News: Physicist claims victory over ticket with physics

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Rusty Haight
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News: Physicist claims victory over ticket with physics

Post by Rusty Haight »

The article "Physicist claims victory over traffic ticket with physics paper" is about how Dmitri Krioukov affiliated with the "Cooperative Association for Internet Data Analysis" at the University of California, San Diego argued that a police officer who wrote him a ticket for failure to stop the stop sign made a mistake as a function of an illusion given his perpendicular position to the defendant's path and location of the stop sign. He went on to write a paper titled "The Proof of Innocence" which is available from the Cornell University Library and attached below. The abstract reads:
We show that if a car stops at a stop sign, and observer, e.g., a police officer, located at a certain distance perpendicular to the car trajectory, must have an illusion that the car does not stop, if the following three conditions are satisfied: (1) the observer measures not the linear but angular speed of the car; (two) the car decelerates and subsequently accelerates relatively fast; and (three) there is a short-time obstruction of the observer’s view of the car by an external object, e.g., another car, at the moment when both cars are near the stop sign.
I think the third condition is the one that may have set the judge over on the side of "not guilty." After all, if you lose sight of the defendant vehicle's path, how can you say he did or did not stop? Personally, I don't think this was so much arguing the physics as much as it was "muddying the waters" and relying on the idea that another vehicle had obstructed the officers view of the defendants car in the stop sign. Nonetheless, it is something of an "interesting read." The other interesting thing here is to compare the way the author of the online news account describes the defense with what the professor wrote in his paper.


Can anyone spot the flaw (mentioned in the news article)?
Attachments
The Proof of Innocence.pdf
(391.95 KiB) Downloaded 1080 times
- Rusty Haight
Collision Safety Institute

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wwmc
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Re: News: Physicist claims victory over ticket with physics

Post by wwmc »

O.K., I'll bite. The diagram in both the news article and technical paper shows the officer's position to be a 90-degree angle from lane L at stop sign S. The technical paper also describes the officer as being located on a road that connects to lane L perpendicularly. That would put the officer on the wrong side (or beyond) of the connecting road.

The angle at triangle point S was more than 90-degrees, also allowing a 'frontal view' of the vehicles at the stop sign (or point on the roadway where a complete stop was required).
Bill McCombs

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