Intermittent nighttime lane closures will continue on MoPac through the end of July to allow workers to drill into the soil surrounding the roadway to collect samples.

The work is being done in preparation of the Central Texas Regional Mobility Authority beginning construction on the MoPac Improvement Project this fall.

"We're certain there will be construction in the fall," said Steve Pustelnyk, director of community relations for the MoPac project.

Pustelnyk said crews are using a corkscrew-like drill to bore into the ground to a depth of about 5 feet to measure the soil, testing for parameters such as density.

When construction begins this fall, crews likely will start with utility relocation and building the sound walls, he said.

The MoPac project will add one express toll lane in each direction on MoPac from Parmer Lane to Lady Bird Lake. The Mobility Authority, which builds and operates toll roads in Central Texas, is overseeing the project.

Heather Reavey, vice president for HNTB—an architecture, construction, engineering and planning services firm contracted by the Mobility Authority—said that since the contract with design-build firm CH2M Hill has been executed for the MoPac project, the design phase has begun. She said CH2M Hill's proposal included some design modifications that will require CH2M Hill to review the project's environmental documents.

The design modifications include the connection from the toll lanes into downtown, she said. CH2M Hill is proposing to use underpasses and go under the existing main lanes instead of going over them. The firm needs to have 30 percent of the design completed before construction can begin.

Mobility Authority Executive Director Mike Heiligenstein said the design modification that CH2M Hill is looking at for the connection into downtown has already been reviewed.