Drivers can expect delays on I-35 south of Williams Drive Thursday night as work crews construct parts of a traffic barrier rail.

From 8 p.m. June 4 to 5 a.m. June 5, the number of southbound highway lanes will be reduced from three to one while the county’s contractor Hunter Industries places concrete for the rail at the columns of the new southbound to northbound turnaround bridge over I-35. Only the southbound lanes of the highway will be impacted.

Crews will close off the entrance ramp between W. University Avenue and Leander Road, and vehicles will be required to continue south and enter southbound I-35. The closure will end just past Leander Road.

Along with police officers on hand, electronic message boards will be set up to provide advance notifications to the public on the lane closure, according to a county press release.