Photo Radar at Traffic Lights [MRG]

[Crazy Flamer]

Originally Posted by Incinerator

someone should invent an electronic "hide-a-plate" device, you push a button when you get to the intersection and the plate tucks away into the trunk, the pops back out when you press the button again after the intersection

Dragon's Den, here I come!!!

[BlackArcher101]

Originally Posted by skins

I'm pretty sure the speed is recorded by the sensors embedded in the asphalt. It's a loop of wires under the road that can tell when a car is moving through (ie. if the car is moving into the intersection when the light is red). these loops can also very accurately detect how long the vehicle is inside the loop (ie. it's speed).

no radar. no new infrastructure.

In fact, I think the accuracy might be even better than radar.

I believe that if the speed is in fact detected via the loops, it is less accurate. This is because two loops are required spaced a certain distance apart. The speed it comes up with is actually the average between the two loops, not an instantaneous speed which is what radar is closer to. Similar to the method used back in the day when aircraft measured your speed, just a smaller scale. I don't see them using actual radar though as they would need it for each lane and the cost would be insane. Irregardless, this wouldn't benefit us as the speed it shows will be lower than the actual max speed you were traveling at.

[toonmaster]

Originally Posted by skins

I'm pretty sure the speed is recorded by the sensors embedded in the asphalt. It's a loop of wires under the road that can tell when a car is moving through (ie. if the car is moving into the intersection when the light is red). these loops can also very accurately detect how long the vehicle is inside the loop (ie. it's speed).

no radar. no new infrastructure.

In fact, I think the accuracy might be even better than radar.

bang on, instead of the cameras being active only when the light turns red, they are now active while the light is green. they have a loop, the distance between parallel lines of this loop is know, if the time to cross this distance is less than the set threshold then bang, camera goes off and you are flashed.

at least thats how i understood the edmonton tests.

edit: i have to clue how accurate this system is, thats for calgary's TI department to know

[Thunderball]

Originally Posted by OzSome

Isn't amber or yellow light sufficient enough as a warning it might turn red? You can go on yellow if you have to. I go through the intersection you mentioned and never have problem with the said red light camera.

No one is disputing red light cameras... these ones are going to be at intersections regardless of red, green, stale green, fresh yellow or stale yellow. This one is going to cause accidents, and is only to make some money to keep the gravy train flowing. Stelmach's government is appalling.

[FireFly]

Just always say that you would not have been able to stop in a sufficent amount of time so you wanted to get out of the way for other drivers.

[Dion]

Charlie Pester of Pointts was on the news tonight. Didn't have much good to say other than drivers who get these tickets should plead innocent and flood the court rooms

[worth]

Originally Posted by skins

I'm pretty sure the speed is recorded by the sensors embedded in the asphalt. It's a loop of wires under the road that can tell when a car is moving through (ie. if the car is moving into the intersection when the light is red). these loops can also very accurately detect how long the vehicle is inside the loop (ie. it's speed).

no radar. no new infrastructure.

In fact, I think the accuracy might be even better than radar.

That sensor is an inductive loop which completes the circuit when a car is on top of it changing the light like you said.

The infastructure is already in place with the red light cameras, they will add a Ka band radar station with every red light camera.

The inductive loop you see on the road has nothing to do with clocking speed, and it's not in parallel, it's a circuit, or a rectangle. you can see them at the intersection of 84th street and glenmore trail se. they mark the spot and come back to install the loop after the asphalt has been laid.

do you guys have any documentation that the inductive loop determines speed, because I have never heard of this before...

[BlackArcher101]

Originally Posted by worth

That sensor is an inductive loop which completes the circuit when a car is on top of it changing the light like you said.

The infastructure is already in place with the red light cameras, they will add a Ka band radar station with every red light camera.

The inductive loop you see on the road has nothing to do with clocking speed, and it's not in parallel, it's a circuit, or a rectangle. you can see them at the intersection of 84th street and glenmore trail se. they mark the spot and come back to install the loop after the asphalt has been laid.

do you guys have any documentation that the inductive loop determines speed, because I have never heard of this before...

Interesting... how will the radar be able to tell which car was speeding? Are they going to have one for each lane in each direction?

I'm 90% sure I've seen the loops being use for speed detection, I'll have to do some searching on the net for it a little later.

[Tower]

Start Paintballing Cameras!!!!

[worth]

Originally Posted by BlackArcher101

Interesting... how will the radar be able to tell which car was speeding? Are they going to have one for each lane in each direction?

I'm 90% sure I've seen the loops being use for speed detection, I'll have to do some searching on the net for it a little later.

I would think it would be exactly like how Multinova Photo Radar works now. We all see those silver vans parked in the most conspicuous places on Calgary's roads. They use Ka band radar to determine your speed by bouncing radar off your car. The doppler shift, or how much the radar changes when it is received back gives the speed of the car.

Ka Band is easy to pick up with any detector. RCMP will leave their mobile Ka band on all the time while driving, and I have even picked up the new Sheriffs with Ka band on inside the city. So don't speed if you're going by a sheriff.

Using the loop as speed detection is interesting...I will have to search around a bit.

[V]

Originally Posted by skins

I'm pretty sure the speed is recorded by the sensors embedded in the asphalt. It's a loop of wires under the road that can tell when a car is moving through (ie. if the car is moving into the intersection when the light is red). these loops can also very accurately detect how long the vehicle is inside the loop (ie. it's speed).

no radar. no new infrastructure.

In fact, I think the accuracy might be even better than radar.

This is completely false.

[BlackArcher101]

Originally Posted by V

This is completely false.

What is, the capability of loops to determine speed or the claim they are more accurate than radar.....

[Ironhorse]

I thought the loops were there for the sole reason of detecting traffic flow / volume. They're probably not accurate enough for anything else.

[Madman]

Originally Posted by jolinar of malkshor

For roads with speeds over 60k there should be warning lights to let you know that it is changing.

Why not make street lights on public roads function like they do on 7th Ave? Where the light is green and then the green stays on and the yellow starts to flash to give a warning about the impending change.

[Madman]

Originally Posted by worth

Multinova

MultAnova



[pet peeve #12]

[MaxPower]

The loops do not detect speed. The size of the vehicle would have a huge effect on how long the loop detected it. A semi hauling a trailer could barrel through pretty fast and look like a SMART car rolling through at a much slower speed. Does not work.

[FlamesAddiction]

Originally Posted by Pagal4321

###

I still find it odd that bigger cities such as Vancouver and Toronto don't even HAVE photo radar....but yet here we are attaching it to red light camera's.
What's next?

Vancouver had it for a while. My sister racked up a pile of tickets that way. She never did pay them and the program was cancelled by the Campbell government and all current tickets were cancelled.

Campbell was elected on the promise to get rid of photo radar.

[metallicat]

How about you guys just slow down at intersections, and then speed back up to your un-Godly velocities after that? Make things a little safer in our cities...?

[BlackArcher101]

Originally Posted by MaxPower

The loops do not detect speed. The size of the vehicle would have a huge effect on how long the loop detected it. A semi hauling a trailer could barrel through pretty fast and look like a SMART car rolling through at a much slower speed. Does not work.

That's true for a single loop. But when you have two loops spaced apart they can.

[Bill Bumface]

Originally Posted by worth

That sensor is an inductive loop which completes the circuit when a car is on top of it changing the light like you said.

The infastructure is already in place with the red light cameras, they will add a Ka band radar station with every red light camera.

The inductive loop you see on the road has nothing to do with clocking speed, and it's not in parallel, it's a circuit, or a rectangle. you can see them at the intersection of 84th street and glenmore trail se. they mark the spot and come back to install the loop after the asphalt has been laid.

do you guys have any documentation that the inductive loop determines speed, because I have never heard of this before...

Originally Posted by V

This is completely false.

Originally Posted by Ironhorse

I thought the loops were there for the sole reason of detecting traffic flow / volume. They're probably not accurate enough for anything else.

Originally Posted by MaxPower

The loops do not detect speed. The size of the vehicle would have a huge effect on how long the loop detected it. A semi hauling a trailer could barrel through pretty fast and look like a SMART car rolling through at a much slower speed. Does not work.

The loops actually can be used for detecting speed. All you need is two loops a set difference apart, and you measure the time between peak or initial induction for each loop, and you have an accurate speed measurement. McLeod Trail North already has loops on either side of the intersection, but I believe that is only being used right now to time signals when the next block is full of traffic. I wonder if they'd have to change much?

http://en.wikipedia.org/wiki/Road_safety_camera

Vehicle-detection systems used in conjunction with road-rule enforcement cameras include the following:

• Piezo-electric strips - pressure-sensitive strips embedded in the roadway (a set distance apart if speed is to be measured - typically 1-3 metres).
• Doppler radar - a continuous radio signal is directed at a stretch of road, the vehicles and the change in frequency of the returned signal indicates the presence of a moving vehicle and the vehicle's speed.
• Loops - inductive loops embedded in the roadway detect the presence of vehicles, and with two loops a set distance apart vehicle speed can be measured.
• LIDAR - the time of flight of laser pulses is used to make a series of measurements of vehicle position, and from the series of measurements vehicle speed can be calculated.
• Automatic number plate recognition (ANPR) systems that use a form of optical character recognition to read the vehicle's licence or registration plate.