Motorcycle gangs called bosozoku are the bane of Japanese police.
These irreverent youths race recklessly through the streets with an unmuffled roar that disturbs the country's vaunted peace and quiet. Other departments try to lure the cyclists to a roadblock and drop a net on them. The strategy is to get the motorcyclists to drive down one of several routes on which police have planted a series of MAD metallic boxes, which lie flat and look like metal plates on the pavement. As a motorcycle races over a plate, the lid flips up after the front wheel has passed. That exposes an adhesive, which sticks to the motorcycle's rear tire.