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Radar Beats GPS In Court — Or Does It?
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."
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.
Have you considered driving 3mph slower? It seems that they really mean it when they post the speed limits in your area.
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.
The margin of error is for your speedometer, not for you to knowingly drive over the limit.
(tolerance is 3% here in Victoria, Australia);
http://michaelsmith.id.au
'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.
These posts express my own personal views, not those of my employer
You can do that, but then you could also get nailed with careless or wreckless driving....
Wreckless driving usually gets you in less trouble than the alternative...
Reckless. </pedant>
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.
You just got troll'd!
I think there should be an offense known as "frivolous citation"
A cop knowingly writing a bogus ticket should get a huge fine of their own.
Too bad the cities that rely on ticket revenue won't bite.
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)
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.
This article has important details about why the commissioner believes the GPS data supports the ticket.
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.
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.
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?