The Texas Department of Transportation will close portions of I-35 in North Austin throughout the week as crews inch closer to opening portions of a yearslong project.

Main lanes on US 183 will be closed on March 22-24 as construction crews install a guardrail for the upcoming southbound I-35 to southbound US 183 flyover, the state agency announced the morning of March 22.

Starting March 22, closures on the US 183 main lanes will begin at 11 p.m. every night and last through 5 a.m. the following morning, weather permitting.

Drivers on northbound US 183 are instructed to use the I-35 at Lamar Boulevard exit and follow the frontage road to get back on the northbound US 183 main lanes after Georgian Drive. Traffic on southbound US 183 will detour to the frontage road at the I-35 N. to Waco exit and get back on the US 183 main lanes at the Cameron Road entrance ramp.

Further closures at the southbound to northbound I-35 U-turn at US 183 will begin at 9 p.m. and last through 5 a.m. through March 24.

Southbound I-35 frontage road traffic will be directed to proceed through the signals at the I-35 at US 183 interchange to access the northbound frontage road.

TxDOT is on track to open the new flyovers from I-35 southbound to both directions on US 183 sometime in April, according to TxDOT Public Information Officer Brad Wheelis.

The full project, which includes a reconstruction of the existing northbound I-35 to northbound US 183 flyover, is expected to open by the end of 2021.