Vascar in Virginia

yes and no...the aircraft or helo measures your time from point A to point B by stopwatch to determine your travelling speed and then call's in the smokies.

[TSi+WRX]

Also, remember, land-based VASCAR can be used between just about any two points of known distance.

Keep your eyes peeled for those white lines (also, here, note that the lines don't necessarily need to traverse the lanes-of-travel - they could easily be on the shoulders), but keep in mind that this particular "tell" isn't always going to be there.

Much like pacing, this is one enforcement technique to be *greatly* feared.

[Fractal]

How can pacing be legal enough to hold up in court? The way I thought radar and lidar worked is that the LEO had a video of your car speeding or some other photograph which was activated by the radar/lidar gun. Does pacing use something similiar?

[TSi+WRX]

^ I'm not a lawyer, so I honestly cannot debate the whys/hows of this particular enforcement method.

However, it's tried-and-true, via "calibrated speedometer."

This method of enforcement has been in-use for decades.