Delaware State Police investigated a crash on Del. Route 1 southbound that involved a tractor trailer north of the Kent County line Monday afternoon.

A New Castle man was killed in a crash on Route 1 in Smyrna Monday.

An investigation by the Crash Reconstruction Unit revealed that a 2010 Ford F250 with a camper attached was legally parked on the right shoulder of Route 1 southbound, south of the Paddock Road overpass. The vehicle was occupied by Anthony J. Zeigler, 74, who was properly restrained, and Kyong S. Zeigler, 71, who was entering the passenger side of the vehicle as the collision occurred. The Zeiglers are from Fleetwood, Pa.

A 2004 Hino panel truck, driven by Goldwire Jackson, 63, of Wilmington, was traveling south on Route 1, in the right lane. Michael G. Stigler, 37, of New Castle, was in the truck's passenger seat. The truck, for an unknown reason, drifted onto the shoulder, and struck the rear of the parked camper. The truck then rotated clockwise and onto its driver's side as it traveled into the grassy area on the west side of the roadway, where it came to rest.

Jackson, who was not properly restrained, was transported to Christiana Hospital by Delaware State Police helicopter, where he was treated for non life-threatening injuries, and released.

Stigler, who was properly restrained, died at the scene.

Both of the Zeiglers were uninjured.

Route 1 southbound at exit 119 was closed for approximately five and a half hours as troopers investigated and cleared the crash.

The crash remains under investigation. No charges have been filed.