Le 18/08/2011 14:06, Gerard Ashton a écrit :
On 8/18/2011 4:30 AM, mike cook wrote:
Could this be a good argument for getting parking ticket offences
thrown out?
Under current rules, UTC is an approximation to mean solar time at
some meridian that passes through the grounds of the Royal
Observatory, Greenwich (although not necessarily the crosshair of the
Airy Transit Circle). The wristwatch of the traffic enforcement
officer is an approximation to the mean solar time that is in force as
civil time in the UK. Ignoring differences of one hour due to summer
time, the difference between UTC and the civil time is probably less
than one second. (It is less than 0.9 s between UT1 and UTC, and I
would guess the various variations in the plausible locations of the
meridian and the various algorithms for computing mean time would be
less than 0.1 s.) As a rule of thumb, higher accuracy standard should
have a tolerance of 1/3 of a lower accuracy standard that is to be
calibrated. Thus, if there is an uncertainty of +/- 1 s in the meaning
of GMT, the traffic enforcement officer's wristwatch may still be
calibrated with UTC provided the wristwatch need not have an accuracy
of better than +/- 3s.
I would be most surprised if there is an actual written procedure that
traffic officers must follow in setting their wristwatches and a
specified grace period officers must allow before issuing a citation,
but maybe the officers in the UK are better organized than the ones
I've encountered in the USA.
My argument is not that the lawmans watch is not to any particular
accuracy , but that it might be showing some value ( time ) that has no
legal existence. Lawyers like that stuff. A good example is with
Parisian parking meters. It is written in law that anyone selling
anything must accept legally accepted currency .Parisian parking meters
don't accept notes, and the current ones don't even accept coins, having
been swapped with prepaid card or credit card affairs due to robbers
sawing them off at the base to rip off the takings. So you can have
your parking offence canceled by writing Prefect of police to that effect.
Gerry Ashton
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