View Full Version : can cop shoot laser from moving car?
littledan
12-09-2003, 10:25 AM
alright here's the deal.... my freind was driving on highway 2 north near ponoka. he moved in to the left lane to pass some traffic and was going 120. a car came up very fast behind him... when it got close he noticed it was a cop.. the cop came right up to his back bumper so my friend sped up to move into the right lane as the cop seemed like he wanted to get by. right then he threw on his lights and pulled him over. cop gave my buddy a ticket for 135 in a 110 and wouldn't even let him explain.
here is my question:
Can the cop shoot laser from his car moving at highway speeds?
Seems like bullshit to me since the cop circled laser on the ticket and told my friend he shot him with laser...
ryder_23
12-09-2003, 10:27 AM
doesnt it say radar/laser on the ticket???
no cops cant shoot laser while moving, but they can shoot radar. He mighta clockd you way down the road and didnt realize it.
DUBBED
12-09-2003, 10:29 AM
isn't it illegal for them to use the gun while moving?
I thought that came up somewhere on this forum once.
rage2
12-09-2003, 10:29 AM
Good old Ponoka, speed trap capital of Alberta.
He's screwed haha. Pay the fine, get the demerits, there's no way you can fight those bastards there.
ryder_23
12-09-2003, 10:44 AM
Originally posted by DUBBED
isn't it illegal for them to use the gun while moving?
I thought that came up somewhere on this forum once.
laser wont work, it will just display err. code on it. Radar they can use while moving, rcmp do it all the time. I bet your friend was just clockd a few km's back and didnt realize it.
LAser has to be stationary, so your buddy could have been nailed a few clicks back, otherwise, radar can be used while moving from either direction.
Why would a lazer need to be stationary? Lazer and radar work on the same principle, only lazers are more accurate because there is less spreading, and therefore can be more targeted. As long as the cop car had cruise set and was travelling at a constant speed, both radar and lazer reading can be adjusted to compensate.
Alpine Autowerks
12-09-2003, 11:24 AM
laser has to be aimed and only measures the speed (doppler shift) of the relected laser beam.
rader broadcasts a cone (some in both directions) and can dicriminate vehicle speed from the average background reflection, speed of the largest reflection and better units can isolate the fastest return relection
Originally posted by lint
Why would a lazer need to be stationary? Lazer and radar work on the same principle, only lazers are more accurate because there is less spreading, and therefore can be more targeted. As long as the cop car had cruise set and was travelling at a constant speed, both radar and lazer reading can be adjusted to compensate.
Um...Laser and Radar work on nothing remotely close in principle bud. Laser on the otherhand (Light Amplification by Stimulated Emissions of Radiation for the techies on here)
Radar (RAdio Detection And Ranging) is such a far broader wavelegth that you can opperate it with the device in motion.
All stationary traffic radars measure on-coming traffic; some models also (and/or) measure going (receding) traffic. Virtually all moving mode radars can operate from a stationary position or a moving patrol car. Moving mode radars usually require a minimum patrl car speed for movng mode operation. All moving mode radars (in moving mode) measure on-coming (opposite lane) traffic; some can also (and/or) measure receding (opposite lane) traffic (requires aft antenna). Some moving mode radars can measure targets traveling in the same lane (direction) as the patrol car (front and/or rear antenna). Same-lane radars require a minimum speed difference (3 kph or MORE) between the target and the cop car. Moving radars also measure patrol car speed (ground speed), most also display patrol measured speed. Many radars track only one target at a time; some models have the option to track and display two targets -- the strongest (may be closest or largest) target (echo) and the fastest (or a faster) target in the beam.
Most traffic radars have a relatively wide beam (10 to 25 degrees) that easily covers several lanes of traffic at a relatively short range. Detection range (in the beam) varies with radar and target reflectivity and may be as low as 30 meters or less to 1.5 km or more. A radar may track a distant large target instead of a closer small target without any indication to the operator which target the radar is tracking
Laser radars (LADARS) transmit pulsed laser light to measure target range. The time it takes for a laser light pulse to travel (at the speed of light) from the ladar to the target and back is used to compute the distance from the ladar to target and back (distance pulse travels = speed of light x time). Target range from ladar is half of this distance (Range = 0.5 x speed of light x time). The change in target range over time (1/3 second typical) equals target velocity. Laser radar must transmt a minimum of 2 pulses to get at least 2 range measurements at 2 different times to compute speed. In reality laser radars transmit tens to hundreds of pulses per second so no matter what the Laser will own you.. Most Laser devices only have a spread of about 50cm over the distance of 175 meters, far more narrow than Radar and as such not wise for moving vehicles as you would have to be constantly aiming it.
Apertures for ladars are optical focusing devices (lenses, prisms, and/or mirrors) used to collimate laser energy into a narrow beam. Some models use the same aperture for transmit and receive; some use separate apertures (one for transmit and one for receive).
2 extremely different devices, so now you ahve been informed :)
Khyron
12-09-2003, 02:03 PM
Not only does it have to be stationary, but because the beam is so tight the gun has to be braced either on a tripod or a car window. Moving the hand a centimeter means the end of the beam moves like 5 meters when shooting 1km away (no, I didn't do the math).
But yes, the cop zaps you, catches up to you with the lights off, then when they are on you, flip them on. Otherwise people (like me) would run (and get away with it).
Khyron
for more enlightenment, read here (where ben's info is from also)
http://coprader.com/preview/chapt1/ch1d1.html
pretty interesting stuff
littledan
12-09-2003, 02:46 PM
shit! so i guess he can't get out of his ticket... thanks for the info guys.
Ponoka has a little power trip when it comes to thier couple of KM's on HW2. Your bud is basically screwed. They have an inferiority complex. angry at all the folk who zip by all important and not hickish.
Originally posted by Ben
Um...Laser and Radar work on nothing remotely close in principle bud. Laser on the otherhand (Light Amplification by Stimulated Emissions of Radiation for the techies on here)
Radar (RAdio Detection And Ranging) is such a far broader wavelegth that you can opperate it with the device in motion.
All stationary traffic radars measure on-coming traffic; some models also (and/or) measure going (receding) traffic. Virtually all moving mode radars can operate from a stationary position or a moving patrol car. Moving mode radars usually require a minimum patrl car speed for movng mode operation. All moving mode radars (in moving mode) measure on-coming (opposite lane) traffic; some can also (and/or) measure receding (opposite lane) traffic (requires aft antenna). Some moving mode radars can measure targets traveling in the same lane (direction) as the patrol car (front and/or rear antenna). Same-lane radars require a minimum speed difference (3 kph or MORE) between the target and the cop car. Moving radars also measure patrol car speed (ground speed), most also display patrol measured speed. Many radars track only one target at a time; some models have the option to track and display two targets -- the strongest (may be closest or largest) target (echo) and the fastest (or a faster) target in the beam.
Most traffic radars have a relatively wide beam (10 to 25 degrees) that easily covers several lanes of traffic at a relatively short range. Detection range (in the beam) varies with radar and target reflectivity and may be as low as 30 meters or less to 1.5 km or more. A radar may track a distant large target instead of a closer small target without any indication to the operator which target the radar is tracking
Laser radars (LADARS) transmit pulsed laser light to measure target range. The time it takes for a laser light pulse to travel (at the speed of light) from the ladar to the target and back is used to compute the distance from the ladar to target and back (distance pulse travels = speed of light x time). Target range from ladar is half of this distance (Range = 0.5 x speed of light x time). The change in target range over time (1/3 second typical) equals target velocity. Laser radar must transmt a minimum of 2 pulses to get at least 2 range measurements at 2 different times to compute speed. In reality laser radars transmit tens to hundreds of pulses per second so no matter what the Laser will own you. Most Laser devices only have a spread of about 50cm over the distance of 175 meters, far more narrow than Radar and as such not wise for moving vehicles as you would have to be constantly aiming it.
Apertures for ladars are optical focusing devices (lenses, prisms, and/or mirrors) used to collimate laser energy into a narrow beam. Some models use the same aperture for transmit and receive; some use separate apertures (one for transmit and one for receive).
2 extremely different devices, so now you ahve been informed :)
Different devices, similar principles. In both cases you are sending an EM wave that bounces off the object in question and back to the source. The calculations are different (doppler shift of RADAR to determine the speed of the object vs time difference it takes for the laser pulse to be reflected, giving change in distance over time of pulses to get the speed of the object)
It's not impossible to get a laser reading from a moving vehicle, just extremely difficult and impractical.
Originally posted by lint
It's not impossible to get a laser reading from a moving vehicle, just extremely difficult and impractical.
Thats basically what I was getting at in your original question, its just not practical. :)
Khyron
12-09-2003, 03:39 PM
Originally posted by lint
[B]
Different devices, similar principles. In both cases you are sending an EM wave that bounces off the object in question and back to the source.
Similar, as in light vs sound? Radio vs TV? Fibre Optics vs 2 tin cans and a piece of string? Everything has similar principles if you dig deep enough.
Khyron
ryder_23
12-09-2003, 04:14 PM
Originally posted by lint
It's not impossible to get a laser reading from a moving vehicle, just extremely difficult and impractical.
Like I told you, if a cop is driving, trying to shoot laser, looking threw the site, shooting with one had, driving with the other, it would be pretty dangerous, not to mention they'd need to make a laser that is capable of moving and detecting how fast the cruiser is going
redbaron303
12-09-2003, 04:35 PM
I'm not reading all this... but Dan, pm me... I have a friend in law enforcment that may be able to help.... if he was apparently clocked by a cop using laser in a moving car (or even one w/ the windows up) it's not possible for him to have an accurate reading. My friend had his ticket thrown out b/c of something like that.
ryder_23
12-09-2003, 04:37 PM
New generation laser(LIDAR) can be shot threw windows, they did this so cops can stay warm in the winter :D. and from the sounds of it, cop wasnt moving.
redbaron303
12-09-2003, 04:40 PM
Then he may be screwed (here in Etown we apparently don't have that type of laser yet).... So he'd have to have the window down or have it on a stand freezing his ass off in the cold.... but he didn't get tagged in Edmonton, sooooooo.....
IMO --->> It's worth it to fight any ticket b/c a little reduction by the prosecutor could be substantial enough fine or demerit wise...
Originally posted by Khyron
Similar, as in light vs sound? Radio vs TV? Fibre Optics vs 2 tin cans and a piece of string? Everything has similar principles if you dig deep enough.
Khyron
As I stated, they're similar in that they are both sending an EM wave that bounces off the object in question and back to the source. It's not light vs sound, it's higher frequency EM vs lower frequency EM. But if you want to call that digging, then so be it.
Originally posted by Ben
Thats basically what I was getting at in your original question, its just not practical. :)
Agreed, it's not practical. But that doesn't mean that it can't be done, which is why I was questioning these statements:
Originally posted by ryder_23
no cops cant shoot laser while moving, but they can shoot radar. He mighta clockd you way down the road and didnt realize it.
and
Originally posted by DUBBED
isn't it illegal for them to use the gun while moving?
and
Originally posted by Khyron
they'd need to make a laser that is capable of moving and detecting how fast the cruiser is going
If the laser can be programmed to calculate the speed of an object based on the time delays that it takes a pulse to hit the object and return to source, then they could also be programmed to compensate for the laser source to be moving at a constant speed.
Khyron
12-09-2003, 05:27 PM
And who's going to aim it? The beam is a few feet wide, and you have to hit something flat and reflective like a front plate. Cops like laser because it's pretty much undisputable (unlike radar which will often report the speed of a larger, more distant vehicle). Add more variables like vehicle speed, possible missed aiming - there's no point. Easier to just set a tripod up and reeeeeel them in.
Radar and Laser (and sonar for that matter) work on the same wave principle but they are nothing alike in practicality.
And quote properly.
Khyron
three.eighteen.
12-14-2003, 03:21 AM
stupid ponoka...:whipped:
hampstor
12-15-2003, 02:20 AM
ahh ponoka.. my friend used to own the movie theatre there, used to make the trip there to visit him.
the cops there were assholes. I was kept in the back of a cop car there for several hours because someone had called and said I was doing donuts. She kept me in the car and in the end she said: "well since we cant show that you did it i cant give you a ticket now. however i will go talk to my witness and if i FEEL like you deserve a ticket ill mail you one".
:thumbsdow
Cooked Rice
06-06-2011, 02:35 PM
Sorry for bringing this back up, but does this technology still hold true? I got shot from behind on my motorcycle on deerfoot from a moving unmarked CPS duranago and the officer marked laser on the ticket. :dunno:
nickyh
06-06-2011, 02:40 PM
Apparently they can, a former co-workers wife is with CPS and she confirmed it.
My husband was hit from a Sheriff on motorbike a year ago, and I asked the same question.
We fought it, requested "disclosure" so we would have the calibration records etc.... Ticket was dismissed since the sheriff moved to another jurisdiction.
Xtrema
06-06-2011, 02:55 PM
They can "eye ball" it if they want to.
gretz
06-06-2011, 02:57 PM
Originally posted by Cooked Rice
Sorry for bringing this back up, but does this technology still hold true? I got shot from behind on my motorcycle on deerfoot from a moving unmarked CPS duranago and the officer marked laser on the ticket. :dunno:
you are still screwed (still fight it though)... The cop can say he/she was at rest and lasered you, another unit lasered you, or it was an oversight and they can re-write the ticket...
In theory, the cop could have said you were doing 49 over, check just about any box on the ticket, and you'd still be in the same boat lol...
luxor
06-06-2011, 04:35 PM
Holy 8 year old bump. The violation ticket has a check box for Radar/Laser so either or could have been used to measure your speed. How was it marked laser only?
Cooked Rice
06-06-2011, 05:27 PM
They checked the box and underlined laser
luxor
06-06-2011, 07:12 PM
Originally posted by Cooked Rice
They checked the box and underlined laser
Well luckily for CPS and obviously not so lucky for you, the black box that says "The following does not form part of the charge" on your ticket appears before the Radar/Laser check box; this leaves you zero chance to get the ticket dropped.
How fast were you going?
Cooked Rice
06-06-2011, 11:18 PM
Not trying to get the ticket dropped, pretty sure everyone and their dog in this city knows it's next to impossible to have a speeding charge dropped. I was simply asking about the current technologies used. Because as stated earlier in this thread, laser was only effective when used stationary with a steady support.
luxor
06-07-2011, 11:31 AM
Originally posted by Cooked Rice
Not trying to get the ticket dropped, pretty sure everyone and their dog in this city knows it's next to impossible to have a speeding charge dropped. I was simply asking about the current technologies used. Because as stated earlier in this thread, laser was only effective when used stationary with a steady support.
Bullshit to the max. If they did laser you while moving and got a speed reading, but an incorrect reading, you wouldn't fight it? If they didn't get a a correct reading, would the ticket still be fair?
That's what I thought so don't bullshit. How fast were you going?
J-hop
06-07-2011, 11:49 AM
Originally posted by luxor
That's what I thought so don't bullshit. How fast were you going?
no doubt, this is the way i see this panning out, "so I was doing 120 in an 80 zone, cop was going the other way, cop hit me with the radar/laser and gave me a ticket for 120 in an 80 zone, can they actually do that shit?"
hmmm let me think :rofl:
I don't see what the problem would be with doing laser from a moving vehicle. GPS will tell the laser unit how fast it is moving (most good gps units are good down to the cm in the horizontal direction, not so great in the vertical in canada due to us using US satellites which orbit south of us making vertical calculations less accurate). so it seems to me it would be a simple matter of removing the laser units velocity from the equation?
Cooked Rice
06-07-2011, 02:10 PM
Originally posted by luxor
Bullshit to the max. If they did laser you while moving and got a speed reading, but an incorrect reading, you wouldn't fight it? If they didn't get a a correct reading, would the ticket still be fair?
That's what I thought so don't bullshit. How fast were you going?
If he never actually got a reading, why would I have been pulled over? I know I was going fast, I'm not saying the ticket is wrong. I initially just thought I rode past the cop without noticing and he shot me with the onboard radar. But I noticed the other day he underlined laser on the ticket which made me curious because I didn't know laser could be used in motion before, but I guess it does, unless he got me stationary and I just didn't see him. That's what i'm asking. Sure maybe the reading was inaccurate, but I know for a fact I was still doing the speeds he got me at. Sorry but i'm not another young chap trying to get out of a ticket, fact is this is the only time i've ever been pulled over for speeding other than the couple times I've been flashed by vans, and I've already paid it so you tell me how I'm gonna fight a ticket I pleaded guilty to already. The officer was polite with me, and straight forward, said I was being safe by doing good shoulder checks when lane changing, but it was busy and I need to slow it down a bit, he said "I had you between 126 and 124, I locked on at 124, that's what i'll write" asked me how the rest of my day was, wrote me my ticket, and sent me along.
Jesus
06-21-2011, 08:12 PM
The Sheriff's actually have rear facing radar in their highway patrol vehicles. So if you're speeding up behind them, they can ticket you that way as well. Kind of interesting I think.
soloracer
06-22-2011, 06:58 PM
Ponoka, eh? I hate to say it but you are pooched. I tried transferring a ticket from Ponoka to Calgary once because I knew I had a higher chance of pleading it here due to the backlog of cases. However, the crown in Ponoka knows this plus they have a judge there who likes to suspend licences so you are going to get nowhere trying to deal with the crown. Pay your fine and chalk it up to experience.
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