Police responded after dozens of teens were spotted and seen on video riding through the O'Neill Tunnel on bicycles, according to Massachusetts State Police.
Police said about 30 kids on bicycles entered the tunnel from Leverett Circle around 6:30 p.m. Saturday.
Video shows the teens riding alongside cars in the tunnel Saturday night, and the Massachusetts Department of Transportation said they were also spotted on the Zakim Bridge.
William Dyer and his wife were heading home from Cambridge to Hanover Saturday evening when his truck was surrounded by the bikes.
"I see a kid riding a wheelie on the highway, and I thought they were making a movie, so I got all excited," Dyer said. "I thought we were going to be in the movies because they are making so many movies in Boston now."
But, when Dyer didn't see any film crews, he began to worry.
"That's when I put my hazards on, and I stayed behind them so no one would get hit because we were going around corners and people were beeping the horn," Dyer said. "I was afraid someone was going to get hurt, it was dangerous."
Dyer said the teens could have easily been injured.
"People were coming around 60 miles per hour then locking up the brakes," Dyer said. "I just didn't want the kids to get hurt, some of them looked like they were 14 years old."
Troopers responded to the tunnel and police said they forced them out at South Station.
Police said once the group was out of the tunnel, they dispersed and fled, and police did not pursue.
Cox Media Group