Rain and heavy traffic contributed to a series of wrecks involving about 80 cars along a highway during Wednesday morning's rush hour, injuring 34 people, one seriously, officials said.

Lt. Everett Clendenin of the state Highway Patrol said there were 44 collisions along a five-mile stretch of Interstate 40. The wrecks snarled traffic about 40 miles west of Raleigh when the interstate was closed. The road had reopened by 11:15 a.m., troopers reported.

The first accident happened at about 7:30 a.m., when a man driving a minivan struck a stopped Greyhound bus in the rear. The van's driver was transported by helicopter to a hospital, Clendenin said. His condition was unknown, Clendenin said.

The passengers on the bus were traveling from Richmond, Va., to Charlotte.