NEW YORK CITY (WABC) -- Police have crushed about 70 confiscated motorcycles to send a message to what New York City's top cop calls "nitwits" who illegally ride the vehicles.Commissioner William Bratton said the department has been cracking down on unlicensed drivers who operate ATVs, mini-bikes and motorcycles without helmets. So far this year, more than 679 bikes have been confiscated and dozens of drivers arrested on such charges as reckless endangerment.On Tuesday along the Brooklyn waterfront, bulldozers crawled back and forth over the bikes, flattening them with metallic clatters and creaks."We want to send out a strong message to the nitwits and knuckleheads who insist on operating these illegal vehicles on the streets," Bratton said. Eyewitness News was given an exclusive firsthand look as teams of officers swarmed the streets in the 44th Precinct, confiscating a truck load of illegal, unlicensed and unregistered motorcycles. Inspector Brian Mullen is commanding officer of the 44th Precinct, and he revealed during our exclusive ride-along the difficult efforts to stop the bikers."We do not pursue," he said. "What we try to do is tactically deploy to areas where we can block them."Hundreds of motorcycles thought to have been stolen and in poor working condition pose a threat, police said, especially in the hands of roving bands of riders driving recklessly."Riding on sidewalks, disregarding traffic signals with no regard to pedestrians, other motorists," Mullen said.With the bikes now piled up at the Erie Basin tow pound, NYPD officials wanted to make a statement with the crushing serving as a message to riders."One hundred and four arrests for reckless endangerment, and in each and every case, these individuals placed our citizens of this city in great danger," Chief of Patrol Carlos Gomez said. "By continuing these operations, we look to deter, prevent and certainly minimize those in the future."