All southbound lanes of Tomball Parkway are shut down near Grant Road after a vehicle hit an overpass and sent concrete debris onto the roadway, according to Harris County Precinct 4 Constable's Office.

Deputies are on scene in the 20500 block assisting with traffic and safety concerns while TxDOT responds to inspect the damage.

Motorists should expect significant delays and use an alternate route until the roadway can be reopened safely.