Legal. The USA's got it right. Legal radar detectors are a blow for freedom.
Illegal. Canada's got it right. Radar detectors help law breakers.
They should be legal. Speeding should remain illegal.
But, don't go by what I say because North Carolina has the strictest and most complete Radar Operator training and operating standards in the Nation.
So alot of Officers in states that have a piddly 3 hour training class won't/don't/ and aren't expected to operate in the same manner.
LIDAR is used for this case because an Officer can pinpoint a specific vehicle instead of shooting out a wide range beam.
However, if there are a few cars, say 5, and one is obviously traveling faster than the others, when the radar displays the higher speed, the officer can use the higher speed to stop the vehicle that is visually going faster.
In NC, an officer is required to have a visual speed estimation of the vehicle that they stop using a radar reading.
And that is what the majority of our 40 hour class consists of, learning to estimate speed visually, and visual estimation testing is a key part of the certification process.
It is also a key part of the 3 year re-certification process.