[net.auto] speedometer calibration and radar

jla@inuxd.UUCP (Joyce Andrews) (02/25/85)

Yesterday was my first day on the "open road" with my brand new 
Daytona.  It ran beautifully, cornered nicely, accelerated
smoothly.  I set cruise control at exactly 55.  I was pleased 
that the cruise control operated smoothly--not varying by ten mph
like the cruise control in the Chevy Caprice company car I used 
to drive.  I gave the speedometer careful attention--I KNOW it 
said 55 mph for a long time, with very little variation.  I got 
a $35 speeding ticket (T55 radar in moving mode) for going 71 
miles an hour!  

I was behind a pick-up truck for sometime, with about the same 
distance between us all that time.  The truck did not get picked 
up.  I didn't think to ask at what speed he clocked the truck.  I
tried my own little experiment, using mileposts and my digital
watch, and took more than a minute at 55 to reach the next
milepost, but I can't swear to the accuracy of the mileposts.  In
all honesty, however, the other traffic on the interstates seemed 
to be going more slowly than usual the whole day.

My questions:  What are the chances that my speedometer is 15 mph
off calibration?  How can I find out?  What are the chances that 
the radar (operated by an Ohio State Patrolman, not some local
Wyatt Earp) screwed up?  Should I try to fight it, even though it
is out-of-state 150 miles from home?  Am I more likely to get
this treatment now that I have a sporty looking car than I would
in a sedate sedan?

                           Joyce Andrews
                           AT&T Consumer Products
                           Indianapolis, Indiana
                           ihnp4!inuxc!inuxd!jla
 

alien@gcc-bill.ARPA (Alien Wells) (02/27/85)

> ... after being ticketed for 71 with cruise on at 55 ...
>My questions:  What are the chances that my speedometer is 15 mph
>off calibration?  How can I find out?  What are the chances that 
>the radar (operated by an Ohio State Patrolman, not some local
>Wyatt Earp) screwed up?  

One thing that police *often* do is to serve up 'leftovers'.  They get some
guy for 71, then they keep using that same radar reading for other cars.  You
can check for this, if you want, by subpoenaing (sp?) the record of the officers
tickets that he gave out that day.  If there is a string of tickets for 71, you
can probably get off.

However, if the ticket is from out of state, you may well be best off just 
paying the ticket and paying it quickly.  If you give them no hassles, the
ticket is rarely reported to your home state, and thus it does not appear as
points on your record.  If you fight it or don't pay, guess who are the first
people they tell?

					Alien

44735600@sdcc3.UUCP (Smedley, the Entertainment Orange) (02/28/85)

Stories like this make me glad the California Highway Patrol can't
use radar on the freeways...

				   E. Orange

awd@byucsc.UUCP (A. W. Dunstan) (02/28/85)

> My questions:  What are the chances that my speedometer is 15 mph
> off calibration?  How can I find out?  What are the chances that 
> the radar (operated by an Ohio State Patrolman, not some local
> Wyatt Earp) screwed up?  Should I try to fight it, even though it
> is out-of-state 150 miles from home?  Am I more likely to get
> this treatment now that I have a sporty looking car than I would
> in a sedate sedan?
> 
It shouldn't be too hard to find a shop that will calibrate your speedometer
to within a very small percentage.  It may take some looking, but they can
be found.  Some speedometers can be way off, right from the start. 

Another thing should be noted - most radar guns have a "calibration" mode.
Press a button, and it calibrates itself.  The number used for calibration
is usually around 70 MPH.  Odd, isn't it?  If you were fairly close to the 
truck, the radar will pick up the truck, and not you.  Actuall it picks up
both, but the signal from the truck overpowers the signal reflected from
your vehicle (assuming your vehicle is significantly smaller than the truck.)

It might be worth your while to see how accurate your speedometer already
is.  If it turns out that it *is* accurate, find a lawyer and talk to 
the judge, I'd say.

Happy Motoring!
 -- 
|+|+|+|+|+|+|+|+|+|+|+|+|+|+|+|+|+|+|+|+|+|+|+|+|+|+|+|+|+|+|+|+|+|+|+|+|+|+|+|

No one should be held responsible for these remarks, least of all me.

            - byucsc!awd  (A. W. Dunstan)

bmt@we53.UUCP ( B. M. Thomas ) (03/03/85)

The error in a speedometer's calibration is rarely if ever a fixed offset.
Rather, a ratio of error is present, which makes it greater at higher speeds.
I was ticketed for doing 52 when I happened to be watching my speedometer
stay very close to 40.  Obviously, I checked the calibration immediately
and found that when my speedometer said 30, my dad's, which I was following
very closely, said I was doing about 40.  It is very possible that your
speedometer was in error by this much, in fact, the commonness of this
state of affairs is one reason that a lot of police officers give you as 
much as a 10 mph leeway.

ems@amdahl.UUCP (ems) (03/05/85)

> 
> Stories like this make me glad the California Highway Patrol can't
> use radar on the freeways...
> 
> 				   E. Orange

The CHP *can*, has, and does use radar on the freeways.  They are
units 'loaned' by a local agency and are rather rare, but they do exist!!!
The legislature has always line item vetoed any appropriation for
radar for the CHP.  No budget therefore no units... Until some
enterprising local police loaned some to the CHP's... sigh.

E. Michael Smith  ...!{hplabs,ihnp4,amd,nsc}!amdahl!ems

Computo ergo sum

The opinions expressed by me are not representative of those of any
other person - natural, unnatural, or fictional - and only marginally
reflect my opinions as strained by the language.

cal@pyramid.UUCP (Craig Alan Levin) (03/07/85)

>> Stories like this make me glad the California Highway Patrol can't
>> use radar on the freeways...
>> 
>> 				   E. Orange

> The CHP *can*, has, and does use radar on the freeways.  They are
> units 'loaned' by a local agency and are rather rare, but they do exist!!!
> The legislature has always line item vetoed any appropriation for
> radar for the CHP.  No budget therefore no units... Until some
> enterprising local police loaned some to the CHP's... sigh.
> 
> E. Michael Smith  ...!{hplabs,ihnp4,amd,nsc}!amdahl!ems

Both of you are partially right!  The CHP does use radar, if
purchased for them.  But they cannot use it on the "freeways", as
defined by the State Legislature.  If they do so you may
challenge the citation as a "Speed Trap", specifically outlawed
in the days of hidden speed limit signs as one would enter a
small town.  They may use the provided radar on roads
under the jurisdiction of the government body that provided them.
Eg.  Contra Costa County provided 2 units for usage only on roads
within their county, outside of incorporated communities.  This
information was published in Road & Track a few years back.  

Additional information was given as to what constitutes a valid
radar citation in California.  To summarize, the citing authority
must provide a recent survey, taken prior to the citation, that
justifies the posted speed, based upon median speeds over a 6
month period.  If I find the time I will dig out the specific
issue from my archives.

hav@dual.UUCP (Helen Anne Vigneau) (03/08/85)

<*munch*>

=> However, if the ticket is from out of state, you may well be best off just 
=> paying the ticket and paying it quickly.  If you give them no hassles, the
=> ticket is rarely reported to your home state, and thus it does not appear as
=> points on your record.  If you fight it or don't pay, guess who are the first
=> people they tell?
=> 
=> 					Alien

Uh, I beg to differ.  While we were in Utah about a year and a half ago on
vacation, my loves-to-drive-fast mate was stopped by a state trooper for going
70 in a 55 out on a back road between SLC and Bryce Canyon National Park.
The fine was something like $5.00 plus $2.00 for every mile over the speed
limit.  He paid the ticket, but surprise surprise, when he got a copy of his
record with his insurance renewal, what do you think showed up on it?

Helen Anne

     {ucbvax,ihnp4,cbosgd,hplabs,decwrl,unisoft,fortune,sun,nsc}!dual!hav 

             If a man does not keep pace with his companions,
             perhaps it is because he hears a different drummer.
             Let him step to the music he hears,
             however measured or far away.