1116: "Traffic Lights"

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Spectrum
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Re: 1116: "Traffic Lights"

Postby Spectrum » Wed Oct 03, 2012 4:20 pm UTC

Quicksilver wrote:Alt Text:"There's an intersection I drive through sometimes that has a forward green arrow, a red light, and a 'no turns' sign all on one pole. I honestly have no idea what it's telling me to do."


That combination is straightforward: The green arrow means that you can go straight. The red circle means that you can't go, *except* when explicitly overridden by an arrow. Hence you can go straight, but cannot turn (at that moment). In order to inform the drivers that the light will *never* permit them to turn, there is a "NO TURNS" sign.

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Re: 1116: "Traffic Lights"

Postby wumpus » Wed Oct 03, 2012 4:29 pm UTC

Red Hal wrote:Roundabouts are better for traffic flow than four-way stops except under very light traffic conditions. Traffic circles and spiral roundabouts are abominations from the abyss. Oddly enough a mini-roundabout works pretty well as a four-way stop, but with slightly improved characteristics under heavier traffic.


I would agree with you only as far as "light traffic" is defined as half the capacity of a single lane of traffic (at roundabout speed). The catch here is that with a traffic light, you are still cutting capacity down by more than a half (depending on how much time is needed for overlap and left [right for brits] turning cars). Unless four (or more lanes) are actually needed for transit (and not just avoiding turning) the traffic circle is going to win (assuming you have the land for it).

Large roundabouts boggle the mind. I can only assume that the sheer size allows cars to quickly move inside (and be willing to do it) as cars move in and out of the monster. I also assume that drivers are far less transient, and most drivers drive such monsters day in and day out.

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Re: 1116: "Traffic Lights"

Postby rmsgrey » Wed Oct 03, 2012 4:39 pm UTC

darkwombat wrote:
Sounds like you're going to have trouble whether or not there are roundabouts. Evidently, signs and lights are not solving the problem.

You say you want to live. You WILL be more likely to live if some dope doesn't look before pulling into a roundabout in front of you, since you'll be going slower. If the same guy turns right in front of you as you're going 45 through a green light, you won't have nearly as good a chance.

Or take your truck example:
Stop sign at an intersection - hit from behind at 70 MPH, risk of being t-boned by full speed traffic on a straightaway
Yield sign at a roundabout - hit from behind at 70 MPH, risk of being sideswiped by reduced speed traffic in the roundabout


You make a fair point and I'll agree that probably the percentage risk of a fatal accident is less at a roundabout. However I maintain that despite my benadryl guy example, most bad drivers are more likely to successfully navigate a "you have to stop. ok now you can go" stoplight intersection than a "yield to oncoming traffic and get out there when you think it is a good idea" roundabout, and so I feel (rightly or wrongly) at much higher risk when navigating round-abouts. I'm curious what motorcyclists think about them, as even a lower speed accident could be pretty serious for someone not in a steel cage.


I think the big problem y'all'd have is that y'all'd be unfamiliar with roundabouts, so more likely to screw-up while navigating them. Joining a roundabout is no worse than joining a busy road at a T-junction (without traffic lights) - and generally safer since the oncoming traffic will be slower.

They're not ideal for every junction - they take up more space, and in unfavourable traffic conditions, you can be stuck there for a much longer worst-case wait than with lights, so unbalanced traffic flow can cause problems. On the other hand, when they are appropriate, they give better traffic flow and fewer accidents than traffic lights without needing electricity (well, street-lamps...)

So, yeah, dig up a major city's intersections and put in roundabouts. Come back 20 years later and see what the next generation makes of it...

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Re: 1116: "Traffic Lights"

Postby Claveluza » Wed Oct 03, 2012 4:40 pm UTC

At first I was like "cool, I found these annoying too", and then it moved and I was like "WOAAH what's happening?", and then an arrow appeared instead of the green light, and then it turned purple, and I laughed out of sheer incomprehension.

Also, in Argentina we just have a single pole. If you want to turn, wait until light's green. All of you Europeans and North Americans drive me crazy.

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Re: 1116: "Traffic Lights"

Postby PM 2Ring » Wed Oct 03, 2012 4:46 pm UTC

Diadem wrote:Personally, I hate roundabouts. But the traffic planners here in The Netherlands so love them. 20 years ago we hardly had any, but since then they've become in fashion, and now they are all over the place.


They've become quite common in Australia over the last 3 or 4 decades, but it appears that a lot of older drivers (i.e., over 65) are still uncomfortable with them as they tend to approach roundabouts with extreme caution, which can be a bit frustrating for other drivers.

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Re: 1116: "Traffic Lights"

Postby Plutarch » Wed Oct 03, 2012 4:48 pm UTC

Can anyone tell me if the pedestrian buttons at traffic lights actually do anything? When I press the button does it make the traffic lights go red any quicker, stopping the traffic and allowing me to cross the road? And - I'm in Britain - are these pedestrian buttons similarly effective or ineffective everywhere?

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Re: 1116: "Traffic Lights"

Postby Oktalist » Wed Oct 03, 2012 4:55 pm UTC

Plutarch wrote:Can anyone tell me if the pedestrian buttons at traffic lights actually do anything? When I press the button does it make the traffic lights go red any quicker, stopping the traffic and allowing me to cross the road? And - I'm in Britain - are these pedestrian buttons similarly effective or ineffective everywhere?

It may or may not stop the traffic any quicker, but after the traffic has been stopped it should keep it stopped for longer, to give you time to get across.

At traffic lights that exist only as pedestrian crossings (as opposed to intersections), of course the traffic will never be stopped unless the button is pressed.

It is a widely believed fact that you will have to wait longer if you press the button multiple times.
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Re: 1116: "Traffic Lights"

Postby Erzengel » Wed Oct 03, 2012 5:26 pm UTC

darkwombat wrote:My problem with roundabouts is that they require a level of trust in the competency of all other drivers approaching the roundabout which I will never have and which I feel would be entirely unwarranted for anyone to have. I drive with a mindset as if every other driver on the road is a homicidal one-eyed drunken psychopath who is watching TV while driving with their feet. You'd be surprised (or not) how often this outlook has saved me from being involved in an accident.

In 2 decades of driving, I've never been in an accident that was my fault. I've been in quite a few accidents, though, including one that turned my station wagon into a sub-compact and left me with permanent damage to my neck. That one was from somebody who saw my vehicle fully stopped in front of him at a stop sign, in broad daylight, and never touched the brakes on his 70+MPH truck because he was zoned out on benadryl.

People like this exist. I simply cannot trust that they understand how to navigate a round-about. They NEED signs and lights. Really. Fuck traffic flow. I want to live.

(edited for typos)

Where I work (San Diego, CA, USA. Cars on the right, roundabouts are rare) there is a roundabout at the entrance to the private parking areas. There's one parking area to the left for the apartment complex over there. To the right is the front of my office building. Straight across from the entrance is the back parking lot, where I park. As I exit from the back, go right around the roundabout to the exit, I have twice had to stop hard and honk REALLY ANGRILY at a moron who went left around the roundabout to get to the apartment parking lot.
Sure, roundabouts may be a slower speed, but if someone doesn't know how to navigate them, you end up in a head-on collision.

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Re: 1116: "Traffic Lights"

Postby Von_Cheam » Wed Oct 03, 2012 5:37 pm UTC

As a motorcyclist, cyclist and a cager, in Britain, I feel far safer with light-controlled junctions no matter how I'm travelling - but if I'm in a hurry I seem prefer to encounter roundabouts on slower/minor road junctions and lights at faster/main road junctions, regardless of traffic volumes.

Of course, this is subjective and I probably don't estimate waiting/queuing times very well when I'm in a hurry. This being said, if I'm riding a motorcycle or bicycle I hardly ever queue and I make use of the waiting times to filter to the front - but in these instances I still seem to prefer minor road roundabouts and main road light-controlled junctions.

I know many junctions where the pedestrian "green man" always follows the pattern of being perpendicular to the vehicular green light and pressing the button does nothing to alter the pattern - I also know others where pressing the button introduces an extra "step" (phase?) into the sequence.

Von Cheam

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Re: 1116: "Traffic Lights"

Postby Oktalist » Wed Oct 03, 2012 5:42 pm UTC

I'm a fan of these two UK road signs, with two quite different meanings:

Image
One Way
This road has only one legal direction of flow; traffic is forbidden to travel in the opposite direction. It should be understood, therefore, than a U-turn may not be performed, as this would place you against the legal flow of traffic. Turns to the left or right are allowed unless otherwise stated.

Image
Ahead Only
No left turns. No right turns. No U-turns. Traffic may flow in both directions.
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Re: 1116: "Traffic Lights"

Postby ike » Wed Oct 03, 2012 5:59 pm UTC

dp2 wrote:
AvatarIII wrote:
dp2 wrote:
mochafairy wrote:This reminds me of the lights we have around here for Michigan lefts, which is a seriously messed up traffic design. Just put in a roundabout/traffic circle. And then all the stop light problems are fixed!

NO!

I have no problem with roundabouts where appropriate. But Michigan lefts are usually used for turning left on to a 45+ MPH road or highway with three or more lanes each way. Not appropriate for roundabouts.

I'm not sure what you mean about the traffic lights. It's usually a just regular light with no left turn.


I will agree that this is true, however, only for a single level interchange. If you add a second level, using round-abouts does make sense
The most common type of interchange in the UK and Ireland is the dumbbell interchange, and it works, which is why it's pretty much ubiquitous.
Image

Yeah, we don't have those. I think they could be put to good use in Michigan, where there may be six to eight ramps on and off I-75 to a major road.

Edit: oh, actually, we do.



Geddies and 23 in A2



darkwombat wrote:My problem with roundabouts is that they require a level of trust in the competency of all other drivers approaching the roundabout which I will never have and which I feel would be entirely unwarranted for anyone to have. I drive with a mindset as if every other driver on the road is a homicidal one-eyed drunken psychopath who is watching TV while driving with their feet. You'd be surprised (or not) how often this outlook has saved me from being involved in an accident.

In 2 decades of driving, I've never been in an accident that was my fault. I've been in quite a few accidents, though, including one that turned my station wagon into a sub-compact and left me with permanent damage to my neck. That one was from somebody who saw my vehicle fully stopped in front of him at a stop sign, in broad daylight, and never touched the brakes on his 70+MPH truck because he was zoned out on benadryl.

People like this exist. I simply cannot trust that they understand how to navigate a round-about. They NEED signs and lights. Really. Fuck traffic flow. I want to live.

(edited for typos)



either their needs to be stiffer legal penalties or the first person to arrive at the accident just needs to shoot the wreck-less driver.

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Re: 1116: "Traffic Lights"

Postby Erzengel » Wed Oct 03, 2012 6:03 pm UTC

ike wrote:either their needs to be stiffer legal penalties or the first person to arrive at the accident just needs to shoot the wreck-less driver.

Or Google needs to hurry up with those cars of theirs.

Also, shouldn't it be the wreckful driver? (Or the reckless one)

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Re: 1116: "Traffic Lights"

Postby myoilu » Wed Oct 03, 2012 6:07 pm UTC

for the impatient, i sped it up.

Image

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Re: 1116: "Traffic Lights"

Postby freezeblade » Wed Oct 03, 2012 6:12 pm UTC

Erzengel wrote:Or Google needs to hurry up with those cars of theirs.


They just signed a law here (California) that they could test 'em on public roads. livin the dream soon.
http://www.bgr.com/2012/09/26/google-driverless-car-california/
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Re: 1116: "Traffic Lights"

Postby JJH » Wed Oct 03, 2012 6:23 pm UTC

Highway engineer prank #62? Actually this one made me shiver at first, it looks horribly dangerous. If I ever had to go trough this I'd do my best to pick the second lane from the right. It only does two weird things and seems to be mostly green.

Also I don't get all the hate for roundabouts, they work (but people often do not).

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Re: 1116: "Traffic Lights"

Postby suso » Wed Oct 03, 2012 6:35 pm UTC

da Doctah wrote:The newest thing they're testing here in Phoenix is flashing yellow left-turn arrows. That wasn't covered when I got my license, so I'm going to have to interpret it as a transmission from the mothership.

Red light: stop.
Green light: go.
Yellow light: go, very fast.
Flashing blue light: you're driving through a K-Mart.


Nice Starman ref.
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Re: 1116: "Traffic Lights"

Postby mathmannix » Wed Oct 03, 2012 7:27 pm UTC

da Doctah wrote:Red light: stop.
Green light: go.
Yellow light: go, very fast.


Green light: go.
Yellow light: go faster.
Red light: go faster, while honking.
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Re: 1116: "Traffic Lights"

Postby bmonk » Wed Oct 03, 2012 7:32 pm UTC

derjsot wrote:
Himself wrote:According to David Letterman, the purple light means "up to you."

Isn't that the yellow light?

No. Depending on the locale, yellow means either "Speed much faster" or "Only ten more cars".
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Re: 1116: "Traffic Lights"

Postby drazen » Wed Oct 03, 2012 7:40 pm UTC

There's an intersection I drive through sometimes that has a forward green arrow, a red light, and a 'no turns' sign all on one pole. I honestly have no idea what it's telling me to do.


I strongly suspect that Randall is talking about being on Mass Ave near Central Square, Cambridge, MA. There are a lot of straight arrows with no-left-turn signs in that area (which doesn't help getting in and out of there, given how few roads actually go directly to/from that general area all the way from the city limits), as well as several intersections where you are told "Left turn on green arrow only."

The other place I've seen something like this in the area is on Route 16 in Revere, where I think it's straight green arrows with a solid red light (instead of a left red arrow) when left-turns are forbidden. If there's a "No Turns" sign anywhere along there, maybe it's for a one-way street merging into 16 (probably 99).
Last edited by drazen on Thu Oct 04, 2012 2:21 am UTC, edited 1 time in total.

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Re: 1116: "Traffic Lights"

Postby cream wobbly » Wed Oct 03, 2012 7:55 pm UTC

AvatarIII wrote:who needs traffic lights when you can have round-abouts....

round-abouts that have traffic lights on them part way round :| ....

also I just noticed the bird moves :)

You could have roundabouts-from-hell with traffic lights on them as well. That would be fun.

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Re: 1116: "Traffic Lights"

Postby Pfhorrest » Wed Oct 03, 2012 8:00 pm UTC

I'm a big fan of roundabounds because they simplify all traffic flow rules to those of the highway: yield to traffic from your [side of the road you don't drive on], and try to stay out of the [side you drive on]-most lane unless entering or exiting the road. Highways treat traffic like the fluid it is best modeled as, and roads as pipes. There are no valves, and we don't expect the molecules of the fluid (cars) to do anything but keep traveling in the direction they were headed and stay as spaced out as volume (road capacity) and temperature (traffic speed) dictates, and it's just up to the civil engineers to make sure we don't shoot two streams of traffic-fluid directly at or across each other but instead flow them together fluidly. (Let the Ghostbusters design the roads from now on... they know better than to cross the streams). No stops, no intersections proper; roads just merge and split from each other. A roundabound is just a small section of road facilitating the merging and splitting of two larger flows of traffic: you merge into the circle just like you would merge from one highway onto another (yielding to traffic already traveling in it), and then you merge out of the circle just like you would split off of one highway onto another.

The roundabouts just need to be designed such that it's obvious that you are merging with another road, and not intersecting with it; that you can't turn back up that road in the wrong direction (nobody thinks that they can, from a right-lane highway onramp, turn left down the highway against traffic), and that you have to yield to traffic already in that road. For existing roundabouts, pervasive "right turn only, yield to left" signs (presuming a right-side-of-the-road country, flip directions if otherwise) would solve the problem of idiots not knowing what to make of them.

Also, don't do this. Seriously, just... no. Don't.
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Re: 1116: "Traffic Lights"

Postby cream wobbly » Wed Oct 03, 2012 8:06 pm UTC

Oktalist wrote:I'm a fan of these two UK road signs, with two quite different meanings:

Image
One Way
This road has only one legal direction of flow; traffic is forbidden to travel in the opposite direction. It should be understood, therefore, than a U-turn may not be performed, as this would place you against the legal flow of traffic. Turns to the left or right are allowed unless otherwise stated.

Image
Ahead Only
No left turns. No right turns. No U-turns. Traffic may flow in both directions.

I don't see a problem. See, context is your friend.

A rectangular board is for information. Circular is mandatory.

It is not mandatory to head down a one-way street, so a rectangular board is used. It is mandatory not to head down the other end of the one-way street, which is where you'll find a circular No Entry sign. Similarly, it is mandatory to travel Ahead Only when you see the circular board above.

Stop complaining. Here in the US, we have to put up with signs written on the road in reverse speak, for example:

AHEAD
STOP


Which leaves me 30 meters down the street thinking "is that a bit like a head start?".

Many signs are verbose here instead of there being a Federal standard. Personally, I think the signwriting companies here are the same lot who print football shirts -- must get paid by the letter.

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Re: 1116: "Traffic Lights"

Postby cream wobbly » Wed Oct 03, 2012 8:18 pm UTC

Pfhorrest wrote:[blah]

The roundabouts just need to be designed such that it's obvious that you are merging with another road, and not intersecting with it; that you can't turn back up that road in the wrong direction (nobody thinks that they can, from a right-lane highway onramp, turn left down the highway against traffic), and that you have to yield to traffic already in that road. For existing roundabouts, pervasive "right turn only, yield to left" signs (presuming a right-side-of-the-road country, flip directions if otherwise) would solve the problem of idiots not knowing what to make of them.

When roundabouts were introduced in France and Holland (I don't know about earlier implementations in other countries), the rule was "yield to traffic entering the roundabout". I'm not sure when this changed, but it did in response to Britain's implementation with "yield before entering".

This difference probably was probably due to the (still prevalent) difference in philosophy on urban roads, where oncoming traffic has priority: traffic on the main road yields (where reasonable) to oncoming traffic. In the UK, it's as in the US: once you're in, urine.

Pfhorrest wrote:Also, don't do this. Seriously, just... no. Don't.


Once you see a roundabout as a circular one-way street, it suddenly makes a lot more sense.

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Re: 1116: "Traffic Lights"

Postby Fire Brns » Wed Oct 03, 2012 8:47 pm UTC

I remember reading forever ago on my old computer that removing traffic lights made intersections safer. I'll try and find source. Something about people not liking being herded like sheep.

There are three schools a stone's throw away from my house, not kidding, I threw a rock and it landed on the sidewalk to the elementary school.
Anyway there are two roads to get to it and both lead out to the same highway; one is a long winding road through a subdivision with a traffic light intersection and the other one was a straight low traffic road with no intersection lights.
"Was" being the important road, they put in lights at that intersection so that buses could legally take it and not clog up traffic in the subdivision.
That plan ended up making it the most frustrating intersection in a 15 square mile area. Traffic backs up like newspaper in a public toilet and 2 minor accidents have happened since they put the light in.
They didn't have the sense to just make the intersection all flashing yellow during times when buses shouldn't be passing through it.
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Re: 1116: "Traffic Lights"

Postby bmonk » Wed Oct 03, 2012 9:06 pm UTC

Plutarch wrote:Can anyone tell me if the pedestrian buttons at traffic lights actually do anything? When I press the button does it make the traffic lights go red any quicker, stopping the traffic and allowing me to cross the road? And - I'm in Britain - are these pedestrian buttons similarly effective or ineffective everywhere?

I believe that usually the pedestrian signals are not going--but when you push the button, it warns the system to use them, and possibly to lengthen the time so that you can cross safely.
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Re: 1116: "Traffic Lights"

Postby aega » Wed Oct 03, 2012 9:40 pm UTC


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Re: 1116: "Traffic Lights"

Postby keithl » Wed Oct 03, 2012 9:51 pm UTC

The signage is insufficient. Drivers need to know the point score for pedestrians:
Image

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Kaden
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Re: 1116: "Traffic Lights"

Postby Kaden » Wed Oct 03, 2012 10:03 pm UTC

On my written driver's test (in Wisconsin at the time), one of the questions asked what to do if you got to an intersection and the light was flashing red. One of the possible answers was "wait until it stops." :roll:

EDIT: Typo.
Image

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Re: 1116: "Traffic Lights"

Postby *** » Wed Oct 03, 2012 10:14 pm UTC

dp2 wrote:
darkwombat wrote:My problem with roundabouts is that they require a level of trust in the competency of all other drivers approaching the roundabout which I will never have and which I feel would be entirely unwarranted for anyone to have. I drive with a mindset as if every other driver on the road is a homocidal one-eyed drunken psychopath who is watching TV while driving with their feet. You'd be surprised (or not) how often this outlook has saved me from being involved in an accident.

In 3 decades of driving, I've never been in an accident that was my fault. I've been in quite a few accidents, though, including one that turned my station wagon into a sub-compact and left me with permanent damage to my neck. That one was from somebody who saw my vehicle fully stopped in front of him at a stop sign, in broad daylight, and never touched the brakes on his 70+MPH truck because he was zoned out on benadryl.

People like this exist. I simply cannot trust that they understand how to navigate a round-about. They NEED signs and lights. Really. Fuck traffic flow. I want to live.

Sounds like you're going to have trouble whether or not there are roundabouts. Evidently, signs and lights are not solving the problem.

You say you want to live. You WILL be more likely to live if some dope doesn't look before pulling into a roundabout in front of you, since you'll be going slower. If the same guy turns right in front of you as you're going 45 through a green light, you won't have nearly as good a chance.

Or take your truck example
Stop sign at an intersection - hit from behind at 70 MPH, risk of being t-boned by full speed traffic on a straightaway
Yield sign at a roundabout - hit from behind at 70 MPH, risk of being sideswiped by reduced speed traffic in the roundabout

Wouldnt the guy going 70 be t-ing up 1 or two people when HE enters the roundabout?
I think a guy going into ANY intersection doing 70 is a bit of a problem. He could kill anyone anywhere.
And people dont go that much slower in rotaries. In places like Boston, its more about edging people out than worrying about getting hit (although most of the time we manage both).

On another note, you know those narrow 2-lane roads where the speed limit is about 50mph and everyone goes 60? You ever think about how close you are to the opposite lane? Its like 3 feet! A 120mph crash is 3 feet away from you! Youre 3ft from death! And when youre a pedestrian, thats like a foot and a half!
We all thought about it when we first learned to drive, but have you ever gone back to that way of thought?
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Re: 1116: "Traffic Lights"

Postby brenok » Wed Oct 03, 2012 11:50 pm UTC

Djehutynakht wrote:No fear, the same engineer who designed http://xkcd.com/277/ designed this too.


It all works out.

He programmed the lights so that they would align perfectly during every Transit of Venus. You can go then.


No, I think that was this engineer: http://xkcd.com/253/

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Re: 1116: "Traffic Lights"

Postby Woad-Warrior » Thu Oct 04, 2012 12:38 am UTC

mochafairy wrote:This reminds me of the lights we have around here for Michigan lefts, which is a seriously messed up traffic design. Just put in a roundabout/traffic circle. And then all the stop light problems are fixed!


Unless you're in Arkansas ;)

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Re: 1116: "Traffic Lights"

Postby CatCube » Thu Oct 04, 2012 1:11 am UTC

Plutarch wrote:Can anyone tell me if the pedestrian buttons at traffic lights actually do anything? When I press the button does it make the traffic lights go red any quicker, stopping the traffic and allowing me to cross the road? And - I'm in Britain - are these pedestrian buttons similarly effective or ineffective everywhere?


Signals can operate in several general ways: timed, semi-actuated, or fully actuated.

Timed signals simply run from one phase to the next in a fixed sequence controlled by a simple timer. Depending on circumstances, they can produce much longer delays. OTOH, you cannot run something like the "green wave" of signals (where if you drive the speed limit through one green light, all the lights you hit will be green) unless you have fixed times.

Actuated signals use an induction loop in the road to control when phases change. Semi-actuated signals are when one major street will have a green until a vehicle pulls up over the actuator on a side street. This leaves traffic free to go on the main drag, but allows side streets to turn or cross with a light. Fully actuated signals have induction loops controlling from both directions.

What does this have to do with your question? At actuated intersections, people won't trip the induction loop. If no car arrives going in the same direction you want to walk, you'll wait at that corner all damn day. Pushing the button generates a demand to the signal controller. As people have mentioned, sometimes intersections won't have a phase long enough for a pedestrian to cross, and won't display the "Walk" signal until you press the button because it won't bother making the phase you can cross long enough if there's no pedestrian waiting, because it increases intersection delay. Intersection delay translates to wasted gas.

Fire Brns wrote:I remember reading forever ago on my old computer that removing traffic lights made intersections safer. I'll try and find source. Something about people not liking being herded like sheep.


Traffic signals often increase the accident rate at intersections. However, they change the types of accidents. Rear-end collisions increase dramatically when lights are installed, but you reduce T-bones from turning or crossing traffic, which are much more dangerous. Depending on the traffic volume, it may not make sense to signalize an intersection. You have to balance the risks of rear-end and T-bone collisions and make a decision.


cream wobbly wrote:Many signs are verbose here instead of there being a Federal standard. Personally, I think the signwriting companies here are the same lot who print football shirts -- must get paid by the letter.


There is a federal standard--the Manual on Uniform Traffic Control Devices, found here: http://mutcd.fhwa.dot.gov/ There is a provision for states to extend from it a bit, but they're trying to rein everybody in. The problem is that we had very widely-separated zones of traffic for many years, and their own traditions grew up in each. It's both expensive for the state and frustrating for drivers to change, especially if the differences are essentially arbitrary. It's easier to have everybody on one standard, but when there's no clear reason to prefer one over the rest, other than "that's how we did it where I grew up, dammit," it can get contentious. California used to number exits sequentially, while the east coast used mile markers. When there were few drivers crossing the country, it didn't matter so much. Now, however...

Also, there's been a push to reduce written signs for many years. However, it's difficult to draft pictorial signs with obvious meaning (Seriously, what does the biohazard or radiation symbols have to do with their respective subjects? You just have to know what they mean.) If you introduce an arbitrary symbol, you then have to get everybody to learn what it means, and it's not politically possible to make all drivers read new rules and take a test every year.

My traffic professor had us do an assignment once: Create a sign to warn drivers of Canada geese crossing the road. A week or so later, we had a vast variety of permutations turned in and posted up in the front of the class. He went to the first one, and asked "How can I tell that this is a Canada goose?" (It didn't have the characteristic white band around the throat.) He went to the next one, with a well-drawn silouhette of a Canada goose standing, white throat and all. He asked, "Does this mean that driver's have to watch for just standing geese? What about crossing geese?" The one with a flying Canada goose silhouette, he asked if about ones standing or walking across the road. The sign saying "Canada goose x-ing" he picked at whether people would understand the "x-ing=crossing". And for the sign "Canada goose crossing"--"What if they can't read?"

Seriously, sign design is fucking hard.

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Re: 1116: "Traffic Lights"

Postby J Thomas » Thu Oct 04, 2012 2:01 am UTC

*** wrote:
On another note, you know those narrow 2-lane roads where the speed limit is about 50mph and everyone goes 60? You ever think about how close you are to the opposite lane? Its like 3 feet! A 120mph crash is 3 feet away from you! Youre 3ft from death! And when youre a pedestrian, thats like a foot and a half!
We all thought about it when we first learned to drive, but have you ever gone back to that way of thought?


Yes! It's scary! But you can't go through life being scared all the time.

So I try to drive defensively, and I think about what to do if people 6 cars ahead of me make a mistake. I try to stay 4 seconds behind whoever's in front of me, and if the guy behind me gets too close I slow down.

People get frustrated with me when I drive, because I keep letting other drivers intimidate me into letting them get one carlength ahead while I get one carlength behind. They want me to be braver and show everybody I meet that they can't get away with anything.

I figure on an average trip it might cost me 5 to 10 carlengths. Every now and then I get stopped at a stoplight that I would have gotten through if I had been more aggressive and been a few carlengths earlier.

It bothered me when I was dating. Girls would think I was timid when I drove carefully. "You let a Volkswagen intimidate you?" "I just didn't want to have an accident." The reward isn't just to get one carlength ahead. It's also potentially the admiration of a beautiful woman.
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Re: 1116: "Traffic Lights"

Postby Pfhorrest » Thu Oct 04, 2012 2:14 am UTC

cream wobbly wrote:
Pfhorrest wrote:Also, don't do this. Seriously, just... no. Don't.


Once you see a roundabout as a circular one-way street, it suddenly makes a lot more sense.

Yeah, that was pretty much my point in the first paragraph. But mister swirly here is an unnecessarily complicated mess of one circular one way streets requiring way more entrances and exits than necessary.
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Re: 1116: "Traffic Lights"

Postby CatCube » Thu Oct 04, 2012 2:30 am UTC

J Thomas wrote:
*** wrote:
On another note, you know those narrow 2-lane roads where the speed limit is about 50mph and everyone goes 60? You ever think about how close you are to the opposite lane? Its like 3 feet! A 120mph crash is 3 feet away from you! Youre 3ft from death! And when youre a pedestrian, thats like a foot and a half!
We all thought about it when we first learned to drive, but have you ever gone back to that way of thought?


Yes! It's scary! But you can't go through life being scared all the time.

So I try to drive defensively, and I think about what to do if people 6 cars ahead of me make a mistake. I try to stay 4 seconds behind whoever's in front of me, and if the guy behind me gets too close I slow down.

People get frustrated with me when I drive, because I keep letting other drivers intimidate me into letting them get one carlength ahead while I get one carlength behind. They want me to be braver and show everybody I meet that they can't get away with anything.

I figure on an average trip it might cost me 5 to 10 carlengths. Every now and then I get stopped at a stoplight that I would have gotten through if I had been more aggressive and been a few carlengths earlier.

It bothered me when I was dating. Girls would think I was timid when I drove carefully. "You let a Volkswagen intimidate you?" "I just didn't want to have an accident." The reward isn't just to get one carlength ahead. It's also potentially the admiration of a beautiful woman.


This is something that I wish more people realized. I watch somebody swerving across lanes to find a hole in crowded traffic, and otherwise being an unpredictable nuisance. When they're on the road with me a while, I keep track of the position of their car. After 15-20 minutes, it's usually like 15 seconds ahead of me. I've gotten off at the same exit as some of these people and caught up to them at the signal on the cross street. Driving like an asshole doesn't actually save very much time.

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Re: 1116: "Traffic Lights"

Postby dp2 » Thu Oct 04, 2012 3:10 am UTC

*** wrote:
dp2 wrote:
darkwombat wrote:My problem with roundabouts is that they require a level of trust in the competency of all other drivers approaching the roundabout which I will never have and which I feel would be entirely unwarranted for anyone to have. I drive with a mindset as if every other driver on the road is a homocidal one-eyed drunken psychopath who is watching TV while driving with their feet. You'd be surprised (or not) how often this outlook has saved me from being involved in an accident.

In 3 decades of driving, I've never been in an accident that was my fault. I've been in quite a few accidents, though, including one that turned my station wagon into a sub-compact and left me with permanent damage to my neck. That one was from somebody who saw my vehicle fully stopped in front of him at a stop sign, in broad daylight, and never touched the brakes on his 70+MPH truck because he was zoned out on benadryl.

People like this exist. I simply cannot trust that they understand how to navigate a round-about. They NEED signs and lights. Really. Fuck traffic flow. I want to live.

Sounds like you're going to have trouble whether or not there are roundabouts. Evidently, signs and lights are not solving the problem.

You say you want to live. You WILL be more likely to live if some dope doesn't look before pulling into a roundabout in front of you, since you'll be going slower. If the same guy turns right in front of you as you're going 45 through a green light, you won't have nearly as good a chance.

Or take your truck example
Stop sign at an intersection - hit from behind at 70 MPH, risk of being t-boned by full speed traffic on a straightaway
Yield sign at a roundabout - hit from behind at 70 MPH, risk of being sideswiped by reduced speed traffic in the roundabout

Wouldnt the guy going 70 be t-ing up 1 or two people when HE enters the roundabout?
I think a guy going into ANY intersection doing 70 is a bit of a problem. He could kill anyone anywhere.

Indeed he could. But he is made no more dangerous by a roundabout, and in most cases less so.

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Re: 1116: "Traffic Lights"

Postby ve_ » Thu Oct 04, 2012 5:17 am UTC

this is clearly a scheme to kill bikers..

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Re: 1116: "Traffic Lights"

Postby ve_ » Thu Oct 04, 2012 5:20 am UTC

dp2 wrote:
*** wrote:
dp2 wrote:
darkwombat wrote:My problem with roundabouts is that they require a level of trust in the competency of all other drivers approaching the roundabout which I will never have and which I feel would be entirely unwarranted for anyone to have. I drive with a mindset as if every other driver on the road is a homocidal one-eyed drunken psychopath who is watching TV while driving with their feet. You'd be surprised (or not) how often this outlook has saved me from being involved in an accident.

In 3 decades of driving, I've never been in an accident that was my fault. I've been in quite a few accidents, though, including one that turned my station wagon into a sub-compact and left me with permanent damage to my neck. That one was from somebody who saw my vehicle fully stopped in front of him at a stop sign, in broad daylight, and never touched the brakes on his 70+MPH truck because he was zoned out on benadryl.

People like this exist. I simply cannot trust that they understand how to navigate a round-about. They NEED signs and lights. Really. Fuck traffic flow. I want to live.

Sounds like you're going to have trouble whether or not there are roundabouts. Evidently, signs and lights are not solving the problem.

You say you want to live. You WILL be more likely to live if some dope doesn't look before pulling into a roundabout in front of you, since you'll be going slower. If the same guy turns right in front of you as you're going 45 through a green light, you won't have nearly as good a chance.

Or take your truck example
Stop sign at an intersection - hit from behind at 70 MPH, risk of being t-boned by full speed traffic on a straightaway
Yield sign at a roundabout - hit from behind at 70 MPH, risk of being sideswiped by reduced speed traffic in the roundabout

Wouldnt the guy going 70 be t-ing up 1 or two people when HE enters the roundabout?
I think a guy going into ANY intersection doing 70 is a bit of a problem. He could kill anyone anywhere.

Indeed he could. But he is made no more dangerous by a roundabout, and in most cases less so.


a roundabout with a concrete center might slow him down a bit :)

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Re: 1116: "Traffic Lights"

Postby Max™ » Thu Oct 04, 2012 5:56 am UTC

keithl wrote:The signage is insufficient. Drivers need to know the point score for pedestrians:
Image

Only ten points? Barely worth scuffing the paint.

Ok, I'm over in the states so I'm unsure of the proper way to handle a roundabout... this is right, yes?
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Re: 1116: "Traffic Lights"

Postby cptjeff » Thu Oct 04, 2012 7:08 am UTC

Suralin wrote:I'm not sure how roundabouts could possibly be better than intersections. I despise the roundabouts here in DC and I swear it doesn't help traffic much at all, especially with bad drivers.


Google decided to route me through Washington Circle at rush hour recently, I think they thought it would be a funny little joke (in a slightly less sinister version of this). It was not funny.

Seriously, in DC, the roundabouts are at 8 way intersections, with some frontage roads thrown in on top, just to add to the confusion. Anytime I'm near one while in a car one I feel like digging Pierre L'Enfant up and desecrating the body in some way.


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