If you were planning to take Interstate 35 through North Austin this weekend, don't.

The Texas Department of Transportation says northbound and southbound traffic between Rundberg Lane and U.S Hwy 290 will be reduced to just two lanes each – from 9 p.m. Friday all the way until 5 a.m. Monday.

The southbound I-35 main lanes will close and become a work zone over the weekend, as crews partially demolish the St. Johns Avenue bridge over the interstate and install beams for a flyover. Two lanes of southbound traffic will be shifted onto what is normally the left two northbound lanes.

TxDOT says new striping and barriers will help guide drivers through the reroute. If you're having trouble visualizing it, here's a diagram:

Diann Hodges, a TxDOT spokesperson, says drivers should expect major delays if they decide to take I-35 this weekend. If you have another option for getting around Austin, she suggests you take it.

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"Typically when we take down a bridge and set beams, we divert the traffic to the frontage roads," Hodges said. "It's just not an option in this case."

Starting Thursday at 9 p.m., traffic on the St. Johns Avenue bridge will close until Aug. 30 as it's demolished and rebuilt to accommodate improvements to I-35, the transportation department said.

It's the first of three closures on I-35 planned in June for this project. You can learn more at My35Construction.org.