BAY POINT -- A 44-year-old Concord man died Wednesday afternoon when he drove his motorcycle into the back of a box truck on Highway 4, a California Highway Patrol spokesman said.

The wreck occurred in the eastbound direction just before the San Marco Boulevard exit at about 1:25 p.m. The CHP earlier reported the wreck occurred closer to Bailey Road because it took nearly half a mile for the truck driver to pull over because other cars were in front of him, CHP spokesman John Franzen said.

The far right three lanes were closed at 1:47 p.m. and remained that way until just after 3 p.m., when the CHP began reopening them.

An early CHP investigation indicated that the motorcycle driver was moving at a fast speed when he tried to move from the No. 2 lane to the No. 4 lane, only to collide with the back of the truck, Franzen said. Police did not identify the man, pending notification of his family.

The truck driver, who was working for Bateman Senior Meals, a meal delivery service, was not injured but was badly shaken, Franzen said. The motorcycle driver appeared to throw up his hands right before impact and became impaled in the back of the truck, Franzen said.

"He was just driving when he felt this big old bump," said Michael Howe, the owner of Bateman Senior Meals. "He pulled over, and several other people were already there. That's when (the driver) saw what had happened."

The CHP is investigating whether drugs or alcohol were a factor in the collision, Franzen said. The truck driver will not be arrested, he said.

Follow Daniel M. Jimenez at Twitter.com/dmjreports, and follow Rick Hurd at Twitter.com/3rderh.