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How sophisticated is radar or laser speed detection on a divided four lane highway?
Two cars come over the hill essentially right next to each other...your equipment tells you at least one of them is speeding. Can you easily tell which one?
You pull over the black guy.
tRCMB - Visit at your own risk of being disgusted.
I'm not a cop, but have used a laser radar. You can easily point the laser at one car to get the speed, and then reset it and point it at the other to get the 2nd car's speed as well. Both would be dead nuts accurate.
Yeah but he's asking how accurate would the police officer be at aiming a radar at two distinct objects traveling at ~70 mph in about 3-4 seconds.
That's easy too. You look down the center (imagine a scope on a gun) and there's a little red dot you have to center on the front/grill of the car. 3-4 seconds might make it tough, as well as coming over a hill, but if on somewhat flat surface you can start aiming the laser a ways out and have plenty of time to gauge the speed of two vehicles.
There's actually a lot of truth to what you're saying.
RCMB Premium Poster
No shit, that is why it is funny.
funny to who?
It's pretty sophisticated and pretty accurate. Not a cop but very knowledgeable of the physics at play.
This post was edited by TheBlitzIsOn 20 months ago
Smells like bacon in here
Thank you for sharing
Either one is equally accurate. If you use radar, it will choose the fastest vehicle, you then watch to see which vehicle is overtaking the other. A clear tone means a solid lock. After watching vehicles for so long, it gets pretty easy to accurately estimate within a few mph as they approach you.
I prefer my LIDAR. There's a small red dot that you aim at a reflective surface on the vehicle (headlight or front license plate work the best). In two seconds I can clock both vehicle, then focus on the one with the fastest speed. Again, a solid tone means a good lock on the vehicle.
As a little aside, for those of you with radar detectors, our radars now-a-days are only on for a few seconds when we see the vehicle, you then push a button to put it into sleep mode. The LIDAR detectors don't work and if you're using a jammer it's pretty obvious from the cop's perspective.
Everyone who is laughing so they don't cry.
Yeah and when you turn that radar on for a few seconds on a car in front or behind me, my Valentine 1 (one of THE best long range radar detectors on the highway) warns me you are out there and I slow down before you ever get to me.
Your few seconds of use doesn't make you invisible.
LIDAR on the other hand, is much harder to detect/defeat so I bow to your superior means of clocking a vehicle.
So let me refine my example.
Suppose I'm passing on the right...you hit us with instant on radar.
My detector goes off and I pull my foot off the gas.
There is some chance that the person in the other car would be wrongly identified as the fastest car?
by the time you react and slow your car ive already locked in your speed. the radar is used as a tool to justify the violation of speeding. sometimes you will get an erroneous reading. but the technology in the radar units now will tell us which vehicle is traveling the fastest and you can also easily detect which one is pulling away.
radar detectors do two things. #1 they will you when you are fucked. #2 has the possibility of pissing the cop off to where you wont let you go.
every cop is different. i dont pull anyone over on speeding unless they are 10 over or more. i know highway patrol guys who pull people over going 6 over. it is what is it
Ten over is what I set the cruise for on the highway.
I was really hoping you'd tell me that it's difficult to tell which car is moving the fastest in the split second as the cars come into view....oh well!
I can undestant the accuracy if the officer is stationary and actively engaged in selecting a target...Does the same logic apply when the police car is moving and the officer is partially distracted with driving?
If we promise to upvote you for life will you increase that to 20 above?
Stupidity knows no bounds.
Instant on is tough to beat but I find 99% of the time the radar is left on and it's detected in plenty of time to slow down. Maybe the cop is sleeping and just trying to slow traffic like those portable radar speed signs the municipalities use. I've used a Valentine for at least 15 years and I'm pretty sure it's saved me a lot of money. It's not like I'm breaking speed limits 24/7 but I like to know when I'm being watched.
In the situation the OP is asking the radar doesn't tell the officer which car is speeding, the officer must make that determination. All the radar does is report the fastest speed.
LIDAR is manually "shot" directly at the car so the officer already knows which car is being targeted.
Monty Burns I must respectfully disagree with you regarding the reliability of radar detectors. I am very sure many cars you ticket for speeding have a radar detector onboard. Of course you see radar detectors as worthless. However for every car with a radar detector you pull over there are many, many other cars on the road with radar detectors you didn't catch. They work to detect the presence of microwave radar. Some do that better than others.
LIDAR detection is tough to get right (near impossible) because it is manually aimed and fired. By then your caught. Just pull over and wait for the officer.
I don't care if the presence of a radar detector pisses off the officer either. If I get caught speeding I would man up and take the ticket without complaint. After all I was the one speeding and the officer is just doing his or her job.
This post has been edited 3 times, most recently by 11B2P 20 months ago
Doc I would take my foot off the gas too. The officer has to make a determination on which car had the highest speed. The radar only displays the fastest speed.
Slowing down may save you...because the officer is LOOKING for clues to determine which car is driving the fastest. The other car moving ahead of yours may work. Try to remember to not slam on the brakes. The nose dive is a dead give away.
Above all if you are pulled over remember to be respectful. The officer is just doing their job. Some are going to be dicks to you but there are dicks every where in the world. Arguing won't change anything on the side of the road.
The Valentine One works very well. It is not a magic bullet, but in most instances will give you plenty of warning.
I've seen some really cool in-dash installations that have been done with the V1.
each dept is different. for our department, we are not allowed to right anyone a speeding ticket that is going 7 over or less. we also record the speed for 3 seconds to make sure we do not get an erroneous reading. you also have to take into account what kind of road you are traveling for that decision of which car is moving fastest.
there is a lot of math involved in radar so i wont bore you to death with it all. i also do not use LIDAR which other cops may use just because i dont have the time to do much traffic stuff. but the radar i use has 3 settings. i can use it as stationary, figure out the speed of the vehicle in front of me, or the vehicles that are opposing me.
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