For 48 hours there has been an invasion or dirt and mortorbikes, operating at ear splitting levels, drag racing on Chapel and College Streets. They seem to drag race west on Chapel, into West Rock, head to East Rock and repeat. The bikes are illegally altered to make the mufflers illegally loud. They also rev their engines, eave in and out of traffic, and block pedestrian crossings. This is in full view of the police, who do nothing about them! It is treacherous and a noise pollution issue!