Photo radar question

kevinhits · #1 04-13-2021, 09:55 AM

Hey all,

So, driving down Deerfoot this morning, i come across a photo radar vehicle travelling in the left lane going 100KM and decided to pass him. I was increasing my speed and looked back to see a flash. Is this even legal or possible? Never heard of this ever before happening to anyone.

Thoughts?

Sooner · #2 04-13-2021, 10:12 AM

Legal, who knows what the cities allow. They seem to be ok with pylons on a busy bridge or hide behind bushes or bus shelters here in Edmonton.

I would wonder how both traveling at similar speeds could get an accurate reading on your speed(assuming you think it was you that set it off). Maybe the sensor was still activated and you triggered the flash. I guess you wait for the surprise in the mail.

Seems like an easy one to beat if you do get it.

elkhunter11 · #3 04-13-2021, 10:27 AM

That is interesting given that you mention the photo radar vehicle was traveling in the left lane. The photo radar cameras are angled to the left at around 20-23 degrees, so if you passed on the right side, you likely weren't even in the beam.

KGB · #4 04-13-2021, 10:49 AM

It wasn’t probably even a flash that you have seen but rather the sun reflection.

EZM · #5 04-13-2021, 10:59 AM

Bad news is …. it's not that technical or complex for todays laser technology to determine your speed of travel accurately even if the camera vehicle is also moving.

Bad news is ….. it's probably perfectly legal, and you were speeding so if this is the case, you will likely get the ticket

I haven't seen this before, and it sucks to see they are doing that - travelling slow in the left lane to force people to pass you could be a form of entrapment IMO - not sure if the judge would agree with me though.

ATF · #6 04-13-2021, 10:59 AM

Maybe they can manually trigger the flash. Probably a feeble attempt at shaking his finger at you for passing him.

kevinhits · #7 04-13-2021, 11:02 AM

Quote:

Originally Posted by elkhunter11

That is interesting given that you mention the photo radar vehicle was traveling in the left lane. The photo radar cameras are angled to the left at around 20-23 degrees, so if you passed on the right side, you likely weren't even in the beam.

Sorry my bad, he was in the right lane and I was in the left...

kevinhits · #8 04-13-2021, 11:03 AM

Quote:

Originally Posted by ATF

Maybe they can manually trigger the flash. Probably a feeble attempt at shaking his finger at you for passing him.

I was thinking the same thing..LOL

He looked a little grumpy as I passed

kevinhits · #9 04-13-2021, 11:05 AM

Quote:

Originally Posted by Sooner

Legal, who knows what the cities allow. They seem to be ok with pylons on a busy bridge or hide behind bushes or bus shelters here in Edmonton.

I would wonder how both traveling at similar speeds could get an accurate reading on your speed(assuming you think it was you that set it off). Maybe the sensor was still activated and you triggered the flash. I guess you wait for the surprise in the mail.

Seems like an easy one to beat if you do get it.

This was my main concern is how exactly they can do it travelling at similar speeds. I also thought about fighting it if something does come in the mail..LOL

elkhunter11 · #10 04-13-2021, 11:06 AM

Quote:

Originally Posted by kevinhits

I was thinking the same thing..LOL

He looked a little grumpy as I passed

It probably takes a grumpy person to do that job.

kevinhits · #11 04-13-2021, 11:07 AM

Quote:

Originally Posted by KGB

It wasn’t probably even a flash that you have seen but rather the sun reflection.

Nope, definetly a flash.

does it ALL outdoors · #12 04-13-2021, 11:07 AM

Wouldn't surprise me one bit if they are taking the show on the road.

The operator can flash the light anytime he wants, just honk at a stationary photo truck or van and there's a good chance they will flash the light at you. It's just a scare tactic. I honk at them all the time.

My guess is that's what happened.

If they are taking the show on the road it's easy for them to tell how fast your going, cop cars have had them for years that tell the differentiated speed, it figures how fast your going while taking into account how fast the cop car is going. It's old technology.

Pretty sure all RCMP cars have them, that's how they clock you when going the opposite direction as you on the highway.

kevinhits · #13 04-13-2021, 11:11 AM

Quote:

Originally Posted by elkhunter11

It probably takes a grumpy person to do that job.

HAHAHA...True dat

bat119 · #14 04-13-2021, 11:32 AM

Strikes fear in the hearts of the speeders LOL

They were talking about moving radar few years ago I thought it was struck down now with the deficit the way is is they might be looking at more revenue.

Like shooting fish in a barrel

CNP · #15 04-13-2021, 11:35 AM

Their job is to record vehicles exceeding the speed limit. I don't know why it wouldn't be legal. It's certainly possible.

Koschenk · #16 04-13-2021, 11:42 AM

New radars can detect your speed whether you're approaching from behind the vehicle, passing, or headed towards eachother. Found this out the hard way, annoyingly on hwy 40 with about 300m of pavement left before it went gravel.

elkhunter11 · #17 04-13-2021, 11:48 AM

Regular radar units have two antennas that allow them to track two speeds, including the speed of the vehicle the radar unit is in. These radar units are also aimed directly forward or rearward, as they are designed to measure the speed of vehicles pretty much in line with them.

Photo radar units are made to be used while stationary, so they don't need a second antenna, to measure a second speed. As well, the camera is angled around 20-23 degrees to the left, since the photo radar vehicle often parks in parking lots, well back from the street. So if photo radar was to be used in a moving vehicle, they would need to design a unit for this.

Koschenk · #18 04-13-2021, 11:49 AM

New radars can detect your speed whether you're approaching from behind the vehicle, passing, or headed towards eachother. Found this out the hard way, annoyingly on hwy 40 with about 300m of pavement left before it went gravel.

jednastka · #19 04-13-2021, 03:08 PM

The technology has been available for at least 20 years. One unit accurately determines the radar car's speed, usually by aiming at the road just in front of the vehicle. Second unit measures your speed relative to the radar car's speed. Add the two units together gives your speed. Done deal.

kevinhits · #20 04-13-2021, 03:32 PM

Quote:

Originally Posted by jednastka

The technology has been available for at least 20 years. One unit accurately determines the radar car's speed, usually by aiming at the road just in front of the vehicle. Second unit measures your speed relative to the radar car's speed. Add the two units together gives your speed. Done deal.

I am talking about a photo radar vehicle travelling from one location to another. Not a police radar gun in the vehicle while doing there patrols.

dodger · #21 04-13-2021, 05:36 PM

Keep us posted and how much $

Dodger.

Ken07AOVette · #22 04-13-2021, 05:48 PM

Quote:

Originally Posted by kevinhits

I am talking about a photo radar vehicle travelling from one location to another. Not a police radar gun in the vehicle while doing there patrols.

How do you know he was going from one to the next? Are you sure they have not implemented roving photo radar? I was on the Henday yesterday and got a warning about 'mobile speed camera ahead' that came from my phone I was using for navigation.

kevinhits · #23 04-13-2021, 05:51 PM

Quote:

Originally Posted by dodger

Keep us posted and how much $

Dodger.

Will do...

kevinhits · #24 04-13-2021, 05:53 PM

Quote:

Originally Posted by Ken07AOVette

How do you know he was going from one to the next? Are you sure they have not implemented roving photo radar? I was on the Henday yesterday and got a warning about 'mobile speed camera ahead' that came from my phone I was using for navigation.

I am assuming so Ken. I guess I will have to wait for the mail..LOL

elkhunter11 · #25 04-13-2021, 06:01 PM

Quote:

Originally Posted by Ken07AOVette

How do you know he was going from one to the next? Are you sure they have not implemented roving photo radar? I was on the Henday yesterday and got a warning about 'mobile speed camera ahead' that came from my phone I was using for navigation.

The photo radar cameras do not work like police radar, in that they can only track one speed, the speed of the target. The police radar has two antennas, so it can track the target, and the speed of the vehicle that it is in. As well, the photo radar cameras sit at about a 22 degree angle in the vehicle, so they can can park well off the street and still track passing vehicles. The readings they produce are based on that angle, so if they are mobile and in a curve, the readings could have considerable error due to cosine angle. And unlike police radar that is aimed straight ahead, cosine error with a camera mounted at an angle can cause a reading that is higher than actual. So even if they could track two speeds, there would be a lot of room for error. If they want to come up with a moving unit,they would have to design a complete new unit just for mobile applications, and as of yet, that hasn't happened.

CNP · #26 04-13-2021, 06:06 PM

https://www.calgary.ca/cps/traffic/photo-radar.html

Jack Hardin · #27 04-13-2021, 09:02 PM

Quote:

Originally Posted by jednastka

The technology has been available for at least 20 years. One unit accurately determines the radar car's speed, usually by aiming at the road just in front of the vehicle. Second unit measures your speed relative to the radar car's speed. Add the two units together gives your speed. Done deal.

Longer than 20 years ago. I was running radar back in the '90s, and I had that capability.

ccmckee · #28 04-14-2021, 07:17 AM

Quote:

Originally Posted by Sooner

Legal, who knows what the cities allow. They seem to be ok with pylons on a busy bridge or hide behind bushes or bus shelters here in Edmonton.

I would wonder how both traveling at similar speeds could get an accurate reading on your speed(assuming you think it was you that set it off). Maybe the sensor was still activated and you triggered the flash. I guess you wait for the surprise in the mail.

Seems like an easy one to beat if you do get it.

They have been doing mobile readings for years with the car mounted radar units, can't see it being any less effective with the photo radar.

58thecat · #29 04-14-2021, 07:23 AM

I did this once...crawled up on a unmarked cop car....passed and got lite up...yup...ticket too

.....cop said what were you thinking as I said I knew it was a unmarked car but yet still passed....should have just hunkered back and let another fool take the lead

ohh well life lessons some just learnt the hard way

elkhunter11 · #30 04-14-2021, 07:28 AM

Quote:

Originally Posted by ccmckee

They have been doing mobile readings for years with the car mounted radar units, can't see it being any less effective with the photo radar.

You need to look at the differences between police radar, and photo radar cameras, they were designed for different applications, so they have different capabilities.