Quote:
Originally Posted by theDreamer
My understanding is that a radar should be able to zero it self while moving which would allow the cop to pick up your speed if traveling in the same direction.
Now the same idea can be figured for two cars traveling in an opposite direction, even after they pass each other, once the beam returns it will use a doppler calculation to determine your speed. I mean, all radar is technically inaccurate since it is based on a beam traveling over a distance and returning and then calculating the variables. More variables the great the risk of inaccuracy.
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That actually makes sense, I think. Assuming the cop has a radar gun pointing backwards, if the radar unit self-zeroes, then when it measures the speed of a car going in the opposite direction, it'll just read in the negative, right? In other words, if it says -60mph, then that just tells the cop that I was doing 60mph. Now let's say he does this on a car that is behind him and going in the same direction. If the reading was -10mph, it would just mean that the car was going 10mph slower than him. If it read +10mph, it would mean it was going 10mph quicker. In both cases, he'd just add or subtract it from his own speed to ascertain the other car's speed.