A 79-year-old motorist died on Louisiana 25 north of Covington after an 18-wheeler slammed into his pickup's driver side door Tuesday afternoon, according to authorities.

William J. Guarino, of Covington, died at the scene of the 2:30 p.m. collision. Michael Gordon, the 49-year-old driver of the 18-wheeler, was taken to St. Tammany Hospital, where doctors treated him for moderate injuries, according to a statement by Louisiana State Police spokesman Louis Calato.

The crash happened after Guarino, driving a 2006 GMC pickup westbound on River Road, pulled out in front of Gordon as he drove a Freightliner 18-wheeler northbound Louisiana 25. Guarino, who authorities say didn't yield, was trying to enter the southbound lanes of Louisiana 25.

At that point, Gordon, who was wearing his seat belt, was unable to avoid striking the extended cab pickup's driver door. The 18-wheeler slammed into the truck, and each vehicle came to rest only after ending up in a ditch on the west side of the road, Calato said.

A St. Tammany Parish coroner's investigator pronounced Guarino dead from injuries sustained in the crash, and paramedics took Gordon to the hospital, Calato said.

The emergency response backed up traffic on Louisiana 25 nearly two miles in each direction.

State police don't suspect alcohol was responsible in the crash, Calato said. Regardless, troopers submitted blood from each driver to a crime lab for analysis.