Mass sensors at traffic lights

[SeanB]

Sounds like the vendors here........

[deth502]

Here since the 1980's they connected most of the signals to a central control room with an upgrade to a computerised control for each intersection. This replaced the old Automotor controls, of which a few are still left running small intersections. That way they can remotely program light duration and have traffic pattern control.

all of ours are independent, due to the distances that they are apart.

there is no "control room", but the spec is (state law in my state, ymmv) that if the signals are less than x amount apart, they must be connected to a common controller to synchronize them for better traffic flow. still all computer controlled and autonomous though.

actual power consumption differences between both methods, i cant say, i dont pay the electric bills, and im not privy to that financial information, but under the guise of reduced power consumption, we were mandated to retrofit all of our incandescent bulb signals to led's a few years back.

[GiskardReventlov]

Now the difficult part is that the loop inductance will slowly vary naturally with temperature and even atmospheric pressure. You need algorithms to filter out the slow changes but detect the large changes.

For bicycles you can do the same thing but the loop needs to be smaller and two loops can be used to increase sensitivity.

Sounds like you'd need to calibrate the device for each intersection. 

Most intersections don't trigger for a bicycle and even motorcycles have problems too. I think this answers my question about implementation.  If they don't add small loops then smaller vehicles don't trigger. This presents a
dilemma because smaller vehicles can get stuck at red lights that don't "see" them.

[StevenB]

So you replace a reliable simple low cost low power sensor with a new one that is both complex, high power use and likely to give problems down the line with failing electronic systems, along with not being reliable in heavy rain, snow and with direct sunlight hitting the camera lens.

I smell pork pies there.

I don't understand why the simple inductive system is being replace by cameras either.  I assume it is easier to maintain and adjust?  I have definetly seen issues during fog (have to sit throught each cycle timing out instead of detecting no cars).  I imagine this is a calibration issue.  It's fustrating when you are late for work!

[Yago]

In UK it looks like there are cameras appearing at the top of traffic light junctions and crossings.
Might be that our roads are so knackered that any loops etc are just being pulled apart as the road fails. I don't think that what we have qualifies as just pot holes now!

[GiskardReventlov]

In UK it looks like there are cameras appearing at the top of traffic light junctions and crossings.
Might be that our roads are so knackered that any loops etc are just being pulled apart as the road fails. I don't think that what we have qualifies as just pot holes now!

Some places put up fake cameras. If they can't afford to fix pot holes they either use fake cameras or they spent all the money on real cameras and can't fix the pot holes.

I heard that vandals have used lasers on cameras to burn out the image sensor. Not sure if that's true but I think it's possible. But preventable I'd think.

[SeanB]

Here they just shoot them or necklace them. You need a guard for the camera or it will be towed till it falls apart. I see the local metro are trialling a vehicle sensor, but this one is a simple microwave vehicle sensor rather than a vision system. They are also at the same trial intersection trialling some countdown times LED lamp units, which do look quite nice with the animated pedestrian in green with the orange countdown above it.