<human>: I was merging onto a freeway early Sunday morning.  The entrance to the freeway which I take gives a very short merging lane before combining with the oncoming traffic.  Be it Sunday morning, traffic was relatively light compared to Southern California standards and was moving very fast.  Given the short acceleration distance I had to floor it and keep on flooring it to stop the guy coming from behind me from killing me.  That being said, I was rader gunned by a highway patrol and saw him doing it.  However, he was standing on the passenger side of his vehicle, and upon rader gunning me he put the rader gun down, walked about 10 steps to the other highway patrol vehicle behind him and gestured towards my car.  I read somewhere long ago that a radar gun used further than 500 ft away can not be used to ticket you, taking into consideration the speed put on my ticket, and the fact that the cop who rader gunned me had time to lock in a reading and walk back to the other car and tell him what car to pull over and the speed, it's almost impossible that he had gotten me within 500 ft, which gave him 4.2 seconds to do all said things.  Is there something I can use to defend myself in court?  If so what am I missing here??

What I'm asking is

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<bot>: I was pulled over for safely merging onto a freeway by a cop who did not radar gun me but was told to pull me over by the cop who did all in a span of 4.2 seconds.