I very much agree with your last statement; if you are undertaking a bus or other large vehicle you probably shouldn't be cycling at all. Of course there are exceptions to this.

Although lighting is a very important factor of being safe when cycling on the road, being aware of traffic and the law of the road is far more beneficial. I have cycled around London for years, usually with no lights at all and perhaps it is luck, but I have never had an accident.

You need a strong position in the road and decisive action that allows other road users to see your intentions - just act as if you were a car.