If I was a cop sitting and watching traffic with the gun displaying a speed over the posted speed limit, obviously the vehicle moving faster than the rest of the vehicles would be the one most likely speeding. Other than that, I have no clue...I'm just glad I too have a V1.

 

http://auto.howstuffworks.com/framed.htm?parent=question396.htm&url=http://copradar.com/

 

the radars don't shoot a really "wide" beam, it is somewhat concentrated.

there's two approaches here.. most of the radar guns actually use laser (infra red) so that doesn't disperse/spread.

the ones that do use radiowaves are really fast at calculating speeds. they can calculate the speed a number of times a second, so it can spot a faster car/objects amongst others.. and then again if you're a cop and your radar just went off, its easy to just spot the fastest car amongst a group.

here in dubai/ad, we have a few roads that have more than 4 lanes.. apparently, the way radars are setup, they can't cover the entire 6 lanes, so some places have two radars fixed within a few distance.

the dubai radars take picture from front and there is no license plate infront of the bike :boobies

 

As said, with radar, the car that is obviously moving faster than the others is the one the unit will display. With laser, since the beam is very narrow, I'm pretty sure they have to look through the scope to pinpoint a specific vehicle. Not using the scope would make for an easy win in court.

 

With laser, since the beam is very narrow, I'm pretty sure they have to look through the scope to pinpoint a specific vehicle. Not using the scope would make for an easy win in court.

yep
with laser, you will usually see the cop either standing next to the car, or aiming it out a window....lasers are not fixed to the car like radar units are

 

They also need to be calibrated every day before use and logged in a log book. If you need to go to court with it, ask them to produced the log bok showing it was calibrated that day. If not, my dad (cop in Denver who is qualified to use radar and laser) says it's inadmissable.

 

Depends on the state. Here in NC you check it once you check on for work and after every inforcement action but you dont have to log it .

 

Radar

I believe also that radar tends to pick up the bigger object:flex:. So if a car is trailing behind you fast and your within speed limit the cop may think you are the speeder.

 

it goes beep b------beep----------------------beepppppp----beep-beeeeep-beeeeeeeeeeeeeeeeeeeeeeeeeeppppppppppppppp
your fukt...

thats about it bro

 

I think some people misunderstood my question. I wasn't asking how laser/radar guns work, I was wondering how they know which target their fixed radar device is picking up since there's no view finder. Some of you are saying that it picks up the fastest target, but how can that be admissible in court? Don't they have to prove that it was you that was detected on radar? How can they prove that if they didn't actually see you through a view finder?

 

yes, what your talking about is a radar gun and it picks up the speed of the vehicles in front and rear of the cop car - even while moving. He can also get your speed while driving the opposite way on the interstate (happened to me). There would be a couple of ways for the gun to determine how fast you are going, however I don't know the specifics of how radar guns work. I do know that rain and snow really hurts their range and the max range on one is about 1/4 mile (from talking to a police officer). Hope that helps. And oh by the way your bike is probably a lot harder to pick up on that gun than a car.

 

What if there are 3 cars driving along side of each other down a 3 lane highway. Which car will the hard mounted gun pick up?

 

don't know, maybe the closest? Maybe the fastest?

 

I dont know how they know and I wondered the same thing when I got popped a couple months ago... On my way up to San Francisco a chp was hiding behind a bush in the median... It was a long stretch with no exits for miles upon miles with long sweeping turns so I was riding a good pace...

He comes up to me and says:
I got you going 88 coming toward me and 107 before I lost you around the turn... My thought is instantly, great triple digits, Im 400 miles from home and screwed... than as soon as I thought that... he says, "I just bought an R1 myself and was wondering what kind of exhaust you got on there. It sounded wicked accelerating away.":sneaky
we continued to bs about bikes for 10 mins on the side of the road when he tells me "the next unit is in the next small town about 40 miles away so your good until then, ride safe" he gets in his squad car and takes off after a car speeding by... I pass him and the person he pulled over a minute later and we exchange a friendly wave:hellobye by far the the best experience i've had with a chippy

 

alright, radar guns send out a cone shaped wave so the farther out the beam goes the wider the spead of what it will pick up. Also most basic radar units pick up the largest vehicle in its path regardless of direction of travel, but many advance units do have an option for picking up the fastest vehicle along with only picking up certain directions of travel.

As far as you main question is concerned, It's is the Officers determination of which vehicle is traveling the fastest. If you are using the radar as trained. you would.
1. observe traffic visually for speeders, then visually estimate speed and range of possible suspect vehicle.
2. then use the radar to back up observations.

A big part of radar training is the visual estimation of speed and distance during both day and night. At least here in KY it is, and you have to be within 5 mph and 50 yards in order to pass that portion of the training. The instructors do about 20 passes during day and night for that test.

hope it clears up some info for you

 

good info. Can police officers run radar when driving behind you??? Or how about if they are coming head on?

 

yep

 

@won: that's the coolest damn cop ever I only wish I'd have a cop pull me over for that reason!


@lawman: i always thought there was a more specific way of picking up the specific car. it seems strange to me that the radar gun picks up the fastest vehicle. Is it the fastest vehicle over a distance? or just the fastest vehicle in the path of the radar beam? just seems so inexact.

 

@won: that's the coolest damn cop ever I only wish I'd have a cop pull me over for that reason!


@lawman: i always thought there was a more specific way of picking up the specific car. it seems strange to me that the radar gun picks up the fastest vehicle. Is it the fastest vehicle over a distance? or just the fastest vehicle in the path of the radar beam? just seems so inexact.

I was told by a police officer after being pulled over on base when I wasn't even the one speeding that it picks up the biggest or the fastest vehicle. There seems to be a problem with that when it's the biggest and the fastest vehicle that he picks up, but still pulls me over. I don't get how there is a car behind me at a light, and the car ends up 20 feet in front of me in the next lane within 2 blocks, and the cop determines I was the one that was speeding. :dundun: Cops on base seem to be the most idiotic cops I've ever come across. They seem to have something to prove to people in the military. Cops off base tend to be a little more generous when they find out I'm in the military. I was coming through the gate on my bike with a bright-ass yellow rain jacket on that had reflective strips on the sleeves. No vest is required anymore on my last base, as long as you have reflective material (stripes on the sleeves) during low light conditions, and bright colored long sleeve top in daylight hours. It had been at least a half hour since the sun started coming up, and was pretty bright out. I had a black backpack on. This idiot cop at the gate tells me I have to wear my jacket over my backpack because my backpack doesn't have reflective material. I tell him my reflective material is on my sleeves, and no jacket is designed to be worn over a backpack and that I'm not even required to have reflective material at this time of day. THis guy tries to argue with me about the rules of riding a motorcycle on the base after not even 2 weeks prior, the Master Chief that WROTE the rules gave us a lecture about them at our safety standdown. He then tries to say the base commander instructed them to enforce wearing reflective material on the backpack. I asked him to produce the documentation stating that. No rule on base is a rule unless it is in writing. He said he didn't have it. I asked him where I could find it. He told me it's probably at base legal. I asked him to call them and get a copy. Then he had the nerve to ask ME why I'M giving HIM a hard time. He said he won't let me through the gate either way. So I told him I'll just go to the other gate and they'll let me right in. I knew 100% for a fact I was exaggerating the requirements for riding on base. When they say bright colored, they mean any color that's not black or dark. I was wearing screaming neon yellow WITH reflective stripes! He finally let me go through because I'm sure he could tell I knew what I was talking about and he was about to look real stupid if he tried to push it any further. But just so I didn't get anymore assholes like him stopping me, I exaggerated the rules again and had the parachute riggers at work sew glint tape all over my bag.

I guess this kind of went off topic but I started getting into a little rant.

 

ok, here's how it works in oregon....

1. identify suspect vehicle (the one going faster than the others)
2. estimate it's speed (with a little bit of practice you actually get really good at it)
3. get a reading on the radar unit (should be in the ballpark of your estimation)
4. get a steady tone from the radar unit
5. verify your patrol car speed with what is displayed on the radar unit to make sure the numbers are right
6. stop suspect vehicle


also, just for info. you don't actually calibrate it everyday. you conduct external checks to ensure that the device is operating correctly. the calibration is done by the company every so often. at the beginning of shift you do your external checks with tuning forks. then after you write someone a ticket, you do it again to ensure that it is still operating correctly. hope that helps.