Traffic lights

[Bet51987]

I am out of school for the summer, but still taking driving lessons. My question is why are stop lights so stupid?
Nobody is coming the other way, but I have to wait a full minute before it turns green. Longer if someone wants to cross the street. Don't get me wrong, I'm not an impatient person at all, I just don't get it with the price of gas that I have to wait.

It would seem much better to have lights with brains so traffic can flow smoothly. I didn't tell my instructor.....I'm very cautious what I say in front of him.

Another thing....what trips the lights when you drive over a certain part of the road?

Bettina

[Pun]

Proximity sensors in the road. it's a loop of wire basically.

[Grendel]

Nobody is coming the other way, but I have to wait a full minute before it turns green. Longer if someone wants to cross the street. Don't get me wrong, I'm not an impatient person at all, I just don't get it with the price of gas that I have to wait.

Costs -- it's more expensive to outfit the light w/ sensors and a more complicated control unit.

Having a "special" rule for this situation (like "drive if it's free") wouldn't be a good idea, it would be abused and ppl would be killed.

Another thing....what trips the lights when you drive over a certain part of the road?

The metal of the cars body. Usually there are coils embedded in the pavement, if you drive over them some electronics detects the change in the coils inductive characteristic.

[Flatlander]

It would seem much better to have lights with brains so traffic can flow smoothly.

I couln't agree with you more. It could be worse, though. I can remember (back in the Stone Age) when traffic lights didn't have those sensors, they were just on a timer - really had to wait then

[woodchip]

It used to be that you could not turn right at a red light, then the powers that be decided allowing right hand turns would save the nation mucho gasoline.

[JMEaT]

We have sensors here on the lights that, at night, detect light from headlights and change as well as the sensors on the road.

[Mobius]

"Smart Lights" are only economic in areas with very high traffic flow.

Here in Christchurch, a local company is trialling a "super smart" light system with web cams. The Computer can recognise cars (and bicycles) approaching an intersection, and can calculate how busy each road is.

If you approach an intersection at 50 kmh, then it looks down the other streets, and if nothing is coming, it switches your light green for you.

[Flatlander]

If you approach an intersection at 50 kmh, then it looks down the other streets, and if nothing is coming, it switches your light green for you.

Sounds like heaven

[Testiculese]

lights with brains so traffic can flow smoothly

Lights are geared two ways. One way to smooth traffic, another to disrupt it.

The light sensors on most intersection in my area are geared to trip the red light on you when you are approching them. No one is coming the other way, there is *absolutely no reason* for the lights to trip. I have sat and timed several intersections at 1am, 2am, 3am...they stay green on the main road until a car comes, then they flip to red. This is for one of two reasons.

1) To waste gas and brakes by making people stop for no reason.
2) To bait people into different driving patterns for the police to monitor and make arrests.

Note these same intersections during the day never turn red unless someone comes to a stop at the smaller road of the intersection.

This is in the suburbs. In Phlly, the lights are mostly timed for traffic flow from the smaller roads to the arteries(Broad, Oregon, Market). There are few sensors installed in the city.

[Bet51987]

Funny, when dad was driving, I never noticed. Now that I'm taking lessons, I see all kinds of things.

I noticed a speed sign that says 30 MPH.......then a half mile farther another one says 35 MPH with a yellow sign underneath that says "Slow, Children Playing".

Why should you go faster? Geez, some things don't make sense.

Bettina

[Grendel]

Why should you go faster? Geez, some things don't make sense.

You don't -- the speed signs tell you the max. speed that you can go, hence "speed limit". Nobody says you have to drive that speed tho I think the german rule goes like "drive the speed that is appropriate for the situation but not faster than the speed limit".

[roid]

lights with brains so traffic can flow smoothly

Lights are geared two ways. One way to smooth traffic, another to disrupt it.

The light sensors on most intersection in my area are geared to trip the red light on you when you are approching them. No one is coming the other way, there is *absolutely no reason* for the lights to trip. I have sat and timed several intersections at 1am, 2am, 3am...they stay green on the main road until a car comes, then they flip to red. This is for one of two reasons.

1) To waste gas and brakes by making people stop for no reason.
2) To bait people into different driving patterns for the police to monitor and make arrests.

Note these same intersections during the day never turn red unless someone comes to a stop at the smaller road of the intersection.

This is in the suburbs. In Phlly, the lights are mostly timed for traffic flow from the smaller roads to the arteries(Broad, Oregon, Market). There are few sensors installed in the city.

that's weird stuff testi. is this just your theory or do other people suspect teh same thing... anything been done about it?

[Nitrofox125]

That *is* wierd. It would be really annoying too.

They've installed some new lights around here that seem to be really smart... they don't turn red unless there are a few cars waiting at cross streets, and there are *never* arrows unless there are cars waiting to turn. It's really nifty and going downtown where the lights are dumb or semi-smart is different.

[Stryker]

Here in Kansas, Olathe more specifically, street lights are midway-intelligent. They'll make you stop sometimes even if there's no other traffic in the area, but they'll usually flip to green after giving a yellow on the other lanes of traffic. You still have to stop, but you don't have to sit there for a normal light cycle.

[dissent]

Geez, some things don't make sense.
Bettina

Yeah, tell me about it. When I was (much *sigh*) younger, I used to think that grown-ups had everything all figured out, and that one day I'd be one of them. A modest eye-opener when I got to that state and found out that grown-ups were just making it up as they go along.

Don't let this happen to your kids !!!

[Testiculese]

Nope, it is absolute fact. I drive these roads all day every day. I know the light patterns for all of them. The one I used as an example is a major road (rt.320) with heavy traffic. Opposing traffic is an office building entrance, closed after 5pm, and the other side is a shopping center entrance (Staples, a clothing store, and misc.) which are all closed after, say, 9pm on average. The light sensors kick in about 10pm. The light will stay green on rt.320 for 10 minutes or more. Now, if a car came up form the Staples lot, the sensor will trigger and stop traffic on 320, likeit should. But if there is no traffic on either road, and a single car, or two or three approch the light, it will immediately change to yellow.

This is one of about 30 lights on major roads that I've tracked.

[Dedman]

"Slow, Children Playing".

I have seen those signs too. I have always felt that if children want to play in the street, they should be faster.

[AceCombat]

We have sensors here on the lights that, at night, detect light from headlights and change as well as the sensors on the road.

there are even thermal sensors now. Atlanta has a few thermal sensors. and of course EMS/Fire/Police in certain metro areas even have Radio triggers that instantly turn ALL Lights red so a emergency vehicle can pass through quickly and without incident.


i read somewhere on the net, ill have to search for it again....... the optical sensors they are using are sometimes easily triggered by laser pointers. so if you have optical sensors try aiming a laser at the sensor and see if it triggers the light



another thing, when you have a major highway, all the lights at major intersections are linked together by fiber optics networking. notice how the lights with cycle one after another....they know which lights are green, which are cycling and which are red. and they can talk to eachother and keep traffic moving flawlessly, untill some shizwad group of punky drivers comes through and decides he has his/her own set of driving laws. <-- ( very common where i live and its f00king annoying! )

[Kyouryuu]

Traffic lights are pretty sophisticated things. In major metropolitan areas, a lot of them are manually controlled in peak traffic hours by the transportation authority looking through cameras. Generally, however, they are synchronized to provide a stretch or green lights across multiple intersections.

But they can also be rigged to, as was said, alter patterns. My residential neighborhood used to be a way speeders cut through in order to avoid traffic on the main highway. The traffic signals controlling the junction between the road and highway, though, were set up to be very long on the road side. So the time spent speeding through a neighborhood to bypass traffic is wasting at this two-minute red light.

The same lights, though, are intelligent in resetting themselves. For example, if no one has tripped it in a while, they will more quickly turn green than if they were just tripped (i.e. you missed the green light barely).

[roid]

"Slow, Children Playing".

I have seen those signs too. I have always felt that if children want to play in the street, they should be faster.

made me laugh

[Gooberman]

I like the one that says:

"Stop when children are in crosswalk"

I don't even wanna know about the lawsuit that made that sign nessesary.

"Ya I hit the kid, but there was nothing saying I had to stop,"

"He's got us there Cheif"