

Through the MoPac Intersections Project, TxDOT created new bridges at Slaughter and La Crosse that take local traffic over new MoPac main lanes and allow the continuous flow of traffic on the expressway below.

“This was a major construction project with a unique approach to constructing bridges at existing intersections,” TxDOT Austin District Engineer Tucker Ferguson said.

A diverging diamond intersection design was used at Slaughter, which Ferguson said increases traffic flow and accommodates the large quantity of motorists who travel north toward downtown Austin.

According to Ferguson, the original Slaughter and La Crosse intersections were built in 1992 featuring traffic lights that prevented the continuous flow of MoPac traffic. Since the 1990s, population growth led to increased congestion and accidents at the two intersections, and plans were developed starting in 2013 to address traffic in the area. TxDOT broke ground on the $53.5 million MoPac Intersections Project in January 2018, he said.

“We appreciate the patience of those who live and work here in South Austin,” Ferguson said. “We know construction is tough, and we got through it together. Mobility has already improved through the two new intersections.”

The project was initially expected to be active through 2021 but was completed slightly ahead of schedule. With an estimated 50,000 vehicles traveling on the impacted stretch of MoPac each day, Brian Barth, TxDOT director of project planning and development, said it was important for the department to complete the project sooner rather than later.

State Rep. Vikki Goodwin, D-Austin, said she is one of those 50,000 motorists who commutes on MoPac from Southwest Austin each day.

“I go through that intersection almost on a daily basis, and I've really enjoyed the diverging diamond layout,” she said. “It was a little strange in the beginning, but it seems to provide a much better throughput, much better mobility and seems very safe at the same time.”

The MoPac Intersections Project is the second major transportation effort to open in the area over the past two years. The Central Texas Regional Mobility Authority opened the SH 45 SW toll project in June 2019, which connects to the southern end of MoPac and brings motorists southeast into Hays County.

An effort to add toll lanes to MoPac south of the Colorado River is also still being developed by TxDOT.

“Big picture, the theme is to move traffic and people and goods and commerce through all of our networks together, and many of these projects do work hand in hand,” Ferguson said. “Any of the planning and the design [for South MoPac] will certainly incorporate [the MoPac Intersections Project and SH 45 SW] into the project.”