My step-son Shaun received a speeding ticket based on Radar. The Officer stated that Shaun was traveling at 62 MPH in a 45 MPH speed zone. The GPS tracker installed in Shaun’s car recorded his speed at 45 MPH at nearly the identical spot the Police Officer noted Shaun was speeding on the citation. Shaun did not believe he was speeding and the GPS verified his speed was indeed 45 MPH at that location. In addition, the GPS tracker noted his speed at several locations prior to where he was cited, all at or under the speed limit. I had told Shaun at the time we installed the GPS tracker that if he was ever cited for speed and the GPS tracker records differed with the citation, that I would go to court and defend him. At the time he wasn’t very impressed commenting “that’s not why you’re putting it in”. He was right, but I will keep to my word. Thus began the Radar versus GPS saga.
I knew that if I let the media know about what had happened, they would find a story there. I recognized this as an opportunity to increase the awareness among the parents of teen drivers of the availability and affordability of using a GPS tracker to keep their young drivers safe. So, I let reporter Derek Moore of the Santa Rosa Press Democrat know about it and the story has gone international. Several reporters who contacted me wanted to be notified when the Court came out with a ruling. Shaun had the option of requesting a trial by affidavit or a hearing. Since we had documentation of the GPS records, we decided to pursue a trial by affidavit. If Shaun lost at that level, he still had the option of requesting a hearing. We felt that the evidence we submitted was sufficient to provide for a “reasonable doubt” as to the charge of Shaun speeding. We did not want to generate the inconvenience of a hearing, for us the Court or the Police Officer, unless we needed to.
Shaun received the ruling from the trail by affidavit. The Court found him “guilty”. We are in the process of requesting a trial by hearing. This will necessitate also requesting “discovery” in order to have access to the police records that could have any relevancy to Shaun’s case. In addition, Brad Borst, the President of Rocky Mountain Tracking, (the company that we purchased the GPS tracker through) has offered to have his top technician testify as an expert witness in GPS, should we need him. I have spoken with Petaluma Police Chief Steve Hood. I know Chief Hood from working with him professionally. I wanted to let him know that we have the utmost respect for the Petaluma Police Department, including the Officer that cited Shaun. I know that attention from the media can be uncomfortable at best, so I wanted to let him know that we will continue to contest the citation. Further, I would continue to work with the media to get out the message to parents of using GPS tracking to monitor teen driving behavior.
Ours is a quest for truth in this specific incident, but more importantly, Shaun’s Mother and I want to see a significant decline in the number of unnecessary teen tragedies due accidents. Parents installing GPS tracking devices in their teen’s cars, setting clear rules, and then holding them appropriately accountable can significantly reduce the odds that their teen will be injured or killed in a speed related traffic accident. There is a host of other benefits to using this parenting tactic; this is just the most significant.
Do me a favor. Go thru your sons GPS records and see how many times it shows him rolling thru stop signs.
These tracking devices log and average data, so I can guarantee you that you will have ‘proof’ that he is running stop signs.
Of course you have your own agenda so you’ll cherry pick the data points to disprove me, but I don’t care.
Well Paul, the GPS will not show if the car has “rolled” through a stop sign. It reports the car’s speed, location, direction of travel, date and time at the moment the unit “pings” that information to an on-line data base. That is where I view the data. It sends a “ping” every 30 seconds. You can do the math between the points where the GPS “pinged” to get an average speed between the pings.
I have no need to “cherry pick” data. It is what it is, and if it shows that Shaun has violated the standards that have been set for his driving, then he will be held accountable (as he has been). My agenda is to keep Shaun safe and help him develop appropriate driving habits. I hope other parents do the same with their teens.
I live in a world where it is possible for two people to be right at the same time.
It sounds like the GPS unit is sampling fast enough and the company should be able to provide data that what it claims is true. The radar unit probably read what the officer said but there are a lot a variables to consider. I’m sure the facts will come out if enough data is collected. This is an important case and I hope you can hang in there to see it out.
Good Luck,
Sarge
“You can do the math between points….”
OK, so if my GPS plots a point every 30 seconds and I have a fast car:
Start at 0 MPH
Get up to 70MPH
Come to a complete stop and the GPS will show my ’speed’ as 35MPH or even less if I didn’t use the complete 30 second window.
Thanks for proving that your GPS isn’t an accurate indicator of time at a specific instant in time, unlike a radar gun.
Roger, I back your fight 100%. I surely agree with your stated reasons of teen safety, but I wish to go one step further which I’ll pose with a question. How can any judge or law enforcement person argue effectively against your evidence when they (law enforcement) use electronic devices to their end in every instance? Is it not hypocrisy to say only their equipment works? Keep up the good fight!!
I’m just wondering how much of the tax payers money are you all willing to waste on this? Its real irritating to spend 12 + hours at work and have a good chunk of my hard earned money pulled out of my check and wasted on the legal system to deal with this crap!! This is a joke. Maybe I should file suit for you all being jackasses and stealing my money.
Another question people should be asking in this thread is “how accurate is radar?” My answer is that radar is very accurate; it is just not vehicle specific. There is a reason that many law enforcement agencies are turning to “Lidar” which is laser based technology. That reason is to close the gap of misidentifying what it is that is generating the indicated speed on the radar unit.
I am not out to spend tax dollars on this issue, nor am I responsible for how much money an agency chooses to spend and on what. I, personally, would rather see that money invested in laser based technology for traffic enforcement so there would be fewer chances of tickets being issued in error. My hope was that this issue would have been settled at a trial by affidavit, with no further expenditure of public funds. However, I certainly disagree with the idea that anyone should plead “guilty” to anything that they are not guilty of doing.
As to thoughts that others who wear the badge disagree with what I am doing, I will just say that I have always tried to plot my direction by a compass and not a popularity weather vane. I respect anyone’s right to disagree with me, as is evident by the comments I have approved and posted. Debate is what this country was founded on. My greatest satisfaction is the exposure this is giving to a wonderful tool for parents that can make a big difference in the safety of their teens.
As to sending a wrong message to teens… I don’t buy that for a moment. The message is, don’t speed, be safe. The other message is: Don’t be afraid to take a stand for justice, regardless of where it takes you. What message would it communicate to Shaun if we instead said… you are not guilty, but plead guilty, take the path of least resistance? Or, even worse, not support Shaun when he is innocent of an allegation made against him? We are talking character and ethics.
For those of you that think that Shaun was speeding and is guilty, I disagree. I have done my own investigation into this and I would never defend Shuan if I thought he was guilty. It would have been a lot easier for me to not have engaged in this fight, but for the very same reasons I became a cop, I will continue to support Shaun in this matter. It is called justice. If you, or someone you loved, were mistakenly ticketed would you do less?
While I give your son the benefit of a doubt – a ping every 30 seconds seems grossly insufficient to plot an accurate reflection of speed. It is a 30 second average – which based on the specs of my vehicle, can include a lot of fast/stop/slow driving.
Using my vehicle ratings – it can accelerate to 60 MPH in 7.2 seconds. It can cover a quarter mile in 15.4 seconds, achieving 89.6 MPH. As well – braking to a complete stop from 60 MPH can be achieved in less than 118 feet.
Just seems there is a lot of room for speed variation in an average based on a 30 second interval.
I say support your son but not carry his battle for him. He also needs to learn that sometimes life is just not fair either. It this case your ignorance of GPS and getting in bed with a company who’s interest is selling a product, albet a useful one, is clouding your judgement. It is well within your right to fight this battle but what you are actually teaching your son is that he can always fall back on dad when things go wrong in his life. Any thought that your son has been able to “game” the system to get around your big brother monitoring? Any self respecting and intelligent teen would find ways around this – especially your son who was adamantly against it from the beginning.
Hi Roger
I spent ten years of my career involved in the development of GPS-based vehicle tracking systems, first for Trimble Navigation and then for Nextbus information systems. There is no doubt to anyone with adequate scientific training that a properly designed GPS system is far more accurate than radar.
While GPS may be proven to be accurate in tracking speed you’ve got a big uphill battle to deal with. That battle would be the accuracy of the software and the company that’s actually logging that data. It’s going to depend on your update interval and conditions that were present at the time of the incident. Unless you have a update event that’s mapped at the exact point where the radar was done you have no real way of proving your son wasn’t speeding. The update point could show just before the incident that he was doing the limit and it could show that after the incident he was doing the limit. You should be able to see on the reporting map the exact place that the officer stopped him and see how many real samples were taken prior to him stopping. GPS is accurate.. the reporting by a third party company on an exact date, time and exact location that the radar was clocked his highly unlikely to be accurate.
By the way.. as you yourself said.. it can’t show that the vehicle rolled through a stop sign. Why? Because it isn’t that accurate. An officer sitting at the corner though can see that the vehicle rolled through the stop sign but your GPS may show that you blew through it at the speed limit because of the sample rate. I like Paul’s comments as well. What if your son stomped on it through a small stretch of the road that just happened to be where the officer had his radar setup. GPS will guarenteed not show that short stretch where it was stomped on. I’ve done it myself with my GPS and there’s lag. Never registered what my top speed was although I new how fast I hit.
Oh and one last thing.. as a former cop yourself what would you think if you were the cop with the radar gun that you knew was in perfect working order and was accurate and some one took an unproven an not recognized technology that already is known to have accuracy “issues” and took you to court? I think what you’re teaching your son is that there isn’t a respect for law enforcement despite your former position. It sounds to me as well that you don’t trust the accuracy of the radar gun which I’m sure you’ve used many in your years as a cop. Let’s all go out and buy our own independant speed tracking systems and fight every radar ticket out there because radar isn’t telling the truth about our driving.
Yes I would fight for a loved one if they were wrongly accused of something. However fight the radar and whether that radar gun was in proper working order. If it was then you’ve lost your case. Don’t try and prove your son’s innocents by using your own independantly installed speed tracker that’s not 100%. It’s like the guy that robs a bank and is on video then says he wasn’t guilty and didn’t do it… come on. Show some real respect for law enforcement out there.
Some of the comments above are just technically wrong. First, the most accurate element in the content of the GPS “ping” message is the time. The atomic clocks on the satellites are accurate to within 100 nanoseconds. Most receivers round this to within a microsecond. Second, the velocity reading is instantaneous, not done by averaging. Third, with a 30 second update rate and a normal street car it would be extremely to time accurately enough to go from 45 mph to 62 mph and back down to 45 mph between pings. Fourth, while a 30 second update system could not verify stop sign behavior, that is not because of an inherent inaccuracy in the technology. A system with a 2 second update could tell if a vehicle rolled through a stop sign.
Jim – the GPS measures speed as a side benefit to its ability to plot location. I’m not disputing it’s ability to do this but in the manner in which it calculates speed. It uses the plots between two locations calculates the distance between them and applies the specific time between samples to arrive at a determination of speed. In essence, it is a virtual speed trap/chronometer like that used to clock bullets and land speed records. It is an average of the speed between these two points. The timing is very accurate but the error occurs in the location plots which can vary up to 15 m in consumer units. With short plots speed errors can increase significantly. It will always be an average speed – sudden acceleration will always show a slower speed than actual and the reverse is also true. Radar on the other hand IS instantaneous – a doppler shift in the reflected signal’s frequency is what determines speed, not a time vs distance approach. The technology is there to make GPS accurate to speed changes but the cost of doing so and the need for it is not there yet for the average consumer. Ping rates would also need to be rapid then data storage becomes an issue. At best GPS calculated speed is only informative at this point – not definitive – at least insofar as challenging the accuracy of radar.
PS: Rude was a deputy sheriff not a traffic cop, chp or city police and has no experience or training in radar or it’s use. If he did this whole thing would not be up for discussion as he would be questioning the officers observations, training and experience in using radar rather than the technology. This is the only area that can be legitimately argued.
Hey Jim Maresca.. you have no clue what you’re talking about and obviously have no experience with GPS and tracking. The 30 second update arguement is extremely valid and extremely inacurate for determining the exact speed of the vehicle unless an assumption is made that the vehicle is maintaining a constant between the two points measured. RVRUDE obviously knows this becuase he himself said “do the math” which is basically taking the speed reading at the point of the first measurement then taking the speed reading at the second point of measurement which is 30 seconds away. If you end up measuring the first point at 45mph and the second point at say 50 mph there’s no way you would know if at some point between point 1 and point 2 that the speed went up to 62 (which is when the radar was read) then back down to 50. The only way you will really be able to tell is what the average speed is between the two points. This can be measured two ways. One using the speed measured at both points… less accurate.. or two using the time stamps of when the two reading were taken and the distance between those two points. Once again though you will only get an average of the speed that was traveled between those two points. You would need a much quicker rate of updating to really determine where the “spikes” in the speed were and at what point in the road those spikes occurred.
While most all consumer mapping GPS devices read the satelite information at 1 second intervals (more than enough to determine the spike).. RVRUDE had his reporting interval set for 30 second which means he loses 28 seconds of data and has a less accurate picture of what really took place between those two time samples.
Easily one could calculate an average speed but was that averaged based on constant travel speed between the two points or was there some low and high points of speed which calculated to the same average. That’s what RVRUDE has to prove in court. Once again it’s not the accuracy of the GPS but more the accuracy of the reporting data that he has that’s only really a sample of the overall trip which doesn’t have the granularity of the data samples needed to prove his case.
By the way.. Kenny makes another good point. With a 15m +/- accuracy on a very clear day and a fantastic lock on multiple satelites the plots for both sample 1 and sample two could make the distance traveled be up to 30m longer or 30m shorter than the actual traveled distance. Not to mention the map being used can change the accuracy as well. Ever take a GPS with the “breadcrumb” feature and turn the feature on then download the trackpoints to Google Earth or Yahoo maps? The results could show that you drove off road more than once and we know that wouldn’t be true now right?
Now add a cloudy day or tree cover and the GPS accuracy can be off by several meters more than just the 15m under optimal conditions. RVRUDE has a very steep hill to climb to prove his case which in my opinion and experience isn’t provable at all.
Sorry multiple postings again.. this one goes directly to RUDEVIEW. After reading a post you did back on 11-25-2007 you said that radar makes mistakes.. GPS doesn’t. I think you had beter do a lot more homework on consumer GPS devices starting with what SA is and why the government turned it off. After researching that take a look at the specs of several consumer GPS devices out there.. especially the ones that don’t have DGPS. You’ll note the specs will say accurate to within +/- 15m under optimal conditions. If GPS doesn’t make errors then why is there a +/- deviation listed in the spec and what if conditions aren’t optimal? And why are google maps, yahoo maps, magellan mapping software and garmin mapping software all not exactly the same? That’s because there are errors in the maps as they aren’t 100% accurate. Who knows what map was used for plotting your report nor how accurate it is. You’ve got a ton of stuff to prove to win this one.
Mr. Rude,
I, like you, also support the law enforcers and the hard work they do to keep our roads safe, but I deeply resent the failure of traffic engineers to place properly determined speed limits on our highways. I read in the PD today that you had requested a “traffic and engineering survey” for the area of the alleged violation on Lakeville highway. My guess, without having seen the report, is that the speed limit was not properly determined. The law is very fair to drivers and it insists that any “prima facie” speed limit (for practical purposes anY limit under 55) requires a substantiating “traffic and engineering survey.” What almost all citizens do not know (and in discussing the subject with attorneys I am finding most of them also do not know) is that the law has been recently changed. It used to require that the speed limit be set at the first 5 mph increment BELOW the 85th percentile derived from the survey of actual speeds. The law now reads that the speed limit must be set to the NEAREST 5 mph increment to the 85th percentile of surveyed speed. My experience has been that the majority of prima facie speed limits do not now conform to the law. I do not know if that is the case in your stepson’s case but it could well be. If the 85th percentile is above 47 mph on the survey, then the limit is improperly determined. There are exceptions that allow for another 5 mph lowering of the limit but they are clearly stated and seldom met. If the limit is improperly set, then the area is a “speed trap” and all radar tickets given are invalid regardless of the speed cited. Good luck!
Dear Sir,
I have been following this story and have some things to add. First of all, I’m a law enforcement officer who has used radar on many, occasions. It works!!! The fact that the officer is required to visually estimate a vehicle’s speed before using the radar has been absent from any discussion thus far. I could go on and on about the radar stuff but…I assume you know most of it.
I’m disappointed in the fact that you are basically thumbing your nose at a fellow law man out there doing his job because of something a machine is telling you on a computer screen. You were not there sir and don’t truly know what happened. Only your step son and the officer are fully aware of all of the details. By asking the courts to rely solely on the accuracy of a machine is setting a scary precedent. Should we then be able to download all information off of GPS’s and use that to ticket people who are speeding…even when a law man isn’t looking???
I live in Petaluma and I hope that the Petaluma Police Department fights this thing, tooth and nail. I can assure you that you are doing nothing but teaching your step son that law enforcement officers can’t be trusted to do their jobs correctly. How about teaching him some responsibility….
Right on Dave! He has no standing in this only his son. As with any contested citation the issue is with the training, experience, and observation of the officer vs the defendant’s story. This is what the judge will weigh in his/her decision. Pieces of paper, not supported by direct testimony are not admissible as evidence in court as Rude should be well aware of. Of course a technicality of a faulty speed survey could render the citation moot as Peter suggests but I figure that issue would have been examined in the initial ruling which found him guilty.
Regardless of the exact details of this case, this boil down to the sample rate of the GPS data.
Far too common is the belief that radar and LIDAR is infallible.
The instrument displays a number and the officer goes with it.
Too many enforcement officers adapt their style, instead of the instruction steps, too time consuming to comply with. Without checks and balances, its his word v. the officers in a preponderance of the “evidence”: A no – win situation.
The attorney should focus on the elements of the situation & scenario, as they apply to the elements of your state’s vehicle code / laws.
Very basic fundamentals should be able to either discredit the radar reading or the certification(s) documentation your state / county requires.
The environment these instruments are used within, influence their calculated readings.
LIDAR is worse than radar in many aspects…….. Depending on the sample rate, I’ll take the GPS w/ a tracking history.
Can you publish the radar make and model?
S u f D a d d y.
The radar unit used in this case was a Genesis handheld “K” directional GHD stationary radar gun manufactured by Decatur Electronics, Inc and sold in December of 2005.
Those of you citing sampling rate for the reason of inaccuracy are actually incorrect. Although the sample rate was set to 30sec what this in fact means is that the GPS unit sent data every 30 seconds to the Internet, not that it was sampling from satelite every 30 seconds (such a sample rate would not be possible as its too slow and would require reacquistion).
The GPS device itself will be sampling around 1 second, but every 30 seconds it will send the reading at that 30 second interval to the Internet server. A sampling rate of 1+ seconds is too slow to show things such as stop sign evasion but for someone driving a long a highway it is perfectly adequate to be within a mph of the true speed.
The article states that the reading used was at virually the same point as where the officer clocked him – that would have been a 1 second distance calculation between two points, not an average of the last 30 seconds.