SAN RAMON (CBS SF) — The California Highway Patrol has released a few more details about a deadly crash Saturday morning between a truck and a bicyclist on a road in Contra Costa County, east of San Ramon.

The bicyclist killed in the collision, reported around 9:45 a.m., was part of a group of about 50 to 60 people cycling on eastbound Highland Road, less than a mile west of Carneal Road.

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The collision occurred in an area east of San Ramon and north of Livermore.

The bicyclist was 40-year-old Dublin man, and St. Mary’s High School’s Assistant Principal Herman Shum. He was riding a Specialized bicycle and wearing a helmet, according to the CHP.

The cyclist was traveling at the back of the pack and likely to avoid a crash between at least two bicyclists at the front of the group he crossed over onto the other side of the road, according to the CHP.

Shum, who may have lost control of the bicycle, was then ejected off the bike and landed on the westbound road.

A truck driver, a 56-year-old Livermore man, driving a 2001 Peterbilt truck, saw ahead of him the bicyclists at the front of the pack crash and veered to avoid them. That is when he struck the bicyclist who was in the roadway, along with his bicycle.

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Many cyclists tried to help Shum, but emergency personnel pronounced him dead at the scene.

Another person suffered major injuries and a third bicyclist suffered minor injuries, CHP officials said.

The truck driver was not injured, according to the CHP. He was wearing a seatbelt during the incident.

Highland Road was closed for three hours after the crash.

Drug or alcohol use is not suspected as factors in the crash, according to the CHP.

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