Some good info in this thread.
I'll expand a bit on 'lasers'. These aren't really lasers, of course, they are simply a very focused beam of light. Used properly, they are not avoidable without resorting to active jamming. The catch? They are VERY rarely used properly. Their effective range is much shorter than radar, which gives them some odd characteristics:
- Police who are familiar only with radar will try to use them at longer ranges, effectively alerting anyone with a detector with enough time to spare.
- The shorter range means that police using them properly will usually be very easy to spot unless they are very well disguised, which tends to happen only with police trying to make money rather than concerned for safety. (Not that lower speeds does anything but increase risk, but that's another topic.)
- The shorter range also means that when used properly, you won't get any warning from the cars ahead of you because the angle is too steep. They won't be fired directly down the road, alerting dozens of cars - instead, they are fired across at an angle, alerting a few cars at most, especially when you consider the beam width is measured in feet instead of dozens of feet.