I was waiting for someone to ask that. A phantom shift is shutting off the lights of the car and quickly shifting to the slower lane (one lane over maxium, never multi lane hops), and putting the headlights back on. If you do it right your car becames "invisable" to the cop for 2-3 seconds while you shift over and slow down and by the time he is near you, you should be over to the slower lane, doing the speed limit. The result of a correctly done phatom shift is a very confused cop that goes back to waiting for his next ticket.
There are of course other factors to this..you need other cars on the road, being the only car on the road will void this unless you go for a stealth park but thats not this. It also only works on highways or other roads without a lot of road lights...too much lights will void the phantom or vanishing part of the trick.

