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.
In most cases, .08, some places .05. In DC, your BAC can be 0, but if, when they ask you at 10 at night if you have been drinking, you say you only had a glass of wine at noon, you can still be charged with a DUI, and hundreds of people have not only been charged but convicted. If you're over age, you can drive IF you're under the legal limit. In Massachusetts (where I live), it's .08. That's like ONE drink for most people, and I'm 5'2, so that might even put me over. I would never, EVER say that it's ok to drive if you've been drinking.