A Slidell man was killed Thursday after crashing into an 18-wheeler on Interstate 55 in St. John the Baptist Parish, according to Louisiana State Police.

Justin Weaver, 23, was killed about 4:15 p.m. after his vehicle crashed into a 2015 Freightliner driven by Sidney Jarrell, 38, of Denham Springs.

The Freightliner was stopped in the right lane because of traffic congestion from a previous crash. Weaver was driving a 2009 Mazda MZ6 in the left lane approaching the stopped traffic. For reasons still under investigation, Weaver was unable to stop the Mazda in time, swerved to the right, and struck the rear of the Freightliner, State Police said.

Weaver, who had not been wearing a seat belt, was pronounced dead on the scene. The front seat passenger, Samantha Niemeck, 22, was wearing a seat belt and was transported to a hospital with moderate injuries. Jarrell also had a seat belt on and was transported with minor injuries, according to State Police.

Impairment is unknown and toxicology results are pending an autopsy for Weaver. Jarrell voluntarily submitted to a blood test which will be analyzed by the Louisiana State Police Crime Lab. The crash remains under investigation.