[s-cars] Speeding ticket technicality

[Kirby Smith]

If I understand you correctly, if the police vehicle is driving while
having a radar adjusted for a side of road offset angle of 30 degees,
then conceivably one could get a ticket for a speed that is the ratio of
1 over the cosine of 30 degrees higher than he was going.  Or, any
number less than that depending on the relative angles.

In any case, the measured speed is highest when approaching the radar
with one's velocity vector parallel to the radar axis.

kirby


Bob Frizzell wrote:
> 
> Kirby,
> The cosine effect is used because the radar measures the longer (hypotenuse)
> vector.  A change in this vector results in a smaller change in the adjacent
> vector, which represents the vehicle's velocity along the road.  So the true
> speed is the measured speed times the cosine of the angle between the line
> of sight and the velocity vector. Apparently radar that is stationary at the
> side of the road is generally aimed at 30 degrees to the roadway and the
> registered speed on the police radar is adjusted accordingly.  I tried the
> cosine law defense without realizing the radar was calibrated to account for
> it, only to find out later that it was. The judge, although not perfectly
> clear on it, said that the radar must be adjusted for it otherwise none of
> the speeding tickets from roadside radar would be valid.  It was interesting
> when I showed some simple right triangle trigonometry to the prosecutor and
> he said, "this is way beyond me"!
> Bob
> ----- Original Message -----
> From: "Kirby Smith" <kirby.a.smith at verizon.net>
> To: "Varon H. Fugman" <vfugman at globaldialog.com>
> Cc: <s-car-list at audifans.com>
> Sent: Monday, March 15, 2004 6:29 AM
> Subject: Re: [s-cars] Speeding ticket technicality
> 
> > I wouldn't invoke the cosine effect if I were you.  The measured speed
> > is the true speed times the cosine of the angle between the measurement
> > line of sight and your velocity vector.  In other words, you are going
> > faster than measured.
> >
> > kirby
> >
> >
> > "Varon H. Fugman" wrote:
> > >
> > > I would concur with the advice to consult an attorney.
> > >
> > > I once had a ticket where the officer circled "pm" instead of "am"
> making it
> > > 12 hours off.  However, I was unable to leverage this sufficiently
> defending
> > > myself, although I did get the officer to (very reluctantly) admit that
> he
> > > had made a mistake and the ticket was wrong.  But I couldn't get him to
> > > admit that the speed on the ticket might also be wrong!  Or that he
> might
> > > have made another mistake.
> > >
> > > My questioning of the officer did elicit some laughter from the
> courtroom,
> > > but I don't think that improved my case in the judges eyes.
> > >
> > > One other option you might consider if your state permits it is to sign
> up
> > > for defensive driving.  That what I did for my last ticket rather than
> try
> > > to fight it.  Of course, gotta keep my record clean for a whole year
> now!
> > >
> > > However, with a good attorney you might have at least 50/50 odds getting
> it
> > > dismissed because of the error... especially if your attorney frequently
> has
> > > lunch with the DA!
> > >
> > > Start lining up your witnesses to testify where you were on that date
> and
> > > time!
> > >
> > > Varon
> > > '95 urS6 keeping is close to the limit... most of the time!
> > >
> > > P.S. If he clocked you while you were coming around a corner, depending
> on
> > > where he was relative to you, there's always the possibility of the
> cosine
> > > effect.  This is where the straight-line closing speed between you and
> the
> > > oncoming police car is higher than your actual speed along the curve.
> > >
> > > P.P.S. And with moving radar one should also rule out shadowing...
> Could
> > > there have been a large truck or train moving slowly that the radar
> could
> > > have mistaken for the ground?  This too can result in a higher than
> actual
> > > speed reading.  The officer is supposed to verify that the "ground
> speed"
> > > displayed on his moving radar unit matches his speedometer, but in their
> > > hurry to make a U-turn and pull someone over they frequently omit this
> step.
> > > Of course, that doesn't mean they will admit it in court!
> > >
> > > P.P.P.S. And of course we need to make sure both the radar unit and
> > > speedometer in the patrol car were both recently calibrated.  If it has
> been
> > > too long, they really aren't trustworthy, are they?
> > >
> > > P.P.P.P.S. Based on my experience, none of the above information will
> help
> > > trying to defend yourself in traffic court!
> > >
> > > P.P.P.P.P.S Isn't it funny how they police never want to admit that
> there
> > > are serious shortcoming with radar... until they need the justification
> to
> > > purchase expensive laser guns!
> > >
> > > _______________________________________________
> > > S-CAR-List mailing list
> > > S-CAR-List at audifans.com
> > > http://www.audifans.com/mailman/listinfo/s-car-list
> > _______________________________________________
> > S-CAR-List mailing list
> > S-CAR-List at audifans.com
> > http://www.audifans.com/mailman/listinfo/s-car-list