Originally Posted by
Slaninar
Looking over one's shoulder before maneuvering is a must. It's called "a lifesaver" in motorcycling. In a car you could damage a car, on a two wheeled vehicle you can get seriously injured. Always look over one's shoulder just in case - checking blind spots. Mirror just makes it possible to do just one look over a shoulder - once you see in the mirror it is clear. Instead of looking many times until it is clear (without a mirror). But having a mirror should never exclude checking over one's shoulder before turning. It can be a costly one second "saved".
Absolutely. Quoted in entirety for emphasis. This should really be the last word. Is there another field of human endeavor where so much misinformation is promulgated by the ignorant as sage wisdom and competes head to head with reality in an ongoing existential stalemate? It would simply be head scratching if it weren't for the fact that cyclists are out there dying for their ignorance, and refusal to adopt safer practices in light of new information.