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Legal: Is the front surface of our cars difficult to "radar" without license plate?

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Old 07-01-2006, 11:55 PM
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Indycam
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How about you do a test for us ?
Find a radar gun , do runs at it with and without and find the distance for a clocking with and without .
I know you only got the two kids , a wife , a job , a house etc . You can find the time to do it , Ya ?
Old 07-02-2006, 12:10 AM
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ttAmerica RoadsterAWD
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Indy, you're funny! Correction: I have 3 kids and a miniature schnauzer to boot.

Actually, This is becoming an interesting thread full of ideas...Here's one: In Cali, my CHP friend can probably help us out on this. I'll hook up with him, go on a desserted street (yeah, right! in Calif. no such place), and do some runs with and without license plate. Stationary police radar, and hand held gun radar. I know he will do it for me (he owes me lots of favors).

Then......I'll disclose the whole enchilada at Garretts get-together. I'll even have him come with us and give us he's point of view from a CHP officers training.

Ok, who's going to go to Garretts BBQ??

Jaime

ps. I'm serious...I'll call him in the AM.
Old 07-02-2006, 12:16 AM
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Indycam
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Have you posted photos of 3 ? I only remember 2 helpers .
Old 07-02-2006, 12:37 AM
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ttAmerica RoadsterAWD
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Hi Indy...the third one under the engine bay is my son:

Last edited by ttAmerica RoadsterAWD; 12-11-2012 at 07:39 PM.
Old 07-02-2006, 01:52 PM
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Indycam
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A great photo .
Old 07-02-2006, 02:28 PM
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dfinnegan
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I love the pipe insulation on the jack handle. Now that's a great idea!
Old 07-02-2006, 02:37 PM
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LASER has a problem in the USA



Laser Speed Detection - EXPOSED!

From a USA Law Paper

Laser speed detection serves the same purpose as Radar; however, the two systems are totally different beyond their common goal. Laser uses a light beam and takes the measurements based on the speed of light. On the other hand, radar uses a radio beam and measures at the speed of sound, which is substantially less than the speed of light. While radar has a wave length of anywhere from inches to hundreds of feet, laser has a wave length of only 30 millionths of an inch. A typical radar beam is 18 degrees (X-Band) to 15 degrees (K-Band) wide.

Comparatively, laser has a beam that is one sixth of a degree. The results are drastic as the beam radiates out from the laser gun. While radar can expand to over 500-feet wide at a distance of one mile, the laser beam will only expand to 19 feet wide. At a more realistic distance of 1000 feet, the radar expands to over 100' wide while the laser system only expands to 3-feet wide.

Although laser sounds like the insurmountable speed detection system, it is not infallible. In fact, Lidar is significantly affected by weather conditions. Fog and clouds will severely reduce the effective measuring distance of the laser beam. For example, the laser system can only be used from a stationary set up rather than moving like some radar systems. Furthermore, laser can not be used through a windshield in most cases and the operator must have additional training that is typically not required for radar systems. Laser also has a problem getting an accurate reading when used at a severe angle to the target vehicle such as from an overpass or the far shoulder of the road. In addition, maintenance and calibration can only be performed by a factory authorised repair facility. As you can see, laser may be tougher to beat than radar, but it can be accomplished.

The primary target for the laser beam is the vehicle's licence plate. The light beam relies on a reflective surface for the successful return signal. This is why dark low slung vehicles with minimal or no chrome are so hard for laser to detect. The front licence plate should be removed and the rear plate should be painted with a high gloss clear coat to help defeat the laser beam.

Prior to each use, the laser gun should be locally calibrated by using all three of the following methods:

The self test button should be used and the reading should be 8.8.8.8.

A measurement of a non-moving target should result in a reading of 0 MPH.

The sight and audio tone should be tested by panning across a telephone pole. As the sight aligns with the pole, the audio tone should change indicating a positive contact between the beam and the pole itself.


Essentially, the LTI 20.20 Marksman is the main laser gun being used in the UK. The manufacturer claims a beam width of two feet at a distance of 1300 feet. The speed measurement time is one third of a second and the unit is equipped with an audio seek aid for positive target confirmation. The accuracy is alleged to be precise within 1 mph up to 60 mph and within 3% for speeds over 60 mph. Despite this impressive list of performance criteria, the Marksman has some notable downfalls.

For example, tests indicate that the Marksman lacks uniformity and has an unusual distribution of the beam intensity therefore resulting in a deviation from the aiming point. The especially high level of intensity along the right edge creates a deviation in the horizontal direction. What all this technology translates to, is the Marksman can actually detect a vehicle as close as five feet away from the actual target vehicle.

On June 13, 1996, New Jersey Superior Court Judge Reginald Stanton stated that he was not convinced of the accuracy of the LTI 20.20 Marksman. As such, he ruled that any readings taken with the LTI 20.20 would not be accepted as evidence in any pending or future speeding ticket cases.

For a defence strategy you need to be aware of laser's status in the jurisdiction where your citation was issued. Only a few US states have given laser "judicial notice" which is a legal ruling that establishes specific evidence as beyond dispute. Radar has "judicial notice" in every state.

If no judicial notice has been awarded, then the prosecutor will need to have an expert witness testify to the accuracy and reliability of the laser unit. If this expert witness ends up as a manufacturer's representative, you can make a motion to disqualify the witness since he (and his company) clearly has a financial interest in the outcome of the case and therefore, the witness is not impartial.

If judicial notice has been awarded, you certainly want to utilise the New Jersey ruling in your case preparation. The remaining preparation is very similar to a radar case. You need to focus the court's attention on the officer's training, the unit calibration and self-test methods, weather conditions during the time of the citation and the proximity of surrounding traffic. As with any case, your best strategy is hoping for the officer not to appear in court followed by careful preparation in case he does appear.



As yet I have not heard of a case in the UK using the LTI 20-20 faults, but if you know of a similar case let me know.


--------------------------------------------------------------------------------

Did he get you with LASER?
Questions to ask:


Are you trained to use this Laser gun?
How accurate is the Laser gun, and in what situations? How about when used incorrectly? Due to the Laser beam's narrow path of travel, the Laser gun can be very accurate when it is used correctly. However, if it were used incorrectly, the results can be useless and very misforgiving to you as the driver of the vehicle.
How exactly did you obtain my speed?
When was the Laser gun last calibrated?
Has the gun been subject to any knocks, Laser gun components are delicate and thereby sensitive. The actual gun would have to be stored and handled carefully as to not damage the innards.
How was the gun held, Laser guns cannot be mounted in a moving vehicle, because just a minor jolt will cause the reading to be inaccurate. Therefore, Lasers must be mounted and used from a stationary vehicle or on a tripod. Holding by hand is not as good
Make a note of the weather and the officers position. (See my section on "Things they don't tell you about Laser Guns")
Old 07-02-2006, 02:43 PM
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tafkai
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A recent court case in the USA has thrown a doubt on the accuracy of the LTI 20-20. At a recess in the proceedings the defendant's lawyer picked up the LTI 20-20 from the courtroom bench and proceeded to aim it at the back wall of the courtroom. To his complete astonishment, the gun registered a speed of 5.4mph. Bear in mind that he was aiming at a wall inside a building. He also noted how difficult it was to maintain his target accuracy by simply hand holding the device, with the registered speed fluctuating between -2.2mph and +5.4mph. A net error of nearly 8mph on a stationary object 20m away!
Old 07-02-2006, 02:54 PM
  #24  
tafkai
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To find out what is most important on your car, stand with the light source behind you (park in the sun at dawn or dusk), and look at the region of the car right next to the shadow of your ear. You are looking at light reflected back towards the source. Alternately, you can at night use a flashlight held against your ear and pointed at the car. Stand back by at least 30 feet to see light returned at an angle close to straight back at the source. Another technique is to park your car on a dark street, stand >30 feet away and take a flash photo. Most car parts have similar properties in the visible and near IR. Some special materials absorb in the near IR. and transmit in the visible and hence this test using visible light is not indicative that a special police-lidar countermeasure is working.
The licence plate is the strongest target on the front of the car. Licence plates have retroreflective material that returns light in a 4 milliradian cone angle (Colorado plate measurement)

Different States have a very large difference in the lidar return from the plates. Colorado is one of the lowest, using retroreflective paint on only the letters and a thin border. Most large states have better retroreflective material covering a larger area of the plate.

The strongest reflection of the rear of the car is an array of little corner cubes in the red tail light cover. All cars have a hexagonal array in the plastic tail light covers. These are just like a bicycle reflector. You can distinguish these retroreflectors from the tail light lens by the array pattern. The tail light lenses are in a rectangular array, and this corner cube array is in a hexagonal pattern. The second strongest target on the rear is the rear licence plate.

There is also a corner cube array on the side-front turn signal indicators. These do not present much of a target unless the police target you from the side in which case the cosine factor in speed measurement will give them too low a speed to worry about.

Next in strength are head lights, brake lights, turn signal indicators, and fog lights. Of these, headlights are highest, followed by turn signals and fog lights. The retroreflection mechanism is interesting. Light enters one-half of the light and is returned from the other half. I suspect that the light enters one half, hits the back reflector, is focused near the filament, expands to the other side back reflector, and is recollimated returning towards the original source. This phenomena happens over a moderately narrow range of angles directly in front of the car.

Grills, forward facing chrome, and any rounded specular material are the next strongest targets. Look for a bright glint from any rounded surface which always presents one small region facing the source. Flat regions are almost always pointed away from the source and hence do not contribute to the return.

B. Stealth Techniques. (What to do about these Lidar targets)
The licence plate is the most important on the front of the car, unless you are blessed with a plate without retroreflectors In some states you can legally remove the front plate. In some states it may be sufficient to paint over the retroreflective paint with glossy house paint to match the colour. Check your local laws first. Many states use 3M retroreflective material, which would be difficult to paint over inconspicuously. For these states it is preferable to use a lidar cross section reducing licence plate cover
The array of corner cubes in the tail light cover. These are on all cars, and are probably required by law. If you paint them black, a car driving by would not see your car on the side of the road as easily. The only thing I can figure is to get one of the licence plate covers that block IR., and cut out a piece and glue it over the corner-cube array. (Expect new products for this application to come out soon)

Head lamps, turn signal lamps, and fog lights. Get retractable headlights or glue a section of IR. absorbing licence plate cover over your headlights. Remove the fog lights, glue licence plate cover over your turn signal indicators. The "smoke" headlight covers that are on the market do a fine job of reducing retroreflection from headlights. The down side to these things is that they really aren't legal in most states.

The most extreme stealth includes taking care of all other possible glints. Get a flat black car bra, paint over flat surfaces with glossy paint, paint over rounded surfaces with flat paint. These returns are small compared to the Plates, cornercube array, and lamps.

Lidar (and radar) range goes as the fourth root of return signal power. By eliminating the single strongest return, the best you can hope for is to reduce the range by about a factor of 2 to 4, from reducing your cross section by a factor of 16 to 256. This is because even if you reduce the strongest return by a larger factor than 256, you probably have something else which returns the lidar signal by at least 1/256 as much as this strongest factor. When you eliminate the strong return you still have the other source of returns. To get a range reduction of more than a factor of 4, you probably have to apply stealth measures to multiple reflectors on your car. If you get the licence plate, the corner-cube array (back of car only) and the lamps I think you'll get your visibility under the average range at which police target cars
Old 07-02-2006, 02:58 PM
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For anyone who gets a laser ticket, we encourage you to fight it. That in itself isn't news, (we encourage everyone to fight all speeding tickets) but lasers are not on judicial notice in New Jersey. In fact, they're not on notice in 95% or more of the country's courts. The prosecution teams around the country are glad you don't know that.

What's "judicial notice" mean? When something has been given judicial notice, it means that the theory of operation has been proven to the court and expert testimony to prove that is no longer needed. Radar is one such example. Aircraft speed traps are another.

Laser, however, has not been proven to the courts, so the prosecution will have to fly in expert testimony to prop up their case and new toy) to prove that their latest gadgetry actually works as advertised.

Laser -cannot- be used while the cop car is rolling. The vibrations would scatter the beam everywhere. I've only been ambushed by a laser trap once, and the set-up had one officer doing the laser, another next to him radioing the to the chase vehicles, and 4 or 5 chasers. So, this is hardly a valuable use of scarce police resources!

In cases of aircraft tickets, if someone contests one, both the arresting officer and airplane spotter (or pilot, if the same) have to be hauled into court to say that yes, that driver was the one we stopped. Theoretically the same should happen with laser traps, but don't count on it until someone says something. ("Shhh. It's our secret. Don't let the public know" kind of stuff)
Old 07-02-2006, 06:32 PM
  #26  
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maybe you need one of these for the back window

http://cgi.ebay.com.au/YOU-HAVE-BEEN...QQcmdZViewItem
Old 07-03-2006, 04:45 PM
  #27  
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What part of CA? I'd LOVE to do this test - and my car should be ready in a matter of days. I've always wanted to know how accurate / reliable those guns "really" are in use. Of course, they're probably a heck of a lot more accurate when the target is in zero traffic vs. a pack of other cars. Maybe we get 2 or 3 guys to participate. I know a lot of p-car guys in the SF bay area who would do this.

Originally Posted by ttAmerica RoadsterAWD
Indy, you're funny! Correction: I have 3 kids and a miniature schnauzer to boot.

Actually, This is becoming an interesting thread full of ideas...Here's one: In Cali, my CHP friend can probably help us out on this. I'll hook up with him, go on a desserted street (yeah, right! in Calif. no such place), and do some runs with and without license plate. Stationary police radar, and hand held gun radar. I know he will do it for me (he owes me lots of favors).

Then......I'll disclose the whole enchilada at Garretts get-together. I'll even have him come with us and give us he's point of view from a CHP officers training.

Ok, who's going to go to Garretts BBQ??

Jaime

ps. I'm serious...I'll call him in the AM.
Old 07-04-2006, 03:37 AM
  #28  
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Hi Chance. It will be in the Pomona/West Covina/Chino Hills area (my old stomping grounds). If you can make it, them you can also drive just a little more south to our get together at Garretts home in San Diego!

Tafkai: it was not a lazer. It was a rear mounted stationary radar. Cop was in front of me parked on the right curbside.

Jaime
Old 07-04-2006, 11:56 PM
  #29  
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Talked to my CHP (Calif Highway Patrol) friend today. We're on! We will go to a relatively low traffic area, we will be on our cell phones, then we will test with and without license plate. We'll try a rear approach on the cruiser, then a front approach.

Anybody else with any suggestions for this experiment??

Jaime
Old 07-05-2006, 12:03 AM
  #30  
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Yeah, I'd like to see a multi-car test with one overtaking at a good clip on a couple of cars going at slightly different speeds. All while passing the radar zone. It seems like it'll be difficult to setup, but it would be nice to see how well they can pick a fast car from a moving set at different speeds.

Sounds like fun, actually!

Cheers,
Dave


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