Photo Radar at Traffic Lights [MRG]

[MaxPower]

Originally Posted by BlackArcher101

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

That makes sense, I didn't know they had pairs of loops. The first post I saw mentioning loops said they worked by measuring the time the vehicle was in the loop.

[skins]

Originally Posted by MaxPower

That makes sense, I didn't know they had pairs of loops. The first post I saw mentioning loops said they worked by measuring the time the vehicle was in the loop.

Ya, I was just recalling what I vaguely remembered from an ITS presentation in my transportation engineering class a few years back. You would need two loops to detect speed. I remember the presenter showing us some pictures taken from red light cameras and they did log the speed of the vehicle.

I'm pretty sure all red light cameras are equipped with two loops and here's why: with a single loop, you don't know if the vehicle was slowing down to stop or speeding up to beat the light. If some one slams on their brakes to stop before the light changes the camera could go off. If they know the vehicle's speed, then they know whether or not the person was in the process of slowing down. This happened to me at the lights on Sarcee & Richmond Road. I slammed on my brakes (knowing there was a red light camera). Almost immediately after stopping, the flash went off. Never got a ticket.

Regarding the accuracy, if the loops are spaced very close together (ie. side by side) I think you would get a very accurate measurement of speed. sure it would be the average over the distance, but how much can a car speed up or slow down in a space of 6-8 feet when it's already going 70+ km/h?

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 wouldn't matter. As soon as the front of the vehicle enters the loop, it's presence can be detected. so whether the vehicle is 6 ft or 30 ft long it wouldn't make a difference. If that didn't work, remember that they have a picture of the vehicle as well.

[MaxPower]

Originally Posted by skins

ya, I was just recalling what I vaguely remembered from an ITS presentation in my transportation engineering class a few years back. you would need two loops to detect speed. I remember the presenter showing us some pictures taken from red light cameras and they did log the speed of the vehicle.



I don't think that matters. as soon as the front of the vehicle enters the loop, it's presence is detected. so whether the vehicle is 8 ft or 30 ft long
it wouldn't make a difference. if that doesn't work, remember that they do have a picture of the vehicle as well.

You realize both your quotes are from me right? And that I agree with you if there's two loops. But if there's only one, then I'm pretty sure size of the vehicle matters considerably.

[Fobby]

Back to this photo radar at the light thing. IMHO, i don't think it's a good idea due to the fact that many people are going to slam on their brakes to make sure they are going below the speed limit just to make sure that they are not going to get caught.

this will totally kill the flow of traffic, normally going 55 which is acceptable, but when someone sees the photo radar or red light camera sign, everyone, and I mean, everyone WILL brake, go make sure they go either right at 50.. or even below so they don't get caught..

to me... i don't know how this isn't a cash cow. I think this will also increase the number of rear end collision. At least the red light camera.. you have to pass both lines when the light is red.

[Bagor]

Thousands of drivers in Italy are expected to seek compensation after it was revealed that a system to catch them jumping red lights was rigged.
More than 100 people, including police officers, are being investigated as part of the fraud..........

.....But it is now claimed the lights were rigged to change from yellow to red in three seconds instead of the regulation five or six seconds.
The fraud was uncovered by a senior police officer who noticed an unusually high number of fines being issued.
Instead of an average 15 fines a day in some places, the figure jumped to more than 1,000.
The fraud may have netted as much as $170m (£116.4m) for those involved.

http://news.bbc.co.uk/2/hi/europe/7862893.stm

[4X4]

Lol. Since when do they enforce red lights in Italy?!? I used to have a blast running red lights. One day I cut off a cop who had the green, and I ran the red and all he did was wag his finger at me. Italy rocks!

[BlackArcher101]

5 or 6 seconds? Damn, that must be nice! Whenever I'm in Calgary or Edmonton I can't beleive how short the yellows are, gotta be 2 seconds at the most. Here in Red Deer they almost seem double the length at I'm guessing 3-4 seconds.

[GGG]

I don't have a link a guy at the U of C did a study on it but some of the results of photo radar and red light radar are:

Red Light Radar
Increased Rear End Colisions
Decrease in other catagoires of collisions
Reduction in injuries

Speed Radars
Reduce over all speed

So all in all there are benefits to photo radar. I hate the tickets but if you believe that reductions in speed reduce losses in life which is statistically proven then phot radar is a good thing. I think though all revenues from the tickets should go directly into the police budget instead of into general revenues. At least then you could feel good about where your money went

[JustAnotherGuy]

How many times have you put the brakes on to stop at a intersection where the light just turned amber and you hear the person behind you accelerating? LOL

[REDVAN]

Originally Posted by JustAnotherGuy

How many times have you put the brakes on to stop at a intersection where the light just turned amber and you hear the person behind you accelerating? LOL

I see that you're one of those people... just stay out of my left lane

[driveway]

Originally Posted by BlackArcher101

5 or 6 seconds? Damn, that must be nice! Whenever I'm in Calgary or Edmonton I can't beleive how short the yellows are, gotta be 2 seconds at the most. Here in Red Deer they almost seem double the length at I'm guessing 3-4 seconds.

Really? Moving here from Victoria I was stunned at the length of yellows in this town. Also, in Victoria, yellows are synched with the walk/don't walk light. As soon as the 'don't walk' stops flashing and turns solid, the yellow comes on.

I actually quite like that, because it gives both drivers and pedestrians more indication of how long they have before the light changes.

[La Flames Fan]

Originally Posted by Kerplunk

I'm just waiting to see when they will install an ANPR system like they have in England. Set one up on Deerfoot and watch the cash flow in.

I wouldn't mind photo radar on Deerfoot. Higher speeds, bigger idiots, more at stake. They would probably catch a whole lot more speeders make oodles more money on Deerfoot too.

[JustAnotherGuy]

Originally Posted by REDVAN

I see that you're one of those people... just stay out of my left lane

I am not one of those people. Well, I don't think I am. Light turns amber I quickly judge if I will make it through the intersection before the light turns red. If I will make it through then I continue on my way. If not I slow down and stop.

Are you one of THOSE people that accelerates when they see amber?

[Russic]

The amber lights in Calgary are probably close to 5 seconds aren't they? They are usually long enough for my wife and I to have this conversation:

Wife: are you going to stop?
me: nope
Wife: But it's going to turn red.
me: no it isn't
Wife: Jesus!
me: * as we pass under it * aaaaaaand still yellow

[FlameCity]

From the Sun today:

Beginning April 1, so-called speed on green cameras will be ticketing Calgarians speeding through several dozen intersections in the city.

Link to Story

[Rathji]

Just got this list chain emailed to me, thought it might be useful

Here is a list of the 44 intersections that have the new speed on green cameras. Until April 1st, you will only get a warning.

Macleod Tr / 162 Av SE
Macleod Tr /12 Ave SE
Centre St/ 20 Ave N
John Laurie Bv / 53 St NW
68ST /16 Ave NE
Sarcee Tr / Richmond Rd SW
4 St / 6 Ave SW
61 Ave / Barlow Tr SE
Crowchild Tr / 24 Ave NW
11 Ave / 4 St SW
11 Ave / 14 St SW
17 Ave / 44 St SE
14 St / Heritage Dr SW
14 St / Northmount Dr NW
64 Ave / 4 St NE
Anderson Rd / Acadia Dr SE
9 Ave / 11 St SW
Barlow Ttr / 32 Ave NE
52 ST / 32 AVE NE
Bowness Rd / Shaganappi Tr NW
Canyon Meadows Dr / Bowbottom Tr SE
Southland Dr / Acadia Dr SE
Fairmount Dr / Southland Dr SE
Elbow Dr / Southland Dr SW
Beddington Tr / Centre St N
Falconridge Bv / 64 Av NE
1 Street / 17 Ave SE
McKnight Bv / Barlow Tr NE
Barlow Tr / Centre Av E
Shaganappi Tr / Northland Dr NW
Blackfoot Tr / 42 Ave SE
Memorial Dr / 52 St NE
16 Ave / 10 Street NW
Edmonton Tr / McKnight BV NE
Memorial Dr / 28 St NE
Macleod Tr / 7 Ave SE
Bow Tr / 33 St SW
17 Ave / 33 St SW
Elbow Dr / Heritage Dr SW
Country Hills Bv / Beddington Tr NW
Glenmore Tr / Barlow Tr SE
McKnight Bv / Falconridge Bv NE
Macleod Tr / 25 Av SE
Country Hills BV / 14 St NW

[albertGQ]

^^^

What does the bolded intersections mean?

[Rathji]

I just cut and paste, didnt notice the bold

[worth]

So I can say that I was wrong about the cameras using radar. They will indeed use a timed circuit at either end of the intersection. So unless you have a 9500xi radar detector that had GPS and locations of red light cameras, your radar detector will not alert you to these traps. You will just have to slow down through the intersection.

http://74.125.95.132/search?q=cache:...ient=firefox-a

[jayocal]

Bottom line. If people stop driving like idiots and quit smashing into s**t and each other, the government would not have the outrageous traffic statistics to "justify" their actions.

For work, I drive, on average, 200-300km a day within Calgary city limits and let me tell you, it's not pretty out there! Every single day is a new adventure.