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## Radar Beats GPS In Court — Or Does It?369

TechnologyResource writes "More than two years ago in California, a police officer wrote Shaun Malone a ticket for going 62mph in a 45-mph zone. Malone was ordered to pay a \$190 fine, but his parents appealed the decision, saying data from a GPS tracking system they installed in his car to monitor his driving proved he was not speeding. What ensued was the longest court battle over a speeding ticket in Sonoma county history. The case also represented the first time anyone locally had tried to beat a ticket using GPS. The teen's GPS pegged the car at 45 mph in virtually the same location. At issue was the distance from the stoplight — site of the first GPS 'ping' that showed Malone stopped — to the second ping 30 seconds later, when he was going 45 mph. Last week, Commissioner Carla Bonilla ruled the GPS data confirmed the prosecution's contention that Malone had to have exceeded the speed limit and would have to pay the \$190 fine. 'This case ensures that other law enforcement agencies throughout the state aren't going to have to fight a case like this where GPS is used to cast doubt on radar,' said Sgt. Ken Savano, who oversees the traffic division. However, Commissioner Bonilla noted the accuracy of the GPS system was not challenged by either side in the dispute, but rather they had different interpretations of the data. Bonilla ruled the GPS data confirmed the prosecution's contention that Malone had to have exceeded the speed limit."
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## Radar Beats GPS In Court — Or Does It?

• #### Standard Calculus (Score:5, Insightful)

on Saturday November 07, 2009 @05:29AM (#30013290)
If the average speed is 45 mph, and he was stopped at the end (ie speed 0), then at some point he was going above 45. Especially since you can't stop instantaneously. This is like calculus you learn in High School... If the Judge ruled the other way, the future of America would be even in deeper sh*t than it already is.
• #### Re: (Score:3, Informative)

Seconded. Furthermore, even if the GPS averaged on a much smaller interval, quoting http://www.pressdemocrat.com/article/20081206/NEWS/812060371/1334/NEWS [pressdemocrat.com]:
"The distance between the radar reading and when he was recorded going 45 mph is great enough that Malone could have easily slowed down, Heppe testified."
Game over son, you lost.

• #### Re: (Score:3, Interesting)

It will make an excellent word problem in class.

Kids might even pay attention to this one. ;)

• #### Re:Standard Calculus (Score:5, Informative)

on Saturday November 07, 2009 @05:45AM (#30013342)
The problem of this calculus you mention wasnt the speed at the end, nor even the beginning. we're missing a piece of information to properly go through this. distance. it says at a stop light, he was 0, then the next ping was 45. but the problem becomes distance covered in that 30 seconds. tie in the math, etc. if it says 45 on the ping, thats worthless. we need to know how far he traveled in 35 seconds to get an average speed, and, for the sake of argument, his vehicles 0-60 speed as well to get the stats on how quickly he could have possibly gone up to 60, nearly where they "clocked" him. obviously, his average speeds worthless, and his speed 30 seconds after his initial of 0 is worthless. we need the distance traveled in that 30 seconds. And TFA says "virtually" the same location. For all we know, he spotted the cop, hit his brakes and was doing 45 when he was pinged. Distance is key ... notice how TFA forgets that wonderful detail. And, I'm sure as a teenager, with a GPS, he knew that if he hit 70, theyd get an email alert. Heck, he probably knew that if he wanted to, he could go 69, wait for a ping, if he had timed them right, speed up to 100 and brake to 69 again, all before the second ping... I guess the parents forgot that Teenager + Technology is generally > Parents + technology
• #### Re:Standard Calculus (Score:4, Informative)

by Anonymous Coward on Saturday November 07, 2009 @05:56AM (#30013392)

"It recorded Malone sitting at a stoplight at Frates Road and 30 seconds later going 45 mph 2,040 feet farther down the road, according to Heppe."

d=rt so we have 2040 = x * 30 so 2040/30 = x x=68!

Yep - GPS proves he was speeding.

• #### Re: (Score:3, Informative)

i only caught the part on the pressdemocrat link. missed a whole other link :D take one thing into account now, the rough 0-60 speed of a car, that can do 0-60 in 6.8 seconds. it would travel around 300 ft if the speed was exactly the same the whole distance to 60. thats the other part we need in this equation and we're golden. if it took him 300 ft to get to 60 at 6.8 seconds. he has 23.2 seconds to continue 1700 ft. so he'd of been doing, 73 :D now figure in his car was really slower then that, but 65 wo
• #### Re: (Score:2)

6.8 seconds? When did they start giving kids fast cars? The Ford Escort I had at 18 would probably get there in... ooh, 16 seconds, if I pushed it. Probably don't make cars that slow any more, but even so.

• #### Re: (Score:2)

When did they start giving kids fast cars?

If the parents can afford to buy the tracking equipment and fight the ticket in court, they have plenty of money and time to lavish on junior.

The Ford Escort I had at 18...

Still cooler than taking the yellow bus to school.

• #### Re: (Score:3, Interesting)

As best I can tell, it started around 2000. When I graduated in the mid 90s, we all had shit cars. When I started teaching at a poor, rural HS (20 miles down the road!) in 2004, kids had all sorts of ridiculous cars. Vintage 60s cars, totally refurbished. Cadillacs, Audis, jacked up trucks with dual smokestack exhausts, pink mustang, etc. The "normal" kids all had newer hondas and toyotas. A good chunk of the student body had a better car than I did.

Apparently, in the last generation, parents lost

• #### Re:Standard Calculus (Score:5, Insightful)

on Saturday November 07, 2009 @11:42AM (#30014766)

unless mommy and daddy paid a load of cash to make it go faster

Let's see...
*His parents installed GPS to report his speed every 30 seconds and download the data to their computer.
*If he hit 70 mph it would send his parents an email.
*He was on his way to the Infineon Raceway, which on July 4, 2007 was hosting the Independence Day Bracket Drags [infineonraceway.com], which is an amature/pro drag racing event that included a "High School" category.

You don't have to be Columbo to figure out that this kid probably had a propensity to burn some rubber at a stoplight.

• #### Re: (Score:3, Interesting)

It was also the wrong place to try this stunt. It seems as if a lot of people from the 60s(read hippies) decided to settle in this area and have families. And the area is known for having thousands of small self-run businesses as well as being home to HP's Northern California operations. The average level of adult education in that county as a result is almost a Masters. There just are no idiots or stupid judges, either, to be found. I'm completely not surprised that the judge knew basic Calculus and

• #### Re:Standard Calculus (Score:5, Informative)

on Saturday November 07, 2009 @06:06AM (#30013440)

Actually, you did your math wrong. 2040 feet / 30 seconds = 46.4 miles per hour.

The thing is, that's the average speed over the 2040 feet. As was mentioned above, given the initial condition of v(0) = 0, this means that at some point in the intervening distance, the kid must have been going significantly more than 45 mph.

The final condition of v(30 seconds) = 45 mph would increase the peak speed even more.

• #### Re: (Score:2)

Uh?

2040 over 30 is 68!

I'm sure I'm missing something here.

• #### Re:Standard Calculus (Score:5, Informative)

on Saturday November 07, 2009 @06:57AM (#30013600) Homepage

2040 over 30 is 68! I'm sure I'm missing something here.

Yes, he is converting from feet over seconds to mph at the same time.

• #### Re:Standard Calculus (Score:5, Funny)

on Saturday November 07, 2009 @07:52AM (#30013792)

Yes, he is converting from feet over seconds to mph at the same time.

Look, do you want the rigorous NASA method or not?

• #### Re: (Score:2, Informative)

by Anonymous Coward

2040 ft / 30 seconds != 68 miles/hr. it equals 68 feet/second, which is 46.36 mph. Still speeding though since he was stopped at the beginning, so he couldn't have been maintaining that 46mph the entire time and would have to have gone faster than that. 46 mph is still speeding anyway ;)

• #### Re: (Score:2, Funny)

You missed the fact that the 68 is in feet per second. 68ft/1sec * 1mile/5280 * 60sec/1min * 60min/1hr = 46.4 Mile/Hr Come one, that's just standard unit conversion.
• #### Re: (Score:2)

Ah! See, I told you I was missing something :-)

• #### Re: (Score:2)

Rough calculations suggest at most 52 MPH. That's assuming that from stopped, he accelerated to his max speed in about 6 seconds, then decelerated to 45 in time for the last 1 second interval.

While that is over the speed limit, it's significantly less than 62 MPH.

• #### Re: (Score:2)

Well, he had around 30 seconds to reach his peak speed and decelerate, so he had ample time to go considerably faster than 52 before he started slowing down.

• #### Re: (Score:3, Informative)

You state that you ASSUME he accelerated in only 6 seconds, and decelerated in only 1. These are feasible, and maybe even likely.

You also assume that he started accelerating at the same instant as the first reading and decelerated only in the last second. While still possible, this is extremely unlikely.

It's interesting to me that despite these assumptions, you still say "at most 52 MPH." It would actually be much more accurate to say "at least 52 MPH, but probably more."

• #### Re: (Score:2)

What we really need to know is the rough rate of acceleration on the car. The higher the rate of change in v, the lower the v.max must necessarily be.

• #### Re: (Score:2)

What i find strange is that there is only an average recorded speed. My gps can tell me my speed at the exact moment, so if i would record that , it would show my speed , exactly over time . Then you would also be able to see where i stopped , and when exactly when i speeded. So it would be much more acurate then a radar.

So , bad GPS tracking system.

• #### Re:Standard Calculus (Score:5, Informative)

on Saturday November 07, 2009 @06:00AM (#30013406)

My gps can tell me my speed at the exact moment

No, it does not. GPS only tells you your average speed between two GPS pings. Ping 1 - you are at X, ping 2 - you are at Y, your current speed is how fast you must move in order to get from X to Y in time between ping1 and ping2.

• #### Re: (Score:3, Informative)

yes , well , then these pings are very close together , because it near exactly matches the speed my car is going .
Offcourse , it may be off by some , but the same is true for the radar.

If i went 62mph , at a given time , i would be able to see that on my gps . It won't show as 45mph.

• #### Re: (Score:2)

I have often the GPS showing me my current speed, and I also have a digital speedometer. I guess that the intervals for updating the current speed are about one second at the speedometer and about 10 seconds at the GPS.

• #### Re: (Score:2)

yes. but when you want to STORE the GPS-data for quite a long while, you'd reduce the recording interval

• #### Re: (Score:3, Informative)

Actually that depends on the GPS. Mine updates the speed and heading information every second but stores the information only every 15 seconds. So each saved record contains the average speed for the past second, not the average speed of the 15 second interval.

• #### It uses Doppler shift (Score:5, Informative)

on Saturday November 07, 2009 @07:25AM (#30013692)

A GPS typically calculates velocity from Doppler shift of the D-band signal. This give higher accuracy since the position reading is somewhat unreliable. It also means you can (in principle) get the velocity information virtually instantaneously without having to sample two locations. However, in reality a lot of averaging and filtering is going on, and I think many receivers weighs in both position deltas and Doppler shift in the equations, so the reading is going to have at least some lag.

(Reference [aprs.net])

• #### Re:It uses Doppler shift (Score:5, Informative)

on Saturday November 07, 2009 @12:31PM (#30015158)
I worked on a low cost military training system that used some older civilian GPS hardware. Our GPS's provided instantaneous velocity at 1Hz and instantaneous position at 1Hz. The velocity tended to be much better than the position in noisy GPS conditions. You can also use the velocity to kalman filter the position leading to increased position accuracy. It's hard to tell what a GPS is displaying but internally, the velocity measurement is very accurate but at too low a time resolution for some situations involving moving vehicles. If the GPS in the article was logging at 30 second intervals, it would be very difficult to know anything about the instantaneous speed of the vehicle in question. That my \$.02
• #### Re: (Score:2)

A lot of GPS devices now include an accelerometer, which gives better local accuracy. This can give (quite) accurate information about the current speed.
• #### Re: (Score:3, Informative)

The real answer here is it depends a great deal on the GPS itself, then it depends on how whatever software is reporting and logging this information post processes it.

GPS itself is capable of reporting an instantaneous velocity vector calculated by measuring the doppler shift from each satellite. (Comes in as a GPVTG sentence in the NMEA data) So if the receiver is tracking a lot of satellites with a good distribution and there isnt a lot of multipath problems, the accuracy of this vector is ridiculously g

• #### Re: (Score:2)

Well , neither can the radar.

• #### Re:Standard Calculus (Score:5, Funny)

on Saturday November 07, 2009 @08:28AM (#30013920) Homepage

You idiot, the uncertainty principle only kicks in when objects are small enough to be dominated by quantum effects.

Like a European car...

• #### Re:Standard Calculus (Score:5, Informative)

on Saturday November 07, 2009 @08:29AM (#30013926)

You're screwing up the part of the Uncertainty principle that most people do. It's not position v. velocity accuracy, but position v momentum. For most large things like planets, cars, insects, and protozoa the mass part of the momentum calculation can drive the accuracy error of measuring both down to about zero. The Uncertainty principle only really matters for really small things like molecules, atoms, and quarks where the mass doesn't overwhelm the equation.

Think about it this way in normal everyday life we're not losing a car because it has a speedometer or the Earth because some one is keeping track of a year. For things like traffic tickets the accuracy of both speed and position are extremely accurate.

• #### Re: (Score:2)

What i find strange is that there is only an average recorded speed. My gps can tell me my speed at the exact moment, so if i would record that , it would show my speed , exactly over time . Then you would also be able to see where i stopped , and when exactly when i speeded. So it would be much more acurate then a radar.

So , bad GPS tracking system.

No, it can't. Law of physics dude, not unless you have a GPS based on 'funny action at a distance' quantum mechanics star-trek hocus pocus.

• #### Re: (Score:2)

Yes , i know , poor choice of words.

• #### Re:Standard Calculus (Score:5, Insightful)

on Saturday November 07, 2009 @07:12AM (#30013652)

If the average speed is 45 mph, and he was stopped at the end (ie speed 0), then at some point he was going above 45. Especially since you can't stop instantaneously. This is like calculus you learn in High School... If the Judge ruled the other way, the future of America would be even in deeper sh*t than it already is.

Wondering where you got average speed from ?

If you had followed the first link http://tech.slashdot.org/story/08/07/18/0318228/GPS-Tracking-Device-Beats-Radar-Gun-in-Court [slashdot.org] (a bit of effort I know 2 clicks with the mouse) you would have come to the article
with the quote :-

..... Rocky Mountain Tracking device was "very" accurate, to within a couple of meters on location and to within 1 mph on speed. Dr. Heppe also pointed out that the GPS device released instantaneous data, and not data averaged over a distance.

I personally think this article ( http://www.pressdemocrat.com/article/20091104/ARTICLES/911049901/1334/NEWS?tc=autorefresh [pressdemocrat.com]) does not have enough info to make any meaningful decisions from.

• #### Re:Standard Calculus (Score:5, Informative)

on Saturday November 07, 2009 @07:50AM (#30013788)

Wondering where you got average speed from ?

Average speed is easily calculated, based on the statement from this article [pressdemocrat.com]:

"It recorded Malone sitting at a stoplight at Frates Road and 30 seconds later going 45 mph 2,040 feet farther down the road,"

That would be 2040 ft / 30 sec === 0.386 mi / 0.0833 hr = 46.4 MPH

I personally think this article does not have enough info to make any meaningful decisions from.

No, but it does provide "related links" to other articles which do provide sufficient detail. He started at 0 MPH, ended at 45 MPH, and averaged 46.4 MPH. That can't be done without exceeding the speed limit of 45 MPH.

• #### Re: (Score:3, Informative)

Most of these tracking units are calculating speed in "near real time" based on GPS readings every second or so, and are pretty accurate. The ones that TRACK your speed, like the one the kid had, send the current speed and position in a "ping" every 30 seconds.

So, in all likelihood, the data was accurate for the time it was sent - it wasn't an average over 30 seconds, it was a snapshot of an accurate speed every 30 seconds.

However, this proves nothing, since he was at zero at the light, 45 a half minute la

• #### Only shows how stupid lawyers and lawsuits are (Score:2)

Since he did not take money for this. It sounds like he was trying to prove something. However, even without math AND the fact that the time interval was so long (30 seconds is a long time), it should be obvious that he was clearly speeding. If average is 45 and he started from a stop, then at some point he was going much faster than 45.

OTH, if these units get smart, do 5 (possibly 10) second intervals (still possible to speed a bit and slow down, but not that much), then it would be worthwhile using th
• #### 30 seconds is a low sample rate (Score:2, Informative)

I expect sampling as close to continually as possible would make for a tighter defense, 30 seconds is pretty coarse to predict a spot speed.

• #### Radar Guns... (Score:4, Insightful)

on Saturday November 07, 2009 @05:49AM (#30013360)

Radar Guns aren't completely accurate all of the time. But a 40% increase is far beyond what you might expect from an incurrently calibrated radar guns. The only realistic alternative is hitting a car travelling in the other direction but since police are trained to only use a radar gun on a straight road and at a certain angle that might be unlikely too.

So in this case I would side with the police. Unless they're just flat out lying which I cannot discount.

• #### Re: (Score:2)

Doesn't the angle of the reading effect it as well? How do they deal with that? (or is the effect of this so small as to be insignificant? As well for slopes, it seems like the gun measures a 2d vector, completely ignoring the third vector of the car's motion.

• #### Sgt is an idiot (Score:5, Insightful)

on Saturday November 07, 2009 @06:03AM (#30013422) Journal

'This case ensures that other law enforcement agencies throughout the state aren't going to have to fight a case like this where GPS is used to cast doubt on radar,' said Sgt. Ken Savano,

Well if the summary is true (and I know it might not be), it actually means the opposite since the GPS data was considered at the trial. That means others may try to present their GPS data in future. It certainly doesn't mean that people can't try that defense. There was no precedent set that the GPS data was less reliable than the radar. It's just that the GPS data could be interpretted to be in agreement with the radar data. Also, this is only applicable to one kind of GPS unit under one very limited set of circumstances.

In other words Sgt. Ken Savano is either misrepresenting the whole situation or is incompetent when it comes to the prosecution of speeding violations. Either way he's coming across as dim witted and it raises serious doubts for me about his ability to perform his duties as a police officer, since he can't seem to understand the law.

• #### Re:Sgt is an idiot (Score:5, Interesting)

on Saturday November 07, 2009 @06:15AM (#30013464)

The judge who allowed the case to proceed in the first place is also an idiot. I see no good reason why the case wasn't thrown out immediately.

I can't quite fathom why the court system allowed "So what if the radar said I was going 62 at that point in time. I was going at 45 at two other completely different points in time." as an argument.

I can see how it happened though -
1. Stupid, dishonest, ignorant kid goes home and tells his parents "No, I wasn't speeding".
2. Parents get GPS data readout which shows he was going at 45 "around that time" in two different readings.
3. Parents lack basic knowledge of trigonometry and can't translate the speed over the distance travelled between readings.
4. Neither can the court. Case proceeds.

Seriously though, in every case like this where the defendant (the kid) lies to the court, they should be charged with contempt. If you don't want to lie, take the 5th. It sickens me daily that the majority of our courts time is wasted with dickless wonders who are too scared to accept responsibility for their actions.

• #### Re:Sgt is an idiot (Score:5, Insightful)

by Anonymous Coward on Saturday November 07, 2009 @06:22AM (#30013482)

I fail to see how this has anything to do with trigonometry.

• #### Re: (Score:2)

I think he meant Calculus..

• #### Re:Sgt is an idiot (Score:4, Informative)

on Saturday November 07, 2009 @10:34AM (#30014426)

Algebra would have done just fine in this case.

• #### Re: (Score:2, Insightful)

On further thought, I understand why the judge allowed the case to proceed. In normal circumstances, where it is "cop's word vs perp's word", the cop's authority is sufficient to validate the radar reading. However, as soon as *anything* else is introduced to counter, it becomes (as in this case) "cop's word vs perp & gps". So now you've got to proceed to case to prove that the GPS doesn't disagree with the cop.

Still don't like the kid tho. ;)

• #### Re: (Score:3, Insightful)

The reason is that you need to hear that evidence before you can come to those conclusions.

• #### Re: (Score:2)

That would be perjury, not contempt.

• #### Re: (Score:2)

I'm pretty sure that denying that you committed a crime, even if you did commit it, is not perjury or contempt of anything. Otherwise, everyone who pleads not guilty but is found guilty would be in very big trouble.

• #### Re: (Score:2)

In most cases you get a bigger fine or longer jail time if you are found guilty after a not-guilty plea than if you just plead guilty.
• #### Re: (Score:2)

Correct me if I'm wrong, but GPS doesn't ever report (instantaneous) speed, just location (insert Heisenberg joke here). Given the times of locations, you can calculate average speed. If I travel 60 miles in one hour, I could have gone 60 MPH the whole way, or 100 MPH and then waited at the destination for the remaining 24 minutes. In both cases my average speed would be 60 MPH. I suppose if the GPS locations and times showed that I traveled 60 miles in 30 minutes, resulting in 120 MPH average speed, there'
• #### Re:Sgt is an idiot (Score:4, Informative)

on Saturday November 07, 2009 @11:48AM (#30014800)

Correct me if I'm wrong . . .

You are wrong [gpsinformation.net]

• #### Re: (Score:3, Insightful)

Seriously though, in every case like this where the defendant (the kid) lies to the court, they should be charged with contempt. If you don't want to lie, take the 5th. It sickens me daily that the majority of our courts time is wasted with dickless wonders who are too scared to accept responsibility for their actions.

Sure, but only if Police officers are fired and charged with contempt when they lie under oath. They should be held to a much higher standard.

• #### Re: (Score:2)

...he's coming across as dim witted and it raises serious doubts for me about his ability to perform his duties as a police officer, since he can't seem to understand the law.

What a shame this kid wasn't stopped by one of the vast majority of smart, intelligent, helpful, and caring police officers instead of an ignorant bully boy with a chip on his shoulder.

I'm being sarcastic.

++

• #### Forget the math, you're missing the point here... (Score:2)

This ruling establishes case law from here forward. Her ruling was in favor of the Police and their technology. Lawyers from here forward will stand a snowballs chance in hell of appealing, even if the GPS data is right and the radar gun is wrong. THAT was the point of this ruling, and unfortunately, it smacks of corruption.

Criminal, you might still stand a chance in proving your innocence these days. Civil? You might as well bend over now. Pisses me off.

• #### Re:Forget the math, you're missing the point here. (Score:4, Insightful)

on Saturday November 07, 2009 @07:08AM (#30013640)

No, and allow me to dismiss this as some anti-The Man banter. Radars are standardised, calibrated, designed for the purpose, operated in proper condition by trained operators, etc... The log from someone's GPS is made by the software from some company which won't necessarily disclose how it gathers, processes and stores its data, furthermore those can be imprecise (how many times does your GPS show you as crossing through buildings when you're driving in city centers?), and who's to say that no one tampered with the data (in this case, edit the data in the log to make it seem impossible to have speeded).

So the decision is only common sense. If you really need an analogy, that's as if you provided a court with a written transcript of conversation when they have an audio recording done with their own equipment of the same conversation.

• #### Re: (Score:2)

Agreed,

There is no real data integrity with these devices.

I can get the track log of my GPS, manipulate the data and then shove it back in to the device...

Any good lawyer could get this 'evidence' thrown out.

There's been cases here in Australia where the GPS evidence WAS allowed and they got off the infringment, but I can only assume that the prosecuting lawyers were incompetent and did not pursue the possibility of bad data in the GPS.

Also, the Radar is a certified calibrated instrument,and the GPSr is not

• #### Re: (Score:2)

No, you both missed the point. The accuracy of the GPS unit wasn't challenged in the court, it said so in the summary. The GPS data was found to support the radar gun evidence. Don't feel bad, apparently Sgt Savano also missed the point. If this is the only precedent, then GPS data is still fair game in a courtroom, and disproving it will have to wait for another day.

And to 4D6963, be careful not to confuse the GPS position data with the map data that it overlays to produce the amusingly inaccurate anomal

• #### Re: (Score:2)

Actually radar guns often suffer from not being calibrated or operated correctly. Laser speed guns too.

The main problem is that they need a fairly flat and vertical surface to bounce the radar/laser beam off. Cops usually use the car license plate but their aim has to be pretty good.

The radar in speed cameras is even worse, so bad in fact that here in the UK the radar is not used in a prosecution. Instead they paint lines on the road and take two photos a short time apart to use the distance travelled relat

• #### GPS speed not accurate 100% of the time (Score:2, Interesting)

How the court can even consider comparing stationary technology that operates up to a few hundred meters with something that is 20,000 kilometers away traveling at 14,000 km/h is beyond me. GPS accuracy is effected by builings, mountains, etc.
• #### what's wrong with America (Score:5, Insightful)

on Saturday November 07, 2009 @08:09AM (#30013838) Homepage
Fuck the parents and fuck the kid. A good parent would have told the kid "tough luck, we pay the ticket and you pay us back from your allowance". But noooooooooooo, better to make a fucking mountain out of a grain of sand at taxpayers' expense to prove a point that is questionable to anyone with a basic understanding of calculus and physics.
• #### Re: (Score:3, Insightful)

The parents didn't understand the math involved, you can fault them for that. But if I were in a situation where one of my kids was accused of something and I genuinely believed that they didn't do it (and had what I believed was proof too), then HELL YES they should fight it.

They might be ignorant, but they weren't wrong in a moral sense.

• #### They knew they were guilty the whole time (Score:4, Informative)

on Saturday November 07, 2009 @10:53AM (#30014512) Homepage

The kids dad was the one who fought this the whole time.
The dad got the GPS because of prior infractions by his son.
The kid got 2 other motor-vehicle infractions while this case was proceeding.
Halfway through the case, the dad changed their defense from "The radar gun was wrong", to "It was an illegal speed trap."

They knew they were going to lose the whole time, they just hoped the county wouldn't put out the money.
Example:
They waited until the county had paid the expenses for an expert to come fly cross country and testify. Right before he was to testify, the kids lawyer got a continuation so the expert had to go home and get paid again to come out later.

• #### The actual calculation (Score:3, Insightful)

on Saturday November 07, 2009 @09:31AM (#30014186)

http://www.pressdemocrat.com/article/20081206/NEWS/812060371/1334/NEWS

Apparently, the GPS logs position, time and speed every 30s. Regardless of how the system calculates speed, whether by averaging between each logged point or using much smaller time intervals, the data shows that the car was stopped at some t = 0 and had moved 2,040 ft after 30s. That results in an average of (2040 ft) / (30 s) = 46.36 mph.

Assuming a linear acceleration profile, he would have had to reach a speed of 92.72 mpg to run the 2040 ft in 30 s, but that's an unfair assumption. He was driving a 200 Toyota Celica GTS, which accelerates from 0-60 mph in 6.6s, thus at a maximum he can increase his velocity by 9.1 mph each second (assuming constant acceleration). Thus, the absolute minimal velocity the driver must have reached is 51 mpg, reaching this velocity in 5.6s and maintaining it for the remainder of the path to the next logged point.

The article does not specify where exactly was the police officer read the car's speed, which is crucial to understand if the 62 mpg reading is possible, but the conclusion is that the GPS data by itself does prove that the driver must have been above 45 mpg but does not guarantee that a speed of 62 mph must have been reached.

• #### You can't beat the system (Score:3, Interesting)

<damn.registrars@gmail.com> on Saturday November 07, 2009 @10:21AM (#30014372) Homepage Journal
I was once ticketed for doing 45 in a 30 in a woefully underpowered car. The ticket the cop wrote (which I did not see in full until my day in court) claimed I was 30-40 feet from a stoplight where not only did I stop, but I made a right-hand turn. I had two guys in my car with me, which didn't help the car accelerating on flat ground (this was a very flat area of a very flat state). So basically for the ticket to be correct, this car which made around 70hp on a good day needed to be accelerating at Porsche speed while turning.

The ticket that the officer gave me that day (which was missing some of the critical information such as the location where he claimed I was) had a court date on it, so I went to court armed with information on how I could not possibly have been going as fast as claimed.

Instead I was greeted by a DA for that county. I had the option to come back later to be heard by the judge, but the county was quite a ways away from home and I didn't really want to go back. The DA offered me a "plea bargain" since I had no tickets on my record prior. They said I could enter a plea of "guilty not accepted", under which they would accept a lesser fine from me than the original ticket (the DA essentially changed the reported speed from 45 to 38, still in a 30), and as long as I was not pulled over in their county again for the next 12 months the ticket would not be reported to my insurance company (I was a young man at the time so that part was important to me).

I accepted that deal, wrote them a check that day, and I haven't returned to that county since.
• #### radar accuracy coverup (Score:5, Interesting)

on Saturday November 07, 2009 @10:57AM (#30014526)

I think theres a massive cover-up about the accuracy of radar guns. I think the cops and courts all know it but its a massive income generator so they wont do anything about it.

I got stopped by a cop with radar claiming he detected me doing 85 in a 65mph limit. He even showed me 85 on the radar. It was rush hour and the freeway was bumper to bumper stop-go traffic and there was no way I ever got over about 45. I was also surrounded with other cars so I have no idea how he could single me out with a radar. My wife was in the car too and told him I couldn't have been speeding but he didnt believe her either. I went to court to fight it and they made a deal before my case got heard to reduce the speed down to 78 but I still had to pay a fine. It seems to me they wouldnt have done a deal if they thought the radar was truly accurate.

It seems everyone fights based on the accuracy of the radar, but I haven't ever herad of anyone the lack of evidence that the cop was actually pointing the radar at your car and not someone elses?

We can found no scientific discipline, nor a healthy profession on the technical mistakes of the Department of Defense and IBM. -- Edsger Dijkstra

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