Anonymous
Anonymous asked in Politics & GovernmentLaw Enforcement & Police · 2 months ago

Officers I have a question that I am certain you can answer.?

Let's say you are on duty, and happen to be stopped at a red light.  You're in the right lane stopped while a car in the left lane is traveling from behind you. Your radar gun informs you that the car was traveling 69 MPH in a 45 MPH zone.  The car stops along side of you, and begins to move when the light turns green.  You pull him over and issue a speeding ticket.  How accurate is your radar gun at determining the vehicle was actually speeding?  

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  • 2 months ago

    TROLL FAIL. A car traveling 69 mph in a 45 mph zone CAN'T stop for the light.

    Modern radar equipment is accurate to within 1 mph in ALL directions regardless of the speed of the patrol vehicle. Besides, the UNTRAINED naked eye is sufficiently accurate to determine the hypothetical vehicle was speeding, and officers are trained to be significantly more accurate than most people.

    Note: The answer referring to angle are technically accurate, but actually WRONG. Modern equipment measures the angle and automatically accounts for it.

    Update to Jon's comment: NO, that IS NOT what any ticket was issued for. The ONLY question is if you were lied to, or if you are the liar.

    • Jon
      Lv 4
      2 months agoReport

      Well my  friend that's what the ticket was issued for. 

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  • Bruce
    Lv 7
    2 months ago

    By state law, our radar guns must be certified to be plus or minus 1 mile per hour.  As far as them being in the other lane, the radar is most accurate when the target vehicle is travelling directly towards the radar unit. Any angle causes something called a "cosine shift". It would be negligible in your example. Another thing about cosine shift, it registers a lower speed so it is always to the advantage of the person being clocked. 

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  • 2 months ago

    The more of an angle between the radar gun and the vehicle the less accurate it will be but in the situation you presented the angle isn't very big and the radar gun rounds down by default anyway.  If there was a large angle between the radar gun and the speeding car the radar gun would show a lower speed than the car was actually traveling.

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  • 2 months ago

    Edit:  10 degrees is not enough to matter. In any event, re read the third sentence n my answer. 

    It is accurate enough.  Note that any inaccuracy due to angles would be to understate the speed of the target vehicle. If you want to claim inaccuracy as a defense then you need to realize the speed estimated by the radar device would be > lower < than the target vehicle's actual speed.  

    • Jon
      Lv 4
      2 months agoReport

      What if the angle of your radar gun was more than 10 degrees off of the approaching vehicle?

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