Mathematicians: Help me stick it (back) to The Man

January 4, 2006 9:29 AM

Mathematicians: Help me stick it (back) to The Man: Is 1.75 miles enough for a vehicle that started off moving slower than the rest of traffic to build up speed, pace a car and accurately determine its speed?

Picture this:
Two Cars. One (me) driving at 70-75 MPH in the number one lane on a four lane freeway; the other (cop) just merging onto the freeway from an on ramp, probably going between 45-60 MPH, working his way up to 65. Weather is clear, freeway is mostly empty.

Within 1.5 to 1.75 miles the cop pulled me over for passing him.

How mathematically does this work?

Is 1.75 miles enough for a vehicle that started off moving slower than the rest of traffic to build up speed, pace a car and accurately determine its speed?

It seems to me that he would have had to travel at an incredible speed to catch up to a car that was moving from 15 to 20 MPH faster than him, and even if he did does the speed he caught up to me at count for anything?

How fast would he have to go to catch up to me?
How far would he have to travel to accurately gauge my speed via pacing?

There has got to be some sort of math behind this that I can use in my defense but I suck at math. Please help.


(Please no lectures on how I should just pay the ticket and go to traffic school.)



(Furthermore, to help understand why I am fighting a ticket in this manner:

There is no mention of Radar on my citation, so if the officer claims to have me on Radar I can use the defense that there is no way to determine the accuracy of his Radar equipment since he did not write in his Radar information (ID number or what ever).

Also the officer did not write in his Patrol Vehicle unit number on my citation, without which there is no way to verify the accuracy of his speedometer, and no way to accurately gauge my speed as a result.)

posted by thefinned1 to law & government (25 comments total)

He's already going 45mph? Then yeah, he can certainly figure out that you're speeding within 1.5 miles. If I remember correctly, cops are trained to estimate the speeds of other vehicles, and that estimation is as valid in court as the reading from a radar gun.
posted by bshort at 9:34 AM on January 4, 2006

Let's assume at starting point A - the point where he is merging on to the ramp at 60mph, and you are going 70mph, you are even.

For him to accelerate to 70mph and pace you is rather trivial, as it's only 10mph and should take no more than a few seconds.

In 1.75 miles at 70mph, we're talking about around a minute and a half worth of time to pace you - that's a long time.

Even if he only paced you for, say, 30 seconds, and therefore had 1 minute to catch you -- if you're say, 1/4 mile ahead of him, a mere 15mph faster than you is enough to catch you in a minute.

Sorry dude, I think you're busted here. However, if you show up to court, the cop may not show up just for a speeding infraction, and the ticket may just get thrown out anyway.

I'd talk to a lawyer and ask his/her advice, but I don't think math is going to help you here.
posted by twiggy at 9:36 AM on January 4, 2006

assume you are traveling at 70 MPH (103 feet/sec). assume the officer merges at 40 MPH (59 feet/sec). he sees you and punches it; i assume a constant acceleration of 3 MPH/sec (4.5 feet/sec^2), which is probably less than the actual acceleration of a highway cruiser.

your position: x = 103 fps * t
his position: x = 59 fps * t + 1/2 * 4.5 fps * t^2.

he catches you when your x equals his x, so setting the two right-hand sides equal to each other, you have a quadratic equation in time:

0 = (54 fps) * t + 2.25 fps * t^2
54 * t = 2.25 * t^2
54 = 2.25 * t
t = 54 / 2.25 = 24 seconds. at 103 feet/sec you have traveled 2472 feet, or a little over half a mile.

so, in other words, sorry dude. he had plenty of time to catch up to you and pace you within 1.75 miles.
posted by sergeant sandwich at 9:46 AM on January 4, 2006

I think attacking the officer and court with a show of shaky math is a good way to obtain zero leiniency. Do traffic school or suck it up and ask for a reduced judgement. That's how the world works, sorry.
posted by kcm at 9:54 AM on January 4, 2006

I don't think you need to consider math. The kind of cars most ticket cops drive will do 0 to 60 in under 10 seconds. 45 to 65 (or whatever the posted limit is) takes no time at all.

Once he's at the posted limit all he has to do is ascertain that you are continuing to put distance between you and he knows you're speeding. Lack of radar likely won't do you much good; odds are good he can eyeball your speed pretty accurately and that the court will consider him of sufficient expertise in that matter.

If you really want out of this, you need a better approach. Boing boing blogged about Ticket Assassin, and since you're in CA you can use their solution.
posted by phearlez at 10:04 AM on January 4, 2006

A Police Interceptor should do a standing quarter mile in about 14 seconds and end up at a speed of about 100 mph. Even under less ideal conditions then a test track you are owned. If you show up, most DAs will plead you to a lower or no point ticket, for more money and court cost though. Still, I would rather my money go to the government than to an insurance company.
posted by caddis at 10:07 AM on January 4, 2006

Cop cars can go from 45 to 70 in... well pretty damn fast.
posted by Witty at 11:15 AM on January 4, 2006

jjg writes "Do you really want to be the sort of person who'll use any loophole to avoid taking responsibility for their actions?"

Don't we all want to be that person? Seriously, who wants to pay a speeding ticket?
posted by mr_roboto at 11:29 AM on January 4, 2006

I got out of one of my tickets (also in CA) just by writing a letter to the court. I was doing 85 in a 65 zone on a completely empty highway at 1am on a weeknight in the middle of nowhere. My letter argued that the intent of speed laws is to keep the general public safe from me, since there wasn't anybody around, there wasn't anyone to protect, and the law shouldn't apply in this case. I doubt this argument actually meant anything, it's more likely that the ticketing officer probably didn't respond. In any event, it was dismissed.

jjg said: Do you really want to be the sort of person who'll use any loophole to avoid taking responsibility for their actions?

You make it sound like he hit somebody.
posted by darkness at 11:32 AM on January 4, 2006

Was the pullover videotaped?

Here in the UK, the police tail a car for a measured distance, videotaping all the while. The distances are usually denoted by marks on the road (which I thought were called NAVCAR marks but they don't google up as that). On a motorway, these are the white squares that can be seen at seemingly random spots, midlane. Anyway, the point is that the videotape shows the mark at the beginning, the mark at the end, and the time between. Given that, there's absolute no doubt about calculating the average speed. The kicker is that, if it's disputed in court the emphasis is on 'average' speed, as in "that's the average speed the defendant was travelling at, but clearly at some point they must have been travelling faster than that." At that point, you're stuffed.
posted by veedubya at 11:59 AM on January 4, 2006

Since your math would be predicated on you speeding to begin with, it might not work in your favor.
posted by sad_otter at 12:01 PM on January 4, 2006

Dang, my VW Jetta wagon will do 0-60 in less time than that.

I'm under the impression that in many states now, photo radar and laser devices no longer need to be identified on tickets - so there's no reason to think that he didn't actually clock you from behind or even another lane, unless you have proof to the contrary.
posted by luriete at 12:03 PM on January 4, 2006

It's the principle of it. I was traveling at a safe speed on a mostly empty stretch of freeway.

If the cop had done his due diligence and wrote his radar number and/or cruiser number on the citation I might not have such a problem with it.

Instead he wrote "Passed CHP" which is not a crime.

I used tickets to fight my ticket via mail and lost so I requested a Trial De Novo and will appear in court.

Sure, I have to take a day off of work and drive 150 miles to court, but damnit, it's principle.

Besides:

The Basic Speed Law, CVC 22350, states: "No person shall drive a vehicle upon a highway at a speed greater than is reasonable or prudent having due regard for weather, visibility, the traffic on, and the surface and width of the highway, and in no event at a speed which endangers the safety of persons or property."

As an American it is your right and duty to stick it back to the man.
posted by thefinned1 at 12:10 PM on January 4, 2006

veedubya - They're called VASCAR, I believe.

What sad_otter said, in the first place.

A quickie on how most traffic courts work (At least in Oregon, which is where my experience trying to worm out of tickets comes from):

1) The officer gets sworn in. At that point the must tell the truth or perjure themselves.
2) You are allowed to cross-examine the officer without being sworn in. At this point, you MAY NOT testify in any way, shape or form. Everything that comes out of your mouth must be a question.
3) You are asked if you would like to be sworn in or rest and hear the judgement.
4) If you are sworn in, the judge can ask you ANYTHING and you may not tell a mistruth or you can be jailed or fined for Contempt of Court. (Unlikely in traffic, but ... *shrug* it certainly doesn't help your case.) You must also answer any questions.

The only way to win a traffic case in a court that's set up like that is to ask the officer questions that force them to give answers that call their testimony into question. Traffic courts work off of a "preponderance of evidence" basis; in other words, the cop's word, due to their training (which they will identify, state, and itemize in the first part of their testimony), is worth more than yours... by about a 60/40 or 75/25 ratio, depending on who you ask and how crotchety the judge is feeling that day. Your mission, by asking them questions, is to reduce the worth of the officer's words and to rebalance that to 40/60 in your favor.

In your situation, you don't want to be sworn in because the judge can ask you, "Were you speeding?" and you have to answer "Yes" or get clobbered. Beware of that. Your only method of presenting the math that we've just discussed (which isn't in your favor anyway) is to be sworn in.
posted by SpecialK at 12:14 PM on January 4, 2006

An officer needs only a short distance to do a pace and issue a summons. As long as the officer can articulate that he or she followed your car from a consistant distance maintaining a regular speed for 1/8 mile, 1/4, 1/2 or even 1 mile then you have no win. The reasonable speed law is written for inclement weather driving. There should be other laws written in regards for speeding in certain zones and maximum speeds for reckless. If the speed limit is 55 or even 65 and you're obviously pulling away from the officer then he can even get you for "fail to obey posted highway sign", not even for speeding.
posted by Weeman at 1:03 PM on January 4, 2006

TicketAssassin.com seems like the best option, as mentioned above.
posted by frogan at 1:06 PM on January 4, 2006

Also the officer did not write in his Patrol Vehicle unit number on my citation, without which there is no way to verify the accuracy of his speedometer, and no way to accurately gauge my speed as a result.)

and

If the cop had done his due diligence and wrote his radar number and/or cruiser number on the citation I might not have such a problem with it.

Instead he wrote "Passed CHP" which is not a crime.

I am most definitely not a lawyer, and I'm in New York, but I do know that I got out of a lot of tickets because the cop was lazy in writing them out. You may be able to argue that since he didn't enter his unit # or the citation number then the ticket isn't valid. If the ticket isn't valid then there is nothing for you to defend against and indeed you shouldn't since defending yourself means you accept the validity of the ticket.

Rules vary form state to state and in CA everything you describe may be A-OK. I just know that I've used the invalid ticket defense in New York innumerable times to get out of speeding and parking tickets. Cops are wise to that in New York so they are writing better tickets, but you never know in your case.
posted by xetere at 1:07 PM on January 4, 2006

However, if the there are other records available that says which car the cop was driving that day, lack of a unit number is meaningless.

My day-in-court experience is different from others here. The cop DID show up to do several cases in a row, he did NOT testify*, and hardly any* of the defendants were sworn in. This was in Michigan and pretty much everyone pleaded "Guilty with an Explanation", gave the judge the sob story and the judge threw out the case with the fine paid as court fees.

*The one exception to this was a woman who claimed should was sure she wasn't going as fast as the ticket stated. The judge asked if she was pleading Not Guilty and she said Yes. From there, he swore in the defendant, asked her several questions to which she replied with obvious uncertainty, then swore in the cop who had all his ducks in a row with respect to equipment calibration, training certifications on the equipment, etc. The judge found guilty, then kindly told the woman to hang around at the end of the hour and he would tell her how to appeal.

In my case, I got off scott-free in that case because it turned out the cop knew my neighbor who was also a cop and he recommended dismissal to the judge before I had a chance to say anything.

In other cases, I either paid the fine and took the hit on insurance (which wasn't *that* bad in my case), or went to traffic school.
posted by Doohickie at 1:21 PM on January 4, 2006

CVC 22350, states: "No person shall drive a vehicle upon a highway at a speed greater than is reasonable or prudent having due regard for weather, visibility, the traffic on, and the surface and width of the highway, and in no event at a speed which endangers the safety of persons or property."

the basic speed law does not entitle you to drive as fast as you want as long as you deem it reasonable or prudent. it means that you are supposed to slow down if conditions warrant it.

and anyway, if you are such a stickler for the law, see the previous section of the CVC, 22348: "(a) Notwithstanding subdivision (b) of Section 22351, a person shall not drive a vehicle upon a highway with a speed limit established pursuant to Section 22349 or 22356 at a speed greater than that speed limit."

you admit you were going faster than the posted speed limit. what principle exactly is it that you're trying to adhere to? the principle of i-should-not-have-to-follow-the-rules-like-everyone-else?

contest the ticket and hope to win on a technicality if you want, but don't effect some pompous attitude and swagger around talking about principle. it was a matter of principle when martin luther king went to jail. it was a matter of principle when conscientous objectors burned their draft cards. this? you were speeding and you got caught. don't be a jerk.

there's your lecture. you were fine until you started acting entitled to get off the hook.
posted by sergeant sandwich at 4:56 PM on January 4, 2006

Hey, he may not be any MLK, but a large number of speed laws are made simply to make the government more money. On an open stretch of 4 lane limited-access highway, I see no moral obligation to obey an artificially low speed limit, especially when 90% of people exceed it. Aside from violating the poster's constraints (which is a common, though unwelcome, thing here), these sanctimonious "universe juju" lectures are BS. Get in the right lane and get over it.

Now, my own lecture aside, I can't really give math insight into this problem, but as some people said above, that's probably not the direction you want to head, as you're close to admitting guilt. Your best bet (IANAL or familiar with California speed laws; I know a little about Georgia) is to argue that without a car number, there is no evidence at all that you were speeding. If he said you passed him, and his speedometer was at the speed limit, he can't prove his 65 = real 65 without calibration records. Without the car number, you can't get those records; motion to dismiss since the cop essentially prevented you from doing your "discovery" process.

The likely response is that he's been trained to identify how fast someone is going. I don't know Calif. law, but speeding trials aren't always on "preponderance of the evidence." If Calif. treats speeding as a crime, you have a right to have the case proven "beyond a reasonable doubt". You have to introduce reasonable doubt. The best way to do that, I think, would be to somehow get the cop to admit on cross that his determination of your speed was somehow, some way based on how fast he believed he was going. Meaning he's relying on his speedometer, which we have no proof wasn't broken. You should win, or have a solid appeal basis.

That's my rough sketch of what I would do, based on a good bit that I've read after being in a similar situation. TicketAssassin or other "speeding ticket killer" systems would have more info, some better than others. Google around. And good luck. Hopefully your judge will have more respect for a defendant's rights than others here.
posted by SuperNova at 6:19 PM on January 4, 2006

INAL, but California treats speeding below the level of reckless endangerment as a misdemeanor, SuperNova, and preponderance is fine.

Don't listen to SuperNova. He's as much of a swaggering ass as you were trying to be, finned. :-P The biggest thing that cops and judges like is when someone takes responsibility for something they did. They're more likely to be sympathetic if you do, because that's the lesson they want you to learn.
posted by SpecialK at 2:22 AM on January 5, 2006

You'd think all the sanctimonious people in this thread lecturing the questioner would not break the rules of Askme by not only not answering the question, but polluting the thread with shit that the Finned specified he didn't want to hear.

And yes I know I'm not following the rules either, but i am for breaking the law.

Finned if you contest this ticket at all it will probably be thrown out since it looks like it was sloppily written. If you don't want to pay the fine whatever you do, do not take responsibility for your own actions.
posted by afu at 6:12 AM on January 5, 2006

One thing to keep in mind: Cops will lie on the stand and there's nothing you can do, Perry Mason.
posted by klangklangston at 11:47 AM on January 5, 2006

swaggering ass

I'm totally writing that down for my new sockpuppet. Thanks, SpecialK!

Aside from that, well, that sucks about preponderance. Travesty, if you ask me. But look into the internets for some good info on beating it. At worst, you'll end up paying the fine and being glad you tried.
posted by SuperNova at 3:55 PM on January 5, 2006

afu: i did answer the question. meh.
posted by sergeant sandwich at 1:49 PM on January 6, 2006