A 47-year-old Vallejo man who was on foot outside his pickup trying to help a stranded motorist on Highway 37 Tuesday afternoon was fatally struck by the driver of a third vehicle, the CHP reported.

Dino Zapantis of Vallejo died at the scene from injuries sustained in the collision, which occurred about 2:58 p.m. in an eastbound lane of Highway 37 east of Mare Island.

Zapantis had tied a strap between his pickup and the stranded vehicle in an attempt to tow it to a safer location, the CHP reported.

The driver of the disabled vehicle was inside Zapantis' truck and Zapantis was outside the pickup's driver door giving her instructions when a white 1995 Honda Accord traveling east on the highway drifted onto the right shoulder and then sideswiped both stationary vehicles before hitting Zapantis, the CHP reported.

The CHP did not detail where the stationary vehicles were in the roadway at the time of the collision.

The driver of the Honda Accord was identified as John Newsome III, 19, of Vallejo.

Alcohol or drugs are not considered to be a factor in the collision, which remains under investigation.

Traffic in both directions was slowed in the area, with eastbound traffic for a time being diverted onto Highway 121.

An initial report by the CHP did not give a make and model for Zapantis' pickup or offer additional information on the stranded vehicle and its driver.

Conditions at the time were described as calm, warm and dry.

In addition to the CHP, firefighters from Vallejo responded to the crash.

Anyone with information was urged to contact Officer Weaver with the Solano division of CHP, 428-2100.

You can reach Staff Writer Brett Wilkison at 521-5295 or brett.wilkison @pressdemocrat.com.