| Mekanik22 |
Is it possible for photoradar to get you while your driving and THEIR driving at the same time? If it is, is it legal for them to do it? By both moving, say your speeding and their driving behind you is it possible/legal?
No this never happened to me, so don't start throwing accusations around. I was just curious. |
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| MX5 Miata Guy |
| Not how PR works...but roving radar exists, in a number of innocuous EPS ghost cars. |
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| snugs |
quote:
Originally posted by MX5 Miata Guy
Not how PR works...but roving radar exists, in a number of innocuous EPS ghost cars.
...roving radar? Are you talking about the regular radar that's set up in the patrol cars or something different? |
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| dance_of_curse |
| scooby doo?:bthumbup: i think ive heard about it before....meh just watch out and dont speed |
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| TrevorK |
quote:
Originally posted by snugs
...roving radar? Are you talking about the regular radar that's set up in the patrol cars or something different?
It's setup in unmarked cars, or at least the ones I know of. |
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| snugs |
quote:
Originally posted by TrevorK
It's setup in unmarked cars, or at least the ones I know of.
But its the same old front or rear facing radar that is installed in the patrol cars. :dunno: |
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| MX5 Miata Guy |
Yes...as in radar! Instant on, when they're right behind you.
They're using the pre-banana versions of the Caprice...the old boxy ones. Quite a surprise to see. |
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| dance_of_curse |
| look out for a shit brown one in mill wood with a majorly obese cop in it |
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| snugs |
quote:
Originally posted by MX5 Miata Guy
Yes...as in radar! Instant on, when they're right behind you.
They're using the pre-banana versions of the Caprice...the old boxy ones. Quite a surprise to see.
File this one under whoop-de-do. Ghost car with standard radar, wake me up if the EPS gets some neat new hardware. :p |
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| No-Pistons |
| they best thing about that moving radar is they leave it on in the city. So your dectors will pick it up. |
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| Mekanik22 |
| I thought the ones in unmarked patrol cars were LASER radar, not photo? I dunno. I could have swore when I saw this on the news, they said it was laser where it doesn't take your picture. :dunno: |
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| inglewood |
quote:
Originally posted by Mekanik22
I thought the ones in unmarked patrol cars were LASER radar, not photo? I dunno. I could have swore when I saw this on the news, they said it was laser where it doesn't take your picture. :dunno:
somehow i don't think you can use laser in a moving vehicle.
edit: no such thing as laser radar...it's either lidar or radar...two separate devices for measuring your speed. |
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| SilverNeonRacer |
quote:
Originally posted by inglewood
somehow i don't think you can use laser in a moving vehicle.
edit: no such thing as laser radar...it's either lidar or radar...two separate devices for measuring your speed.
Umm correct me if I'm wrong.. but I've been nailed by laser and there's a check box on the bottom of the tickets saying laser. |
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| inglewood |
quote:
Originally posted by SilverNeonRacer
Umm correct me if I'm wrong.. but I've been nailed by laser and there's a check box on the bottom of the tickets saying laser.
yes, you're absolutely right. it does say laser. and it is a laser. however it's never referred to as laser radar, because those are two seperate gadgets for measuring your speed. but the proper term for it is lidar. why? cuz lidar stands for light detection and ranging. it works on the infrared spectrum, you can't see the beam, it's around the same wavelength of the waves from your microwave, but nowhere near as powerful (thankfully). but yes, it is a laser, but they never use it in a moving vehicle, cuz if you think about it, it has to be aimed precisely, unlike radar, which is a wide angle beam, and displays the most powerful signal response based on the doppler effect.
sorry, i'm an engineer and this is my area of study, i get a little excited about it sometimes. |
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| SilverNeonRacer |
I had a rough idea how they work....
maybe you can answer this one...
With standard radar in a moving vehicle... is the radar tied into the vehicle so it automatically subtracts the cruisers speed from that of what the radar gun shows or is it up to the cop to do that manually? |
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| No-Pistons |
| when me and my friend got pulled over in jasper. Tj (my friend) asked to see it. It showed 2 speeds the cops speed are speed. ahh thats a $600 ticket that i wish never happed but. He said i had a suped up mazda 6 lol. |
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| SilverNeonRacer |
a $600 ticket.. how long ago was that? back in 99 my wife got pulled over as well as an Iroc Z28 cause she pwnd him 3 times on Jasper, she only got a $220 ticket and 6 demerits. The ticket was for "racing for wager or bet on highway" they never bet anything, however the cops did say him and his partner where betting, he even asked how much pedal she had left, and she said lots, he seemed kinda shocked heh.
They got yanked right in front of BPs. |
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| inglewood |
| With the "moving" radar, the radar gun recieves two siginals, one which is bounced of stationary objects, which reflects back and gives the speed of the vehicle. The second signal which produces your returned speed, measures the speed of the fastest moving vehicle in the radar beam, or in some cases the largest vehicle. This is rare, but it happens. Because the radar measures the "speed" of a stationary object, it automatically subtracts the speed of the originating vehicle, and ultimately, you end up with the speed of the target vehicle. The radar does display the speed of the officer's vehicle too. Hope that answers your question. |
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| mwdguy |
quote:
Originally posted by No-Pistons
when me and my friend got pulled over in jasper. Tj (my friend) asked to see it. It showed 2 speeds the cops speed are speed. ahh thats a $600 ticket that i wish never happed but. He said i had a suped up mazda 6 lol.
highest ticket is 402 bucks if i do recall ... he must have gotten more than one |
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| SilverNeonRacer |
| K.. but what if you live out in the wheat fields like I do, and there's not anything around cept for the road, you and the cop. And how does the radar know what a stationary object is? IE not the car infront of the cop. |
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| inglewood |
quote:
Originally posted by SilverNeonRacer
K.. but what if you live out in the wheat fields like I do, and there's not anything around cept for the road, you and the cop. And how does the radar know what a stationary object is? IE not the car infront of the cop.
anything that can reflect a radar beam will produce a response on the radar system. unless the entire world is blanketed with the same material used to manufacture the F117A stealth fighter, chances are, there will be something that will reflect even a slight amount. A tree can produce a signal, a traffic sign (which also happens to produce a strong refelction because of the material used to manufacture them) and likely so can the road surface. Remember, the radar does not diffract out in a straight line, we're not talking about a concentrated laser beam (such as the infrared used in the stationary lidar systems). Radar goes up, down, left, right...just visualize a cone coming out of the front of the antenna. |
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| SilverNeonRacer |
ahh I figured teh road wouldn't work you'd figure the signal would just refract and change directions rather than "bounce back"
I'm only asking cause there have been a couple times where I've been doing 15 over and get a ticket for 25 over with both lidar and regular radar |
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| mwdguy |
quote:
Originally posted by SilverNeonRacer
ahh I figured teh road wouldn't work you'd figure the signal would just refract and change directions rather than "bounce back"
I'm only asking cause there have been a couple times where I've been doing 15 over and get a ticket for 25 over with both lidar and regular radar
get your speedo checked |
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| SilverNeonRacer |
welll.. 1 vehicle I knew the speedo was off by 5km/h @ 100km/h so if my speedo said 100, I was doing 105.
And the last car in question was an 02 Neon LE, remember when they had that radar thing setup on the cap during the construction that showed you your speed, well I went through that thing in the middle of the night with my speedo at exactly 50, and it showed 50 on the radar.
The wife's Neon R/T is off, I would be doing 100 in mine, she would be following and over frs told me I was speeding, I said I wasn't, she said I was doing 110... so on 2 brand new almost identical cars the speedo was off by 10km.. on the more expensive one. the only diff really betweent he cars was she has the magnum engine and a 3.94 gear ratio and mine had a 3.55 ratio. And well tire sizes too I had 185/65/15s she had 195/50/16 |
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| inglewood |
quote:
Originally posted by SilverNeonRacer
ahh I figured teh road wouldn't work you'd figure the signal would just refract and change directions rather than "bounce back"
I'm only asking cause there have been a couple times where I've been doing 15 over and get a ticket for 25 over with both lidar and regular radar
very much possible. remember, the road surface is not perfectly flat, so as much as it'd seem that you don't have anything to create a reflection, there is...
as for the error in speed measurement...as much as it's possible, it's very unlikely. especially with the new laser (lidar) guns that LTI has released. Generally, if the angle is too sharp for measuring the speed of a vehicle, it will produce an error. In the event that your vehicle is measured at an angle, the speed measured will always be lower than you actually are because of the cosine law. think of a right triangle from grade 9...your actual speed is the hypoteneuse, and the speed measured is a component of it based on the angle that beam (laser or radar) is hitting your vehicle. In the event of laser, the older model, the LTI Marksman 20/20 did have a "possible" issue in which if it panned slightly, it would give a higher reading because of it shifting it's frame of reference. This would be when the beam is aimed at a part of your car, and a slight bump actually shifts the beam to another part which creates an additional horizontal displacement in the beam. Now, this is very unlikely because it only takes about a 1/3rd of a second to measure the speed of a vehicle using these laser systems.
so in general, chances are it is your speedometer that is probably off. 10 km/h difference is pretty big...you should probably get that checked out. |
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