Taken from Dave Moulton's Blog
The cyclist is riding to the right of the lane and is going straight. The red SUV has just passed him and is also going straight.
The blue car is stopped with his turn signal on waiting to turn left into the side road. As in the Part I scenario, the driver of the blue car can’t see the cyclist because he is behind the red SUV, and also the cyclist cannot see the blue car for the same reason.
It is possible the driver of the blue car has been sitting waiting to turn for some time, and the cyclists has been partially hidden from his view by a steady stream of traffic. Now all the driver sees is a gap in traffic behind the red SUV.
The red SUV passes and the driver of the blue car guns it to turn quickly. It is a small gap in traffic and his only thought is that he must get across before the next car arrives. He is no longer looking down the road otherwise he might still see the cyclist; he is now looking at the side road in the direction he is headed.
The cyclist is either hit broadside by the front of the car, maybe run over, or he runs smack into its side of the vehicle. Even if the driver sees the cyclist at the last moment, car driver and cyclist both have only a split second to act.
The car driver either panics, brakes hard and ends up as a stationary object in the cyclist's direct path; or he underestimates the cyclist's speed and tries the beat him through the intersection. Often a collision is unavoidable the moment the vehicle making the left turn has started the move.
How to avoid this situation.
1.) Think ahead. As I have just mentioned, the blue car has probably been waiting to turn for some time before the cyclist arrives. The cyclist could have made a mental note some 200 yards before he arrived at the point of a potential collision.
2.) If it is safe to do so, take the lane. Signal and move over to the left so you are visible to the driver of the car waiting to turn. Had the cyclist done this, chances are the red SUV would not have passed him, but would have still been behind him. The blue car would have had to wait for both the cyclist and the SUV to pass before turning.
Also, if the cyclist moves to the left, nearer the center of the lane, should the blue car turn, the cyclist has more opportunity to simply steer a course behind the vehicle.
3.) Listen for cars behind you, they are your safety buffer. If there are none and there is any doubt that the turning driver has seen you; be ready to make a panic stop.
If the car driver has not seen the cyclist, an accident can still be avoided if the cyclist is aware ahead of time, what could happen. Otherwise, given the cyclist's speed, the reaction time, and the distance it takes to stop on a bicycle..... Well, you get the picture.
In these scenarios I have used an SUV as an example of a vehicle blocking the view of a turning driver. More often than not the vehicle you are following is a large commercial box van, truck, or bus, making the situation even worse.
The onus is of course on the driver of the vehicle entering or turning from a highway, but as it is the cyclist has the most to lose in such a situation, it behooves him or her to ride defensively at all times.
Don’t be a victim. Always think ahead and look for potential hazards. Remember it is not that you are actually invisible; it is more an illusion that the cyclist is not there, brought on by years of conditioning and not being aware of bicycles.
Multiple times, every day for years a driver waits for a gap in traffic to make a left turn. When he sees it he goes for it; always without mishap. Then one day there is a cyclist in that gap.
Don’t let it be you; don't be the Invisible Cyclist.