Home Forums Massachusetts Motorists Issues LIDAR in a curving tunnel

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    yoguh12
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    For the sake of simplifying the story…going to just go with bullet points –

    – Received ticket in Massachusetts while driving in a tunnel with slight curvature like ” ( “.
    – Wed at 6pm with rush hour traffic
    – Car in front of me was a white Malibu and got pulled over
    – Officer was walking to the outer lane to tell the car to pull over to the emergency lane
    – I am driving a white Audi A4 also gets waved over since I am in the lane behind the white Malibu
    – There was distance between me and Malibu so I saw the brake lights hit with reasonable distance away
    – Lidar gun was on the top of the trunk of the officer’s car as I was pulling over
    – 150 dollar ticket for going 60 in a 45 zone. Said I was going 62 but to be nice, he’d write 60.

    – Ticket information is all correct, but says 519′ 6 on there. I am assuming this is the distance he was away from me when he “clocked” me.

    Defense items:
    1) As I have researched, LIDAR is subject to cosine errors like radar. If the tunnel is curving, then cosine error would be amplified.
    2) LIDAR relies on reflective surfaces like the license plate, but other reflective surfaces will also mess up the reading. The tunnel has white ceramic tiles against the walls, also the areas around my license plate are matte, and there is a chrome grille above the license plate. All are sources of disruption to the accuracy of the reading.
    3) If he had clocked me in at 519ft, it must have been after the fact that he 1) visually inspected my speed and 2) used LIDAR. If all of that takes around 3 seconds, at 60mph, add another 264 ft to the 519, and we are looking at visually inspecting me at 783ft!! I don’t know how accurate his eyes are, also add on he would need to use LIDAR at that sort of distance too.

    What do you guys think? Anything else that I seem to be missing?

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