Today’s output from Blogistan Polytechnic Institute’s state-of-the-art HEMMED (High-Energy Meta Mojo Elucidation Detector) machine is a big circle. With animation!!

Today we will be discussing roundabouts. Roundabouts are one of those little things that can add up to big things as we start moving towards a Sustainable Future — one where we reduce our dependence on non-renewable fuel and reduce our negative impact on our planet’s climate.

A roundabout is a “type of circular junction in which road traffic must travel in one direction around a central island.”


Roundabouts have been used in Europe for many years and are becoming more common in the United States. Some early variations have been called traffic circles or rotaries but the preferred engineering term is roundabout. In my community and nearby communities, roundabouts are being used to tame difficult traffic patterns to make them safer and greener.

Roundabouts move traffic safely through an intersection because of:
– Slower speeds
– Fewer conflict points
– Easier decision-making

Studies by the Insurance Institute for Highway Safety (IIHS) show that roundabouts provide a:
. 90% reduction in fatal crashes
. 76% reduction in injury crashes
. Some reduction in pedestrian and bicycle crashes

One of the drawbacks to roundabouts is that they require more space and are more expensive to build. The physical space needed for a roundabout is much larger than the physical space needed for a four-way stop. For example, in my community we have a crying need for better traffic control at an intersection that is on the road that has the post office, library, main city park and swimming pool. However, that intersection has homes on two of the corners and, quite literally, they would have to either buy out the owners or the homes would have cars zooming within two feet of their living room window. When designing new roads for new communities or neighborhoods, the larger footprint can be taken into account.

Another drawback is re-training. Everyone knows (more or less) what to do at a 4-way stop. Except for the occasional “did they stop before I did?” there is little doubt involved. With a roundabout, the concept of “keeping moving” can be a little nerve-wracking at first. However, the low speeds in the roundabout (recommended speed is 15 miles per hour) make it easier to adjust and also easier to make eye contact with other drivers so that your and their intent is clearer. When our new roundabouts went in, I was sure it would be a mess but, much to my surprise (and delight) it was not. People adjusted well and the only issues were when drivers were going too fast.

The Federal Highway Administration provides this information about building and maintaining roundabouts:

While initial construction costs can be higher with roundabouts, they often have lower operating and maintenance costs than signalized intersections. They can have ongoing costs for lighting and maintaining the landscaping, but unlike a signalized intersection, there is no signal equipment to install, power, and maintain. Roundabouts have longer service lives than traditional intersections resulting in better economic value over the long term, especially when you factor in the reduction of fatal and injury crashes.

Roundabouts are also the greenest intersection alternative and not only because of their aesthetic appeal. Reduced vehicle idling means fewer emissions and less wasted fuel. Less acceleration and fewer sudden “hard stops” means quieter, more peaceful transportation through communities. Landscaping in the central island, splitter islands, and along the approaches can further benefit and enhance community livability.

Here is a helpful web site from the State of Wisconsin about roundabouts including:
How roundabouts work including videos and animation
Benefits of roundabouts including information from the National Cooperative Highway Research Program (NCHRP)
– A roundabout FAQ which includes photos of the old traffic circles.

The town I grew up in had a traffic circle in its downtown area which was not only a way to move traffic but a point of reference for the community. Certainly attractive but not nearly as functional as the more advanced roundabout designs:

(By the way, small towns really like their “guys on horseback” statues. This one was Lafayette who was pretty popular in Massachusetts because of his assistance during our Revolutionary War.)

Beyond the safety considerations, the Green Impact of roundabouts is important as we start looking for more and more little things to add up to a cleaner environment and reduced dependance on non-renewable energy sources. Here is a little factoid on what a simple thing like idling at a stop light does::

…one element in tailpipe emissions can’t be “cleaned up” – carbon dioxide (CO2). This is the principle greenhouse gas linked to climate change. Every gallon of fuel that is burned produces about 20 pounds of CO2. The bottom line: the more fuel you use, the more CO2 you produce. And one of the best ways to cut fuel consumption is to avoid idling. After all, it gets you nowhere.

The cost of idling your vehicle for 10 minutes every morning can add up. You use about 0.026 gallons of gasoline for every 10 minutes, which costs us about 5 cents. This adds up to about 9.5 ounces of Carbon Dioxide for those 10 minutes.

Think about every minute spent idling your car waiting for a green light and multiply it by the number of cars and intersections in our country. I could not find any exact numbers on this but if the average driver stops for an average of 1 minute at about 15 stop lights a week, that would add up to 780 minutes a year: 2 gallons of gas and 46 pounds of CO2. It is estimated that there are 210 million cars on the road. If even as little as 1% of the idling (27,300,000 hours) could be eliminated, saving 4,258,800 gallons of gas and 97,256,250 pounds or over 48,000 tons of CO2.

Another one of those little things that can start to add up.


Look around (and around) for ways to Go Green and give us a few more years on Planet Earth. When issues like traffic control come up in your community, encourage the city planners to look at roundabouts as another small change that will add up.

Happy Thursday to everyone! And fist bumps!

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