Tuesday, March 10, 2009

Roundabouts

The topic of roundabouts came up recently. I have been told that when Highway 83 in front of my parents house gets reconstructed in 2012 or 2013, a roundabout will be constructed at the intersection of Highways 18 & 83. Here is a little back ground I found on roundabouts that some may find interesting.Introduction to Roundabouts
Each year, cities receive numerous requests to reduce the traffic congestion on their streets. Citizens also express concerns about the safety of the streets on which they live. In an effort to find appropriate ways to deal with these concerns, reduce traffic congestion and improve safety, many cities have begun considering the use of "roundabouts."
Roundabouts are used extensively throughout Europe, and in many other places around the world, to reduce accidents, traffic delays, fuel consumption, air pollution and construction costs, while increasing capacity and enhancing intersection beauty. They have been successfully used to control traffic speeds in residential neighborhoods and are accepted as one of the safest types of intersection design.
Why Use a Roundabout?
Safety--Roundabouts have been shown to reduce fatal and injury accidents as much as 76% in the USA, 75% in Australia and 86% in Great Britain. The reduction in accidents is attributed to slower speeds and reduced number of conflict points.
Pedestrian Safety--All research suggests that modern roundabouts are safer than signalized intersections for pedestrians. This safety advantage has been attributed to the slower traffic speed at roundabouts and the division of the pedestrian crossing into two stages, from the near-side wheelchair ramp out to the splitter island, and then from the splitter island to the far-side wheelchair ramp. In each stage the pedestrian has to look in only one direction to cross a one-way traffic stream. Pedestrian refuges are provided in the areas within the splitter islands.

Low Maintenance--Eliminates maintenance costs associated with traffic signals which amount to approximately $3,500 per year per intersection. In addition, electricity costs are reduced with a savings of approximately $1,500 per year per intersection.

Reduced Delay--By yielding at the entry rather than stopping and waiting for a green light, delay is significantly reduced.

Capacity--Intersections with a high volume of left turns are better handled by a roundabout than a multi-phased traffic signal.
Aesthetics--A reduction in delay corresponds to a decrease in fuel consumption and air pollution. In addition, the central island provides an opportunity to provide landscaping. How to Drive a Roundabout
As you approach a roundabout there will be a YIELD sign and dashed yield limit line. Slow down, watch for pedestrians and bicyclists, and be prepared to stop if necessary.

When you enter, yield to circulating traffic on the left, but do not stop if the way is clear.

A conventional roundabout will have ONE-WAY signs mounted in the center island. They help guide traffic and indicate that you must drive to the right of the center island.

Upon passing the street prior to your exit, turn on your right turn signal and watch for pedestrians and bicyclists as you exit.

Left turns are completed by traveling around the central island.

2 comments:

Rodge said...

I really enjoyed this piece on round a bouts. I knew some of this information already but it was nice to learn more, especially from a civil engineer with references. Bring on the round a bouts.

Anonymous said...

Look kids, there's parliament, Big Ben.

-Bubs