Sudden slow downs. Why?

In article . com>,
Old Wolf > wrote:

>Laser guns (LIDAR) don't have this problem.. although I managed
>to get lasered and not get a ticket, the other day. The cop must
>have not been paying attention, or something. I braked as soon
>as my detector went off, and noticed that he kept the gun trained
>on me all down the length of the straight (usually, lasers hit you
>once and stop).

LIDAR guns DO have the same problem; they need to bounce sufficient
pulses off of you to get a reliable reading.
--
There's no such thing as a free lunch, but certain accounting practices can
result in a fully-depreciated one.

"Matthew Russotto" > wrote
> In article . com>,
> Old Wolf > wrote:
>
>>Laser guns (LIDAR) don't have this problem.. although I managed
>>to get lasered and not get a ticket, the other day. The cop must
>>have not been paying attention, or something. I braked as soon
>>as my detector went off, and noticed that he kept the gun trained
>>on me all down the length of the straight (usually, lasers hit you
>>once and stop).
>
> LIDAR guns DO have the same problem; they need to bounce sufficient
> pulses off of you to get a reliable reading.

IIRC (from a 10-15 year old Car & Driver magazine article), radar needs
to read a constant speed for 0.2-0.4 seconds before it will lock a reading.
However, LIDAR, because of the technology and narrow beam width, takes
a much much shorter time: on the order of 0.01 seconds.

Floyd

fbloogyudsr wrote:

> IIRC (from a 10-15 year old Car & Driver magazine article), radar needs
> to read a constant speed for 0.2-0.4 seconds before it will lock a reading.
> However, LIDAR, because of the technology and narrow beam width, takes
> a much much shorter time: on the order of 0.01 seconds.

According to the LTI Ultralyte instruction manual, it needs about 1/3 of
a second. There's also the issue of not maintaining aim on the same
surface of the vehicle for the entire time (which may or may not result
in an error reading).

On 11 Jul 2005 17:51:23 -0700, "Old Wolf" >
wrote:

>Radar takes a couple of seconds to get a fix. Then, the cop has to
>visually identify which car is going the fastest. If there are 2
>cars in the vicinity, (including cars on the other side of the road),
>the radar will only indicate the speed of the fastest-moving one.
>The cop must identify which of the cars he can see is the one that
>was speeding.

You are clueless on this issue. Radar is almost instantaneous. Radar
waves travel at the speed of light, and light takes a very small time
to travel from the gun to your car and back. The computer takes very
little time to calculate your speed. So in less than a tenth of a
second, the gun reads the speed. Further, the courts have ruled many
times that a cop has no obligation to identify who is speeding.
Rulings that the front car is the speeder are prevalent. No judge has
ever ruled in favor of someone arguing the guy behind him was
speeding. Cops are severely incapable of determining which vehicle is
going faster.

Harry K wrote:
> Two lane highway, posted 60, flow 65-67, few passing chances
>
> Happens constantly, traffic moving comfortably along when it goes over
> a hill or around a corner and suddenly slows to 60. Yep, cop car
> parked on shoulder.
>
> WTF is the point of slowing to the posted? If he wants you, he already
> has you as soon as he sees your car. His radar is far faster than your
> reflexes. It is too late to slow down. The likelyhood of getting a
> ticket (at least on this highway) doing the flow is extremely remote
> anyhow.
>
> Now I can understand people slowing for a cop cruising at the posted or
> just above it as he might be trolling for an easy ticket.

Not all cops are out there for the purpose of writing tickets. Some are
there in order to cause this very slowdown, and as long as only one or
two cars (at most) are willing to continue "speeding", the cop will win.

The silver lining of the old 55 limit was that it created such a huge
"civil disobedience movement" that cops were unable to intimidate their
targets by using the above technique. It would be better, I feel, if
most drivers continued to disobey until the limits reached reasonable
levels.

John David Galt wrote:

> The silver lining of the old 55 limit was that it created such a huge
> "civil disobedience movement" that cops were unable to intimidate their
> targets by using the above technique.

That reminds me of the one time I saw a cop parked in the grass off the
right shoulder while driving on I-287 in NJ. This was before NJ
increased the speed limit beyond 55 mph. Everyone, including myself,
kept it between 70 and 75 mph.

> Not all cops are out there for the purpose of writing tickets. Some are
> there in order to cause this very slowdown, and as long as only one or
> two cars (at most) are willing to continue "speeding", the cop will win.
>
> The silver lining of the old 55 limit was that it created such a huge
> "civil disobedience movement" that cops were unable to intimidate their
> targets by using the above technique. It would be better, I feel, if
> most drivers continued to disobey until the limits reached reasonable
> levels.

You don't have to worry about most drivers continuing to disobey, but if you
are waiting for the limits to reach reasonable levels, I'm afraid you will
have to wait until sometime when we're all flying to work on the backs of
pigs. -Dave

Ted B. wrote:
> > Not all cops are out there for the purpose of writing tickets. Some are
> > there in order to cause this very slowdown, and as long as only one or
> > two cars (at most) are willing to continue "speeding", the cop will win.
> >
> > The silver lining of the old 55 limit was that it created such a huge
> > "civil disobedience movement" that cops were unable to intimidate their
> > targets by using the above technique. It would be better, I feel, if
> > most drivers continued to disobey until the limits reached reasonable
> > levels.
>
> You don't have to worry about most drivers continuing to disobey, but if you
> are waiting for the limits to reach reasonable levels, I'm afraid you will
> have to wait until sometime when we're all flying to work on the backs of
> pigs. -Dave

I have found following a police officer at a respectful distance to be
an excellent way to make progress through traffic at super-legal speeds


nate

James C. Reeves wrote:
> "Larry Bud" > wrote in message
> oups.com...
> >> That is, a cop can't use radar or lidar before he suspects
> >> that you are speeding.
> >
> > Oh come on. Let's talk about reality. The reality is that cops sit on
> > the side of the road with their radar on waiting for the numbers to
> > register higher than the speed limit. Then the christmas tree lights
> > up and he gets one more for his monthly quota. No probable cause
> > necessary.
> >
>
> Yep, that's the way they do it here. The "tag" just about everybody that
> drives by.

I just saw that this AM on the Dulles Toll Road, officer on motorcycle
at the side of the road running continuous radar. That still works in
VA as radar detectors are illegal.

nate

In article >,
Arif Khokar > wrote:
>John David Galt wrote:
>
>> The silver lining of the old 55 limit was that it created such a huge
>> "civil disobedience movement" that cops were unable to intimidate their
>> targets by using the above technique.
>
>That reminds me of the one time I saw a cop parked in the grass off the
>right shoulder while driving on I-287 in NJ. This was before NJ
>increased the speed limit beyond 55 mph. Everyone, including myself,
>kept it between 70 and 75 mph.

The same thing happens in Massachusetts, but in Connecticut traffic
ahead of me slowed to 60 in a 65 zone at the sight of a police car.

--
John Carr )