Comments on: Urban Design: The Traffic Circle as a Space for Art

By: ruimtelijke ordening

ruimtelijke ordening — Sun, 05 Sep 2010 00:12:20 +0000

I think it would be better if you place trees there..

By: Daniel Pedersen

Daniel Pedersen — Fri, 02 Jan 2009 00:32:12 +0000

It appears that the widespread consensus is that I am wrong, and that traffic circles reduce pollution. See Bernard’s post above and this blog entry:

http://greeninc.blogs.nytimes.com/2008/12/30/roundabouts-efficient-or-annoying/#more-783

All of these claims that I’ve seen have not been substantiated, and I still haven’t seen any studies measuring the differences.

By: Bernard David

Bernard David — Mon, 08 Dec 2008 09:48:22 +0000

Let’s look at the wider picture. When urban traffic flows smoothly with minimal delays then there are fewer accidents. Methods to effect this are rapidly being adopted around the world. Where possible traffic circles instead of traffic lights are being installed. This is in spite of some inconvenience for pedestrians and neighbors. The advantages from fewer accidents, less delay and lower pollution outweigh the drawbacks. In many parts of the world right turns at traffic lights are permitted. This would also require improving the layout of our junctions which are very poorly planned especially pedestrian crossings which are placed much too close to the junction often preventing any flow of traffic. Another idea was tried by UPS. They program their routes to avoid left turns and save millions of gallons of fuel and speed delivery by this simple way of planning their journeys.

By: Karin Kloosterman

Karin Kloosterman — Mon, 08 Dec 2008 08:00:38 +0000

People accelerate hard at stoplights, too. Especially if you are in Israel and have someone honking at you to move.

By: Daniel Pedersen

Daniel Pedersen — Thu, 04 Dec 2008 07:45:59 +0000

Hmmmm, good point, but the emissions from idling are MUCH less than acceleration, especially the Israeli habit of accelerating HARD.
Then again, some of the cars accelerated out of the intersection that was there before the traffic circle.
On the third hand, I’ve idled away many an hour at traffic circles, too…
So I still think that on the balance, emissions would go up.

Would make a nice research project.

By: Karin Kloosterman

Karin Kloosterman — Thu, 04 Dec 2008 06:51:12 +0000

On the other hand, they save people from idling at stoplights. I think they cause less emissions over all, unless you live in Switzerland where you have to turn the engine off after 30 seconds of idling.

By: Daniel Pedersen

Daniel Pedersen — Wed, 03 Dec 2008 23:43:07 +0000

Another effect of traffic circles: I believe that they increase emissions from cars, especially hazardous particles from diesel engines. Accelerating out of the circle with a heavy foot on the gas causes strained operation of the engine, increasing the emissions.
If you want to reduce air pollution, go easy on the gas – when exiting traffic circles or otherwise.