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.
Rear Reflector. 1  Every motor vehicle shall carry on the rear, either as part of the tail lamps or separately, two or more red reflectors. 2  Rear reflectors on a vehicle shall reflect a red color.lear Tail Light Lenses. For clear taillight lenses to be legal, they must consist of the following components: Stop Lamp. 1  All motor vehicles are required to have functioning stop lamp(s), as applicable to the number of stop lamp(s) equipped on the vehicle at the time the vehicle was originally manufactured.