In England: http://www.bluelightaware.org.uk/?p=239

When you're driving you either pull over and slow down (if it's safe to do so); or you keep driving at a safe speed and pull over when it's safe to do so.

If you're at a traffic light you can either try to move to the side without crossing the line; or you can stay where you are and allow the emergency vehicle to sort it out; or you can cross the line if a police officer directs you to do so (and blue lights is not a direction).

That's why EMS drivers love Opticomm and other traffic preemption devices -- The direction that you are traveling gets a green light -- keeping traffic in the direction that you're moving flowing (so, in theory they merge to the right, but, that's another topic for another day) -- and you get protected turn signals (so that traffic ahead pays attention to the red lights at the signal, not your red lights that they may not be able to see or notice.

The short answer is that we will expect you to move forward and to the right whenever possible. Above all, we don't want you to put yourself into a dangerous position.

If you're at a red light with an emergency vehicle behind you, the best course of action might be to make a (safe!) right on red and then go around the block to get back on your original course.