When does photo radar measure speed?

[frozenrice]

I'm just curious as to when photo radar actually measures your speed. Is it as you are approaching (if so by how close) or after you've passed? I passed one going up Sarcee Trail South. I slowed as I approached it but I'm not sure if soon enough.

[GTS Jeff]

to my knowledge, it measures your speed as u approach, then estimates when to snap the pick when ure leaving. i always slam on my brakes when i see photo radar so itll take the pic at te wrong time. im sure ppl behind me find it annoying, but ive never gotten a photo radar ticket and i probably saved their asses from one too.

['93 SR-V]

I would have thought that it measures once you are infront. (I don't know this for sure). The reason I say this is because I have come up on them many times and hit the brakes in time to avoid a ticket and have never seen a flash go off infront of me as a result. Also, the camera and the radar would have to be aimed at the same place, so if the radar is facing the back and the camera is facing the front, it could cause problems if the road was curving or the van / truck wasn't exactly parallel to the road.

[Arriviste]

As far as I know, it measures your speed after you have passed the vehicle. It measures your speed and takes the photo much faster than a person doing the job manually could, thereby giving it the ability to calculate speed and take the picture in the fraction of a second that you pass by. As long as you are not speeding as you pass the drivers side window of the photo vehicle, I believe you are alright. I know that I pass a photo radar vehicle at least 2-3 times a week on Sarcee Trail just North of Bow Trail, and have never gotten a ticket even though I regularily go 100km/h untill very near the van, then slow down, and resume 100km/h 100 Meters past. I have yet to get a ticket from photoradar, and I continually brake closer to the van trying to figure out exactly how close I can come without getting a ticket. It sounds stupid, but someone may aswell figure it out. Also remember that photo radar typically gives you a buffer of between 7-12km/h over the limit depending on the posted speed limit on the road in question. Hope this helps!:thumbsup:
PS, I know for a fact that pretty much as soon as you pass the vehicle, you can step on the gas and resume your normal cruising speed without getting a ticket. The only moment that counts, is the one as you pass the drivers side window.
:burnout:

[ryder_23]

Originally posted by GTS Jeff
to my knowledge, it measures your speed as u approach, then estimates when to snap the pick when ure leaving. i always slam on my brakes when i see photo radar so itll take the pic at te wrong time. im sure ppl behind me find it annoying, but ive never gotten a photo radar ticket and i probably saved their asses from one too.

There is 2 photo radar versions.

The majority in canada, measures ur speed right after you pass it, and takes picture right after.

The other, clocks your speed as you approach, and calculates where you will be with your speed, and times it as you pass to take photo. This can be avoided by going say 100 in a 50, down to like 30k, it will snap photo before.

This other version is used in the us, i've never seen this version in canada yet. I believe it was the first photo radar technology (clocking before you pass).

[GTS Jeff]

Originally posted by ryder_23


There is 2 photo radar versions.

The majority in canada, measures ur speed right after you pass it, and takes picture right after.

The other, clocks your speed as you approach, and calculates where you will be with your speed, and times it as you pass to take photo. This can be avoided by going say 100 in a 50, down to like 30k, it will snap photo before.

This other version is used in the us, i've never seen this version in canada yet. I believe it was the first photo radar technology (clocking before you pass). holy shit, so it doesnt matter at all if ure speeding when u are in sight of the van?

[davidI]

Today I saw a photo radar van and noticed that the back bottom left corner of the rear windshield was wiped clean (the rest had dirty and spray on it from the roads). At the time I knew there had to be a reason for them to clean that little section of the window so maybe the vans in calgary do measure you on your approach.

[HTN SWCHS]

i heard photo radar is a private company contracted by the government and paid a lump sum depending on how much revenue they bring in

[davidI]

Originally posted by HTN SWCHS
i heard photo radar is a private company contracted by the government and paid a lump sum depending on how much revenue they bring in

Why is there always a cop sitting next to the machine then?

[kenny]

Originally posted by davidI


Why is there always a cop sitting next to the machine then?

Guess who shows up in court when you goto fight the ticket ;) Every time a picture is taken, the guy in the van (not a cop) will take notes.

[davidI]

Originally posted by kenny


Guess who shows up in court when you goto fight the ticket ;) Every time a picture is taken, the guy in the van (not a cop) will take notes.

So it is a private company?

I know why the guy is there but I always thought they looked like they were wearing a police uniform...so it wouldn't be a private company doing it...

['93 SR-V]

Yes, it's private

[lint]

This is info that I got talking to a cop a few years ago about the workings of Multi-Nova.

The machine is mounted on the front of the car/van and sends a radar beam out over the road that can cover all 3 lanes (hiding in the fast lane doesn't help). It does extend out in front of the car/van, not behind. The beam is able to measure your speed when you enter and when you exit. (I can't remember how wide the beam is) In order for it to get an accurate measure of speed, there can only be a difference of +- 3% when you exit vs when you enter the beam. What this means is that you can either brake hard when you're passing the car/van and entering the beam or you can hit the gas hard. As long as your entering and exit speeds differ by > +-3% then the camera may take your picture, but the speed that's recorded on it will be zero'd out, and will be useless. The cop I talked to was telling us that he was clocking at the bottom of a hill and a bike flew past going way over the limit, but because he was still accellerating, a pic was snapped with no speed registered.

Same thing happens if there is more than one car in the beam at a time. It can't distinguish which car to measure, so if another car enters the beam before you exit, again a pic can be snapped with no speed. I think it was something like if there's 15 ft between you and the car in front of you.

Don't worry about photo radar during rush hour, there's too much traffic for it to work. Be careful in the lull right after though, when fewer cars are on the road, and it's easier to be caught alone in the beam. Brake hard, gas it hard, and you should be fine, same with driving next to another car, or close behind.

[sillyd]

By the way it's Multanova, not multinova.

[FiveFreshFish]

Originally posted by lint
Don't worry about photo radar during rush hour, there's too much traffic for it to work.

I see them out during rush hour all the time, but they're shooting the cars going the opposite way of the heavy traffic.

Sneaky bastards.

[lint]

Originally posted by FiveFreshFish


I see them out during rush hour all the time, but they're shooting the cars going the opposite way of the heavy traffic.

Sneaky bastards.

In those cases, they're just there as a presence to deter speeding. There is no way that the multanova can catch anyone in heavy traffic. Camera will flash like crazy though.

[?????]

Originally posted by lint


In those cases, they're just there as a presence to deter speeding. There is no way that the multanova can catch anyone in heavy traffic. Camera will flash like crazy though.

He said "opposite way" of heavy traffic..they do this on 14st.

[lint]

Originally posted by ?????


He said "opposite way" of heavy traffic..they do this on 14st.

Ok, misunderstood the question. My point is still you don't have to worry when you're in traffic. When you're lonely on the roads, be alert.

[Khyron]

The forward pointing radar seems to be KA instant on radar. So if you are the only guy on the road, the detector probably won't get a reading until you are being zapped. If there's people in front of you, you can get a reading. But yah, I don't slow down until I'm almost beside the van.

Khyron

[ryder_23]

Originally posted by Khyron
The forward pointing radar seems to be KA instant on radar. So if you are the only guy on the road, the detector probably won't get a reading until you are being zapped. If there's people in front of you, you can get a reading. But yah, I don't slow down until I'm almost beside the van.

Khyron

Its a version of Ka with a very thin beam. Its hard to pick up, and its not instant on radar. The radar beam is always on. You can still pick it up with a good radar detector in advance, usually only if theres alot of people ahead of you, just like you said.

[frostyda9]

Originally posted by FiveFreshFish

Sneaky bastards.

They can be....the place that pissed me off was when I was heading east on Richmond road and the cop was parked on the road that parallels Richmond, in between a line of parked cars. I've seen them do that on Bow Trail too...you have to keep an eye out.

[BlueGoblin]

Originally posted by '93 SR-V
Yes, it's private

Actuallly, they are neither private, nor are they police officers. The multanova operators are city employees with Special Constable status. They work much in the same way that bylaw enforcement officers do.