A crevasse is a deep crack, or fracture, found in an ice sheet or glacier, as opposed to a crevice that forms in rock. Crevasses form as a result of the movement and resulting stress associated with the shear stress generated when two semi-rigid pieces above a plastic substrate have different rates of movement. The resulting intensity of the shear stress causes a breakage along the faces.
Unfortunately, many cyclists choose to ride their bikes at dark without bicycle head lights or tail lights. This is against the law in most states in the U.S. (Amazingly, Washington, Texas, and others only require a head light and rear reflector.) It is also very dangerous.here are at least two primary reasons for you, a bicycle rider, to use lights at night. 1  First, the front head light illuminates the area in front of you, so you can ride safely, by being able to detect any hazards you approach.
Best Answer: Regulation 33 of the Road Vehicles (construction and Use) Regulations 1986 states that that a two wheeled motorcycle with or without a side car attached are exempt from being required to having mirrors fitted however a motor vehicle first used on or after the 1st of April 1969 must have mirrors.eport Abuse. I have seen bikes with no mirrors but i personally would hate to ride like that, for a start you would have to spin your head right around to check before you overtake or change lane on a dual carriage way... Not safe.