If cyclists want to share the busy roads, we should employ some of the simple things that can make a critical difference to our safety. We have more to lose and its not enough to be right, we should avoid being in the potentially wrong place as far as possible!
I have found a rear-view mirror critical for cycling in busy roads. It offers me the ability to constantly monitor my environment and strategise my approach at critical areas such as congested, narrow roads, bus bays, traffic junctions, slip roads leading to my lane etc.
Often, on narrow roads, the cyclist behind me might yell out a warning, "truck approaching," usually after they were alerted by the sound of the truck and a quick look back to check. I am always struck by how much earlier my rear-view mirror had detected the truck, well before we could hear it.
It also helps me decide when to start filtering when I need to switch lanes. I use the mirror to look for a gap (an earlier traffic light may create a gap in traffic), and when one approaches, I swivel my head for an exact fix before making my move. This minimises traffic disruption and I find myself switching lanes in relative safety.
The area immediately before and after a bus stop is a hazardous zone to the left-lane bound cyclist. This hazard is amplified by heavy traffic and is potentially hazardous on narrow, busy roads which leave bus drivers with little leeway.
The critical zone is the corner of bus bays just before a bus swings in. This critical zone increases significantly with the bus' speed - although in actual fact, bus captains are supposed to slow down.
I try to eliminate interaction in this area well in advance with the help of my rear-view mirror. Depending on distance, speed and other traffic, I may slow down and get behind a bus well before we reach the bus-stop, or accelerate ahead, and take the middle of the left-most lane in front of the bus, before it turns into the bus bay.
By planning ahead, reducing the number of critical situations and expecting the environment to change at any time. I am able to react much faster to any given situation, enjoy a safer ride, and reduce or even eliminate disruption to traffic.
My observations of local cyclists at mass events or on the road suggests few seem to use a rear-view mirror, although these are easily available in bike shops. I do feel rear-view mirrors should be one of the minimum requirements a cyclists should bear, along with a helmet, rear and front lights, if we want to share the road.