Harris County Toll Road Authority will switch southbound traffic on Hwy. 249 to the newly constructed frontage road beginning Wednesday morning, HCTRA Program Construction Manager Karen McKinnon said. HCTRA crews will begin shifting traffic at about 10 p.m. Tuesday, May 1, and the frontage lanes will open at about 5 a.m. Wednesday, May 2, McKinnon said. Lanes will be closed overnight, but drivers should not be substantially affected, she said. "It really shouldn't affect traffic. Traffic is pretty light there Tuesday night," McKinnon said. "They're going to shift the southbound lanes down to the new frontage road. It'll be an overnight closure." The traffic pattern change affects drivers on the existing main lanes of Hwy. 249 between Spring Creek and just north of FM 2920, where HCTRA is working to extend the tolled portion of Hwy. 249 to the Harris-Montgomery county line. New traffic signals have been added as well as a temporary transition to the southbound lanes to facilitate the traffic switch, McKinnon said. Shifting traffic to the frontage road allows crews to begin work to reconstruct the existing southbound main lanes. "In about a month and a half, we'll do the same thing to the northbound side,"McKinnon said. "And then they'll be ready to start the middle work. That work will be going on until late 2019 when we're actually done with the main lanes." HCTRA's portion of the Hwy. 249 extension project is slated to be complete in December 2019 when the new, tolled main lanes will open alongside of the frontage lanes.