speed detection devices and methods

Factual Questions
21

Refer to my fourth post. I don’t care what you think about speeding or whether you think I’m “whining”.

In my OP, I was looking for information about the law and the proper operation of the devices used by the police to determine vehicle speed. Why I’m asking is irrelevant.

But if you think giving opinions are more important here, I’ll give you mine.

It happens that I feel a $200 fine is excessive and unjust given the circumstances. If the city of Houston was serious about promoting public safety on the roadways, then they would park a cruiser at every intersection along Westpark, Westheimer, Memorial Drive, Fannin, Little York, Almeda - and every other street in this city where people drive like crazed maniacs - and ticket EVERY SINGLE CAR THAT’S BREAKING THE LAW but charge them no fine. Then once enough tickets are collected by the truly dangerous drivers, they would eventually be removed from the street, and the true goal of public safety would be achieved. Instead, we have cops hiding out in the dark and randomly picking vehicles along undeveloped stretched of highway and handing out these fines in the name of public safety.

In my personal opinion, the lower speed limits in this location do nothing to enhance public safety, rather, they provide an easy place for the police to find and stop drivers who are driving faster than the posted speed limit due their inherent inclination to drive at the “natural and reasonable” speed for that particular road. The state of Texas uses that phrase, not me, - read Section 545 of the Texas Transportation Code.

Yes, the law allows city governments to post any speed limit they want on state roads that’s below the “natural” speed of the roadway, but don’t kid yourself for one second that posting such a low limit is in the name of “safety”. Posting these speed limits and then waiting around for someone to drive faster is revenue enhancement, not public safety. This is a straight 2-mile stretch of roadway with no intersections, driveways, buildings, sidewalks, or entrance ramps to the adjoining interstate. How in the HELL can the police, or you, tell me that the posted speed limit of 35 mph is the safest possible speed? True, the slower you go the safer it gets, but we’re not all going to quit driving are we? (Or aren’t we, John Rush :slight_smile: )

If I truly felt that had been a menace to public safety that night when I got pulled over, then I would not have a problem with all of this right now and I would probably end up paying my fine and walking away. True, I would still want to find a way to avoid the punishment - that’s human nature - but the relative effect on my conscience would be a lot different than the way I feel right now. Instead, I feel I’m being randomly selected for no other reason than I happened to be the one in the back of the group and it was easiest for the cop to pull me over. I don’t think the cop was “picking on me”, but I also don’t think he pulled me over because he saw me as being the greatest threat to public safety.

I also feel like I’m being taken for granted. The city needs money, speeding tickets generate money, most people, like DYoungESQ and Switchback apparently, don’t fight speeding tickets - the city gets a lot of revenue with little cost - ergo the city will try and collect a lot of speeding tickets. I was pulled over because the city expects me to blindly open my wallet and pay for the bloated programs of a sorry-ass mayor who has no agenda except to get reelected and live on the public dole for a few more years. Of course I’m going to fight because I don’t agree with the law. How will the law ever be changed if everyone always goes along with it? Ever heard of John Locke? My case may not be the same as protesting a war or government oppression, but it is an unfair tax and tacit consent is tacit consent.

In my OP, I was looking for some hard facts and information on the methods, procedures, and tools used by the police to enforce these laws. I was not asking to wade through 3 pages of moralizing from people who have no clue as to the situtation or the circumstances involved. I didn’t ask for your opinion on speeding. I didn’t ask for you to forgive me for breaking the law. I didn’t ask whether you think I’m a dirty criminal crybaby.

If you really want to moralize, then go into the MSP forum and preach all you want.

Nickrz, how about closing the thread on this board and moving it to the MSP’s?

22

Ex-cop here. Please hold your vegetables until the end of the performance. In addition to my street and teaching years, I also built and ran one of the USoA’s five national NHTSA RADAR testing labs.

There is a very good reason why he should not have been able to show you your RADAR speed reading, but the reason he gave sounds goofy, though probably true. You probably took the answer “Texas law doesn’t require me to” as “there is a law in Texas that says so”, when in fact he probably means “the law doesn’t address it.”

My professional experience is from Flawda, which isn’t Tejas by a long-shot, but FL was blessed (yes, I mean that) by the famous Miami RADAR trial of the early 80’s, and the principles derived from that are pretty much nationally accepted. I taught quite a few out-of-state officers as well, and significant differences in 1990’s procedure weren’t apparent.

The reason the officer should not have been able to show you your speed reading is that his RADAR gun should not have been capable of this, or at the very least he should not have been using this feature. Why, you ask?

One of the things that came out of the Miami trial was that the speed locking was:

A) worthless or open to abuse, because the cop could himself drive at, say, 80 mph, with the gun pointed out the windshield; lock in the speed; then display that speed to anyone whom he wished to ticket, making the display of the speed as “proof” meaningless (and this applies to your case as well-showing you “51” blinking on the display isn’t proof that you were going 51).

B) Trying to lock the speed actually deters the officer from performing an accurate measurement. Another thing that came out of the Miami trial was that officers were to focused on getting the highest speed locked-in to the display, which is contrary to what they should be doing. In order to get a good, reliable reading, the officer must observe the vehicle and correlate his observation with the display over a period of several seconds. If he simply “snaps” the speed as soon as the vehicle appears at the top of the hill, that is not a reliable reading.

In Florida, DHSMV Rule 15B-3 requires all RADAR guns used in the state to have the locking feature disabled for just this reason (devices with dual readouts are allowed to retain their locking mechanism).

That may be true under some circumstances, but is not a reasonable answer to the question you asked (giving you the benefit of doubt that the conversation went as you described). Locking the reading would prevent him from further verifying your speed by correlating the reading with his observation of your vehicle, but it wouldn’t give a “false” reading. It is true that, all things being equal, a gun will track the fastest target. But all things are seldom equal; factors like distance, vehicle size, and vehicle shape have more an effect on which vehicle gets tracked.

Some rules may not be “law” per se. Some requirements in FL, such as keeping the log and how often the unit is tested, are promulgated (love that word) and published by the DHSMV. Even so, the courts enforce their compliance, because the state statutes make reference to their compliance. Probably a similar situation in Texas.

As to fighting it: I encourage you but offer a warning: in some states (like FL), while your original ticket price may be $150, the court has the option of imposing a higher fine (in FL, this was up to $500). Some judges, seeing you spending the court’s time on a charge which you freely admit to, are inclined to recoup some of the court’s costs. I don’t agree with this approach, though I understand the judges interest in keeping the system from getting clogged; but I think you, the ticket-holder, effectively have a right to ensure that the state can produce a decent case. In order to do so, you’ll need to know the Texas rules (not just statutes) regarding use of RADAR, and be prepared to ask the state at trial about those items.

Judges view technicalities differently. I myself was ticketed after an accident in which I truly believed I was innocent, and that the other party was at fault. FL law requires that the officer who investigates the accident be the one who issues any citations as a result of the accident, but in my case a different officer who arrived at the scene “helped out” by writing the citation. I brought this up at the trial I requested, but the judge blew it off as irrelevant. Your mileage may vary.

23

Upon reading your further explanation of the “continuing” driver re-training, and seeing that the first was not, as I had originally thought, due to speeding, I will withdraw my “carp” comment. :o
As far as the rest of my statement, I stick by it. If there is a general ruling that access roads paralleling highways be limited to X mph, I wouldn’t expect the highway comission or whomever is the determining body, to examine every mile of access road to see if a higher limit could be applied.

FixedBack

“Misers get up early in the morning; and burglars, I am informed, get up the night before.”~~*G.K.Chesterton *

24

First and only time I ever traveled to Houston on business, I flew in and caught a cab to downtown. The cabbie started on some highway cruising at 90, along with everyone else. Next thing I know, a cop came up on the outside lane and passed! Go figure! And this was during the “Energy Crisis”.

25

Oh yeah, it’s mPs… Oops.

Raza, thanks for your insight. That’s the kind of info I was looking for. Naturally, I’m freely admitting to committing the offense here and then I’m going turn around and plead not guilty, but that’s a different story that’s already been addressed.

I’m going to request that a reference to the “no-lock” laws/rules be furnished as part of my discovery request. I had never heard anything about that not being an option, having always been under the impression that those things lock automatically and as a citizen I should have a right to see the evidence against me. But, I ask, if he doesn’t lock the device, how can he be certain he saw a 51 on the display? How can he be 100% sure it wasn’t 31? NBD… Really, my defense won’t hinge on that point.

What I’m more interested in doing is trying to prove that it wasn’t necessarily my car that he was clocking. (Reasonable doubt, after all…) I mean, my interpretation of our conversation was that he was slightly admitting that there is a chance he might pick up the wrong car, right? I mean, I’m behind the two cars on the roadway, traveling next to a freeway, and we’re approaching the cop from behind at night.

Questions Raza:

1.) How do cops normally run their guns when in this position? Is he facing the rear and “aiming” at a set of headlights or is he facing the front of the car and just pointing the gun over his shoulder (as I’ve seen before)? If that’s the case, how can anyone ever be found guilty in court?

2.) Do municipalities have rules or regulations for determining the proper procedure for doing these stops on access roads? How can they guarantee they’re not picking up a car on the freeway? (I would assume these rules MUST exist, so I’m going to request them, too)

26

Hmmm…the thot plickens. Was he moving? If not, I get the impression he was on the side of the access road (the road you were on) facing the same direction as you…true? If so, were there any other cars between you and he whilst you were allegedly travelling at 51mph?

If there were other moving cars betwixt youse, OR if he was on the expressway itself (NOT on the same road as you), then we may be on to something. Can you crank up Windows Paint and give us a crude diagram?

The general procedures would assumedly be spelled out in some form at the state level, such as DMV rules (like FL) or Rules of Procedure, or possibly in the statutes themselves (unlikely and undesirable, because it takes an act of the legislature to get technical details changed).

I would think it would be reasonable to request a copy of the SOP pertaining to RADAR enforcement from the agency that cited you. You might expect to pay a reasonable photocopy fee. If the agency doesn’t have a policy, then that’s one more point in your favor.

I’ll snoop around a bit and see if I can find anything on Texas.

27

No, he was stopped on the right side of the access road, facing forward with all lights off. About 300-400 yards from the intersection where I made my turn.

I was in the right lane - one car in front of me in the left lane, one car in front of me in the right lane. The two cars in front of me were both about 40-50 yards ahead of me.

I can’t remember, but I think there might have been a car next to me in the left lane and I know for sure there was a car behind me in the left lane, kind of like this:

F * | *
R | COP
E |
E |
W ? | J
A * |
Y

I am going to ask for any possible videotapes he might have just to be sure I have my story straight - I don’t want to go in and then see that I’m imagining things. Would it be normal policy for him to be running a tape while he was sitting on the road, or are the cameras off until the stop is made?

28

Oops. Well, you get the idea, I hope.

29

JohnnyHarvard, I’ve done quite a bit of snooping on Texas statutes and can find nothing about RADAR enforcement procedures, or speed measurement procedures in general. The fact that there isn’t anything, not even a reference to “following procedures”, is ammunition in your case. A bit disturbing, too.

You can check NHTSA CPL to see if the RADAR unit used against you is on the list; if it is not, its another thing in your favor.

30

Forgetting the freeway for a moment: you say that the cop was facing forward (away from you); and that there was a car in front of you, in the same lane (IOW, between you and the officer)?

The direction he was facing is not a big issue (normally), because he assumedly had a rear-facing antenna. But if you are saying that there was a car between you and the officer in the same lane as you, AND he was facing forward (either using his mirror or craning his neck around), then I’d say you could make a good argument that:
A) he wasn’t measuring you (if there was a car in your lane in front of you, there is no way the device was reading your speed), and
B) he couldn’t get a good look at anyone due to his position and the circumstances (darkness, etc.).

I tried to find a copy of the NHTSA RADAR Operator Training manual on-line, but no luck. It would have outlined the standard procedures suggested by NHTSA, and while no local agency is obligated to follow them, it would be notable if they chose not to follow NHTSA’s recommendations.

31

In the U.S., the freedom of mobility has long been a given. To me, it’s a natural right. I see speedtraps, random checkpoints, and other restrictions as a regression. How long before we reach the point when we can travel only when the state approves?

I disagree with this proposal. For the most part, you’re getting the information you want in this thread. If you examine other threads in this forum, you’ll occasionally see the peanut gallery attack. I don’t think that’s right – dissent belongs in Great Debates, or perhaps the BBQ Pit. Not much we can do about it, though: either argue back or ignore them.

Anyway, back to your main topic. You might look at your ticket and see if there are any crucial mistakes. A few years ago, the NMA site had a post that described a ticket being dismissed because the cop had written “Volkswagen” for vehicle type, when the guy actually drove a Volvo. Look at vehicle color, license or registration number, see if your name is misspelled, etc. Usually they’re accurate, but invalid information can be grounds for dismissal, depending on the error.

You might consider adding the road where you got the ticket to the Speedtrap Registry at http://www.speedtrap.com/

What kind of car do you drive? And what color is it? Ok, this was at night, so that might not matter. But brightly-colored sports cars often attract a cop’s attention. One friend cringed when his son painted his high-performance '67 Dodge “arrest-me yellow”.

Do you have a radar detector? If not, you might check http://www.caranddriver.com/ and click on Radar Detectors for some comparisons. Their highest rating went to the Valentine One, so that’s what I bought. (Caution: it ain’t cheap.) They also include an interesting article on the case against Lidar, in case the cop used that against you.

You mentioned front plates. I used to get pulled over (but not ticketed) a lot while driving through Arkansas. That stopped happening when I took off my front license plate at the rest stop in Texarkana. Many states don’t require front plates, and when cops see one, they always seem to want to investigate. Also, front plates are a flat surface that reflects radar and lidar. That’s doubtless why cops want the state to keep them.

This is off-topic, but some Teeming Dozens from Houston are planning to meet for dinner this Sunday, and the following Saturday. See http://www.straightdope.com/ubb/Forum4/HTML/003735.html for details, if you’re interested.

You’re only as old as you look.

32

You miht be interested to know:

I don’t know what the cop was trying to say, but his answer is VERY intriguing. There is an even bigger question begging to be asked by those in science…but it never arises:

I won’t dig into the details, but I will say that the Doppler shift of lightwaves can be thrown off by a temperature gradient (i.e.: convection currents) which causes the air to act as a mirror. The gun may be calibrated, but did it actually record your true speed??? Especially from certain angles, I really have to wonder about the use of this technology.

I wonder if anyone has found science articles from reputable sources about the limits of this technology due to ambient conditions, etc. If so, I’d be curious to read more.

This might help the OP as well.

33

RADAR uses radio waves, not light waves. Its accuracy is not affected by temperature gradients or atmospheric conditions (though they may affect its range).

34

there is something morally wrong in outlawing a normal activity, such as driving 55 mph on a open straight, lightly traveled road.
There is a safe speed that one can travel at, as one goes above or below then more acidents happen. here in NY since the 65mph speed limit, the thruway has reported the lowest accident rate in years (they claim that it is because of sholder improvments, but we know the real reason). I have heard that every state expect Montanina which have rasied the limit has had a decrease in acidents.
its just a game that they play, they won’t tell you the enforcement tolerance, set the limit too low so everyone is in violation and pull who ever they want over.

35

Raza, FYI! Radio waves ARE light waves! Radio waves are part of the electromagnetic spectrum which we call “light” in brief.

Radio waves travel at the speed of light, otherwise, your radio would have some MAJOR delays! They do not travel at the speed of sound!

This is a common misperception.

36

Radio waves are the same as light waves? In what space/time continuum?

It’s a common “misperception” that radio waves travel at the speed of sound? Ya, maybe among second graders.

37

Raza, I hope you’re joking…

Radio and light are both forms of the same thing. Scientists usually call the entire electromagnetic spectrum “light” and then refer to the part that we can see with our eyes as visible light. It’s confusing because of the general way that the word “light” is used in the English language.

There is no difference between visible light waves and radio waves except for the frequency of the cycles of the waves. They’re both made up of streams of photons moving through space. The reason they behave differently is because of the difference in frequencies, and associated differences and effects caused thereby, but now I’m beginning to get beyond my level.

38

Raza, if you wish to contradict, at least please offer an explanation. A radiowave is a form of electromagnetic radiation, is it not? Please enlighten us all if you have some knowledge to share.

Thank you, “Johnnyharvard”, for confirming my position on radiowaves.

39

Jinx said “Radio waves ARE light waves”, not the other way around. I agree that light (using the common definition of those frequencies we can see) waves are radio waves; I don’t agree that radio waves are necessarily light waves. IOW, I don’t agree they are interchangeable terms.

My esteemed colleague johnnyharvard points out “There is no difference between visible light waves and radio waves except for the frequency of the cycles of the waves.” True, but it is a bit like saying that the only difference between steam and ice is temperature; while it is a true statement, we wouldn’t use those terms interchangeably.

As to jinx’s hypothesis that convection currents can alter the frequency of the doppler return, that is a new assertion for me. While there have been many tests that demonstrate factors that will reduce a speed reading, I have not read any claim of situations where the reading would be increased.

I think that’s why we’re all posting.

40

from Raza

from Jinx:

from johnnyharvard:

from Raza:

Semantics. We all agree that light refers to the visible spectrum. We all agree that both light and radio are electromagnetic waves. It’s the overlap that is confusing.

Usually, light is left to refer to the visible range, plus ultraviolet and infrared. Radio is a specific range of em different than light. Microwaves are a different range. Same with Gamma radiation, etc. I went looking for some links to help here, but wasn’t doing well.

Suffice it to say the original poster meant “electromagnetic radiation” and put “light”.

As for temperature gradients affecting radar, I do not know. They can affect light, but I don’t know if radio wavelengths are affected.