If there is an obstruction ahead of you, be it a stream of vehicles (which will in any case need to move out to overtake the cyclist - big clue there, which you should be able to spot) or a curve in the road, then you should be driving / riding at a speed at which you can
stop in the distance you can see to be clear. This means you do not come round the curve and find yourself unable to slow (indeed stop) simply because there is a cyclist in your path.
If there is a vehicle tailgating you, then you should be looking to increase the available stopping distance (i.e. ride/drive slower) rather than closing in on an unknown situation ahead: Riding faster because you are tailgated is what causes multiple pileups.
The bicycle is a vehicle and progressing at its own vehicular speed. If there is no overtaking lane then the cyclist should be looking for sensible place to let any queue that is forming go past. 'Sensible' in this context includes the cyclist's right to make progress at cycling pace however, and this does not mean diving out of the way of every Clive Toad.
Where there is an overtaking lane, that is the place where overtaking vehicles should be when carrying out that manoevre. It matters not a jot whether they are overtaking a cyclist, a tractor or a granny in a Suzuki Roll-over. In my experience 90+% of drivers manage this quite conveniently; Sure they sometimes have to wait for a gap, but that's just the way it is in crowded road conditions caused by the number of cars (usually with one occupant). I suspect that you are one of those who finds this impossible. I strongly suggest that you look into (as in take) some advanced driving lessons. This is a good site to start with
http://www.advanced-driving.co.uk/
Commuting is not a war zone BTW, it is (or should be) about reasonable people cooperating to allow everyone a safe and predictable journey with their chosen form of transport. Heavy metal dragged by engines increases the risk exponentially and it is incumbent on the drivers of these vehicles to drive safely around
all more vulnerable road users, including the ones who actually belong on the road with the motorists.