About 100 people on bicycles, dirt bikes, and motorized scooters went on the Zakim Bridge and into the O’Neill Tunnel on Sunday, leaving the highway at the Government Center exit, police said.

Adam Harrison, 22, of Winthrop, tells Boston 25 News he was riding his pedal bike innocently and never rode on the highway or in the tunnel. He simply caught up with the group in the Seaport District and was in the back of the pack when he was arrested,