LIVERMORE -- A Modesto boy was stabbed during a melee over the weekend between a group of teens and a motorcyclist angry with them for crossing a major Livermore street, police said.

The hot tempers flashed Saturday night at about 6:50 p.m. between a group of boys on a bus trip returning to Modesto from a college fair in Oakland, said Livermore police Officer Traci Rebiejo.

The bus, carrying 44 teens, stopped at an In N Out Burger on North Livermore Avenue. Approximately 20 of them then decided they'd rather eat from the Jack in the Box and crossed the road, a move that sparked the fight with the motorcyclist, Rebiejo said.

"He says they nearly caused him to crash," Rebiejo said. "So he goes into Jack in the Box and confronts them."

The teens surrounded the motorcyclist and witnesses told police they attacked him, Rebiejo said. The motorcyclist responded by pulling out a knife and swinging it around, stabbing the Modesto teenager in the arm, Rebiejo said.

The motorcyclist was treated for a bloody face and a broken nose, and the teen was treated for a wound to his arm, Rebiejo said. Nobody else was injured, and no arrests have been made by police.

Police admonished the kids for making the decision to cross one of Livermore's busiest roads.

"Technically, they were jaywalking," Rebiejo said. "I wouldn't run across that road. Way too dangerous."

Contact Rick Hurd at rhurd@bayareanewsgroup.com and follow him at Twitter.com/3rdERH.