Louisiana State Police and the U.S. Coast Guard are investigating a hit-and-run crash on the Hale Boggs Memorial Bridge early Thursday.

A Ford F-150 traveling southbound on I-310 around 1 a.m. veered off the road, side-swiping two construction trucks doing overnight maintenance work, WVUE-TV reported. State police said t he crash knocked one worker over the railing into the Mississippi River. Three others sustained minor injuries, authorities said.

The Coast Guard immediately dispatched a rescue helicopter and boat to the area. Search efforts, so far, have turned up no sign of the missing worker. Several miles of the river near Luling is closed to marine traffic while the search continues, official said.

Police are still searching for the driver who fled the scene.