The law is different in each country of the world, especially on a hot topic like this. For this reason, we can not provide any universal answers here. To get answers to legal questions in Germany, Austria and Switzerland, please switch to the german version of this page.

No. All modern "guns" used for speed control use the LIDAR technology which works with laser. Actual radar guns were used many years ago and are by far outdated.

In principle it is not important which device was used. The measurement method the device uses is what counts.
- Radar: below 100 km/h: 5 km/h tolerance, above: 5% tolerance
- Laser: below 100 km/h: 3 km/h tolerance, above: 3% tolerance

In addition to that you have your tachometer tolerance, depending on the brand of your car this means 2-5% extra.

Yes. But that specific speed is (depending on the model of the speed trap) somewhere between 320 and 400 km/h so that could get a little difficult on public roads.

Yes. Technically this is possible, but most countries pick one direction and make most speed traps work with it.

No, ordinary ka-band radar speed traps can not do that. If two speeding vehicles pass a device like that at the same time, at least one of them won't get a ticket. Modern devices using multaradar, also known as tracking radar or even using laser, are able monitor multiple lanes at the same time.

This is different in each country of the world. For this reason, we can not provide any universal answers here. To get answers for unmarked police cars in Germany, Austria and Switzerland, please switch to the german version of this page.