How aggravating are stoplights? Would you be even more aggravated to know that they only add to congestion? The two videos I have posted below are very interesting and very infuriating if you accept the claims.

http://www.foxbusiness.com/on-air/stossel/index.html#/v/4304480/do-we-really-need-traffic-lights/?playlist_id=87050

http://www.youtube.com/watch?v=vi0meiActlU

^^ Why do you think the massive roundabouts in Europe don't have any kind of painted lanes or what so ever?
But there is something that tells me this wouldn't work in the states....

^^ Why do you think the massive roundabouts in Europe don't have any kind of painted lanes or what so ever?

I don't see what you're getting at.

But there is something that tells me this wouldn't work in the states....

It's at least worth a try. Stoplights are expensive.

I don't see what you're getting at.



It's at least worth a try. Stoplights are expensive.


At first the massive roundabouts had several lanes painted on them and traffic grinded to a hold. Now the traffic just moves trough each other but flued.

It's quite funny how these Amercians filming can't believe there eyes :D

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I think American people are to used to all the signs and traffic lights. In europe small streets of the city centers traffic lights are rare, people already got used to it. But it's worth a try indeed!

Cool videos. Great example of how traffic flows well without any strict controls.

^^ This doesn't work everywhere, particularly when roads are very well trafficked and close to capacity.

British signal controlled roundabouts move like machines, much more efficient than Parisien ones with priorite a droite.

^^ This doesn't work everywhere, particularly when roads are very well trafficked and close to capacity.

That's the Champs Elysee in the vid, it's full capacity all the time...

Roundabouts work in the US. The city of Carmel, IN has over 60 of them and Greenwood, IN is starting to implement them as well.

I sincerely doubt overall movement is "faster" in that Paris roundabout. There are a lot of cars just waiting for a chance to dart through. I'll bet more order to the system would speed things up.
It has been my experience that roundabouts with smaller amounts of traffic work well, but heavily travelled intersections work better with traffic lights.

^^
Anyway The massive roundabout of l'Etoile in Paris has traffic lights before in (and there is even a road tunnel to bypass it in direction Champs-Élysées / Grande Armée)

Simply it has to many roads converging (12 roads, half of 'em main roads with 3/6 lanes each direction) and there is too many traffic to work well; pratically impossible to manage

The problem is that Etoile was built in the end of XIX century when car traffic didn't exist and the only parameter used was the 'monumentality'
Unforunately with mass motorization this 'roundabout' became a complete disaster for the traffic (but we can say the same thing for pratically everything built in Europe before the car was invented)

http://www.roumanie-france.ro/images/photos/franta/paris%20-%20place%20de%20l%27etoile.jpg

Anyway modern roundabouts take in account the traffic parameters and they're designed to work well, and it's rare to find that mess you can see in the videos.
That said, roundabouts are not the solution for everything: in NA cities, for istance, the problem is not directely related to the high number of traffic lights, but to the high number of intersections (that obviously have often a traffic light) due to the 'size' of the blocks, generally smaller than the ones you can find in European cities and to their grid shape with few broadways. Those two elements make the car traffic run slow (independently by the congestion); probably roundabouts in some points can help, but at every intersection will be like a funfair carousel

^^ well said. +1

Roundabouts work in the US. The city of Carmel, IN has over 60 of them and Greenwood, IN is starting to implement them as well.

We might as well try it because stoplights are working pretty horribly here. It seems like we'd have less queuing, less stop and go traffic, which is a real killer on fuel consumption, not to mention the high cost of maintaining those stoplights as well.

^^ well said. +1

I think it would work better, for American cities, to close the access of 'secondarian' roads to the main roads, to diminish drastically the number of the intersections having 500/600 m at least between two intersections. To enter the secondarian roads you have to 'interchange' with a 'district' road which has all the intersections 'opened'

Partially this system is in use in some NA cities, but probably a more radical extension is needed

I sincerely doubt overall movement is "faster" in that Paris roundabout. There are a lot of cars just waiting for a chance to dart through. I'll bet more order to the system would speed things up.Stoplights need 2 things to work :
- Reserve areas where cars can stop without blocking other traffics.
- Frequent enough green lights to empty those reserve areas.

The issue with Place de l'Etoile is that it has none of both. There are 12 avenues joining in that circus, which means too much waiting time for each avenue to get the green light one after the other. 12 avenues also means that you can't engage cars in the roundabout using stoplights because of a lack of room. This has already been experienced in the past and it has lead to total gridlock.

Place de l'Etoile is a unique case in Paris. In other very large squares and circus, there are stoplights because the two conditions told above can be met. That's why I wouldn't make a rule out of it as Phattonez is implying. I don't know many other circus with such a small radius where 12 avenues join.

I must add by the way that Place de l'Etoile is a very fluid area. It doesn't generate trafic jam at all. And it's known to be a place with very few accidents. Looked from above, it seems totally unorganized, but once you drive through, it's quite easy to be honnest. It's just a roundabout. And roundabouts doesn't need stoplights to work.

It seems Genius Loci has been faster than me !

^^ Why do you think the massive roundabouts in Europe don't have any kind of painted lanes or what so ever?
But there is something that tells me this wouldn't work in the states....

You could try this lovely one from Swindon

http://2.bp.blogspot.com/_DrvImR2-8Eg/TPkixynZ7KI/AAAAAAAAAJ8/VpmveZafz88/s640/3.JPG

roundabouts take up more land than a normal 4 way stoplights. I also hate driving around those curves and having to slow down when you are driving when there is no traffic. during non-rush hours stoplights are fasters since you don't have to slow down at every damn intersection. Especially on main roads when the stoplights are timed that you hit all green lights between major intersections.

^^ Why do you think the massive roundabouts in Europe don't have any kind of painted lanes or what so ever?
But there is something that tells me this wouldn't work in the states....Well, I don't want to make rules of anything but I believe there are only 2 principles to know as a driver in order to reduce congestion.

1st principle : the less time you spend in a spot, the better it is.
2nd principle : don't block other traffics.

Both principle can seem contradictory as the first one can incite you to not respect painted lanes whereas the other one incite you to do so. Afterwards, it's all about anyone's own critical thinking to determine what's the best solution considering the situation.

I had a friend who told me that once he arrived in Paris, he couldn't understand why people always form new lanes in the streets of Paris when they aren't painted on ground. After driving there for a while, he started to do the same, because it was indeed reducing congestion, allowing more cars to drive through during green lights.

However, when you drive this way, there's always a silly guy engaging in an intersection when the traffic above blocks him. And this generally leads to a jam. So as you can see, it's not a perfect rule.

Anyway, in the US, there is generally a lot of room, so just following the lanes and taking no personnal initiative works fairly well.

roundabouts take up more land than a normal 4 way stoplights. I also hate driving around those curves and having to slow down when you are driving when there is no traffic. during non-rush hours stoplights are fasters since you don't have to slow down at every damn intersection. Especially on main roads when the stoplights are timed that you hit all green lights between major intersections.

Bolded in order to point out that this is only for non-rush hour. During rush hour there is no contest between roundabouts and stoplights. They just handle the traffic better.

roundabouts take up more land than a normal 4 way stoplights. I also hate driving around those curves and having to slow down when you are driving when there is no traffic. during non-rush hours stoplights are fasters since you don't have to slow down at every damn intersection. Especially on main roads when the stoplights are timed that you hit all green lights between major intersections.I agree with you, but this only work in a grid street-layout. That's all you have in the US so it's fine the way it is. And your cities are very wide so there aren't too many people in a same spot.

However here in Europe, we have many squares with more than 4 ways. And it's only then that you need to think of a better solution to keep traffic fluid.

The extra queue space that you need because of stoplights also takes up land. That land isn't necessary with roundabouts.

You could try this lovely one from Swindon

http://2.bp.blogspot.com/_DrvImR2-8Eg/TPkixynZ7KI/AAAAAAAAAJ8/VpmveZafz88/s640/3.JPG

I think this one has been posted in every single thread talkin' of roundabouts

What's scary about Place de l'Etoile is most of the 12 roads seem to be main roads / thoroughfares.

Given the width of Champs-Elysee, is it not possible for a 2x2 underpass to be built a la Hyde Park Corner? On Google Earth it looks like there is a small underpass for E-W traffic, but there isn't anything for the other direction. With the ramaining traffic, what you could do is this:

'Make' Champs-Elysee/Grande-Armee and Wagram/Kleber the 'main' roads of the intersection and install lights at their entrances and exits, so what you now create is a standard signal-controlled roundabout intersection of 2 roads, and on the roundabout traffic will be going in 'batches'. Other entrances would simply have to give way to the roundabout, and gaps between batches would allow traffic from the secondary non-signalled entrances in. If traffic is directed in such a way that the smaller entrances are not heavily used, the gaps would be sufficient to absorb traffic from secondary entrances. If possible, some entrances might even be blocked off like Hoche and Carnot.

What's scary about Place de l'Etoile is most of the 12 roads seem to be main roads / thoroughfares.

Given the width of Champs-Elysee, is it not possible for a 2x2 underpass to be built a la Hyde Park Corner? On Google Earth it looks like there is a small underpass for E-W traffic, but there isn't anything for the other direction.It's not possible to make an underpass in the West-East direction because of the metro which is just below (4 independent lines : M1, M2, M6 and RER A).

With the ramaining traffic, what you could do is this:

'Make' Champs-Elysee/Grande-Armee and Wagram/Kleber the 'main' roads of the intersection and install lights at their entrances and exits, so what you now create is a standard signal-controlled roundabout intersection of 2 roads, and on the roundabout traffic will be going in 'batches'. Other entrances would simply have to give way to the roundabout, and gaps between batches would allow traffic from the secondary non-signalled entrances in. If traffic is directed in such a way that the smaller entrances are not heavily used, the gaps would be sufficient to absorb traffic from secondary entrances. If possible, some entrances might even be blocked off like Hoche and Carnot.The Champs Elysées and Grande Armée generates about 75% of the roundabout traffic. They are already prioritized by the stoplights which stand ahead of the circus. Putting stoplights inside the roundabout would have as only effect to block the access for the 10 other avenues. That wouldn't serve any other purpose.

And as it's been already said, Place de l'Etoile is both fluid and safe. The points generating congestion are Porte Maillot and Place de la Concorde. Why trying to fix it when it works?

I will surely drive on Place de l'Etoile next time I go to Paris! However, I'd like to ask something: how is it indicated that it is not a roundabout? Just a lack of a standard roundabout standard sign (the blue circle with tree curved arrows)?

By the way, I had a brilliant idea: to relocate the Arc de Triomphe elsewhere, built a 6-level (3 overground + 3 underground and a "pedestrianized area" at ground level) urban interchange integrated with a new arc 110m high with scenic lifts and vantage points :D

The extra queue space that you need because of stoplights also takes up land. That land isn't necessary with roundabouts.

Are you thinking that roundabouts don't take up land?

The extra queue space that you need because of stoplights also takes up land. That land isn't necessary with roundabouts.

Its easier to squeeze a turn lane into the existing right-of-way than it is to buy the properties surrounding a corner to make a traffic circle

It Paris there are so many cars with bumps and scratches, much more than in London or Manchester...

Its easier to squeeze a turn lane into the existing right-of-way than it is to buy the properties surrounding a corner to make a traffic circle

But the video shows that you don't necessarily need a traffic circle.

You could try this lovely one from Swindon

http://2.bp.blogspot.com/_DrvImR2-8Eg/TPkixynZ7KI/AAAAAAAAAJ8/VpmveZafz88/s640/3.JPG

how to use??

In the UK there are loads of roundabouts with traffic lights.

In Figueira da Foz, Portugal, there is a big lack of traffic lights, there are quite a few juctions that could do with them. There is especially one roundabout that is constantly getting gridlocked at peak hours, it is a t junction, so the roundabout could easily be removed.

http://maps.google.pt/?ie=UTF8&ll=40.159769,-8.858272&spn=0.001154,0.002411&t=k&z=19

Also, there are two major roundabouts that need traffic lights

http://maps.google.pt/?ie=UTF8&ll=40.164191,-8.858207&spn=0.001154,0.002411&t=k&z=19

http://maps.google.pt/?ie=UTF8&ll=40.164465,-8.851172&spn=0.001154,0.002411&t=k&z=19

http://maps.google.pt/?ie=UTF8&ll=40.164465,-8.851172&spn=0.001154,0.002411&t=k&z=19

However, in Portugal on roads though villages there are many many traffic lights that only serve the purpose of slowing traffic down, which is a bit of a waste of money and energy, I think that a speed bumps could do the trick.

imo stoplights help people crossing road at the next intersection nearby that has no stoplights, they can make the traffic flows breaking for a while

A city full of nothing but roads and roadabouts-how do you cross the street as a pedestrian? these roads have to be fairly calm ones if you want roundabouts.

Its one thing to remove all traffic markings from some experimental suburb or residential district if it means drivers will be more alert and won't take the ability to easily cruise at high speeds down arterial roads for granted. But okay whatever...I'm sure because of their lack of signals African or Indian roads represent the safest and most civilized driving experience in the world :lol:

There's the theory of Shared Space (Hans Monderman) who proves it can be more efficient and less dangerous to take out all signing and all devision of trafic flow (car lane, bicycle lane, pavement) in the range of travel that we are prepared to show 'social driving behaviour' - that is, roughly the first and the last 5 minutes of trip (for more about 'when to use' read the work of Monderman)

The idea is: strict framework creates inflexible flow.

There are several 'Shared Spaces' designed to this principle (one could call Place Charle de Gaule (Arc de Triomphe) in Paris one), among other in Groningen (NL). Monderman had a habit of showing the effect of this principle by crossing spaces backwards, and pointing out not only he was not hit by anything, but traffic moved around him fluently without irritantion (horning etc).

This also has the architectural result the space can be in certain occasions no longer strictly diveded in several independent subspaces (pedestrian space, car space, bicycle space, and mix spaces like zebra crossings) but can be designed as one single space, where the relation between different traffic-units is negociated on the spot.

Unfortunately Hans Monderman died a couple of years ago, but his work is still very influencial.

An intersection co-developed by Monderman
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^^ This idea of shared spaces could work well on quiet residential streets, but I hate when they try to apply they to larger areas. It has become widespread in many Dutch cities' downtown areas, where they usually created a "perimeter road" or something alike, meant to circulate traffic coming/going to other parts of the city, along which usually most parking garages serving downtown are built. Then, they "downgrade" downtown roads, level sidewalk with carriageway and remove segregation of bike lanes.

As a result, those streets become either clogged or people stopping driving there (and clogging traffic elsewhere to park), parking on the some garage on the "parking route" - each medium or large Dutch city will sign a "route" designated to take you through parking lots meant to serve the core downtown in a way you are supposed to park and walk sometimes as much as 10 minutes to get to your destination -. Some people will say it is "good" that traffic goes down, but that have widespread repercussions, from demise of certain business (or their relocation elsewhere) to annoyance and frustration when looking for scarce street parking.

Groningen performed this "art" to one of the most stupid levels I've seen in this country. It contends with Nijmegen for worst downtown traffic plan in my opinion. Rotterdam has by far and large the best downtown traffic management, but it is a particular case of a downtown rebuild from scratch after WW2. Einhoven, which was not destroyed in WW2, has the 2nd best downtown traffic management plan.

Here is one in NYC that works very well with stoplights. And very pedestrian friendly too.


http://images.travelpod.com/tripwow/photos/ta-00ae-2312-e679/columbus-circle-new-york-city-united-states+1152_12882331254-tpfil02aw-1419.jpg

http://www.changeyourlightsplantatree.com/images/Columbus-480x318.jpg

http://www.pksb.com/blog/wp-content/uploads/2009/10/cc.03.jpg