Wednesday, November 28, 2012

Is it Time for Traffic Lights at Intersections to Go?

Traffic lights giving way to roundabouts(The Local, Mar. 11, 2011)

Also discussed here: The long wait at the many unnecessary traffic lights in Germany may soon be over(World Streets, Nov. 15, 2012)

And here: Roundabouts & Emissions- Monmouth County, New Jersey(16 slide PowerPoint)

And here: Modern Roundabouts, Global Warming, and Emissions Reductions: Status of Research, and Opportunities for North America (16 page Word document, Tony Redington, New Hampshire Office of Environmental Protection)

And here: Comparing costs of roundabouts and traffic signals(travis baker, Road Warrior, Sep. 25, 2012)

And here: Roundabouts - Frequently asked questions (FAQs)(Wisconsin Department of Transportation)

More and more evidence shows that when an intersection with traffic signals is replaced with a modern roundabout, vehicle emissions drop and safety for both pedestrians and those in vehicles increase significantly. Today we review news from Germany that a country-wide switch is being considered along with some modeling assessments from Vermont in the USA that indicate that roundabouts could play a critical and inexpensive role in meeting greenhouse gas targets (assuming that the national government ever adopt stringent ones). On sheer economics, there is no contest. Roundabouts have an initial installation cost less than that for traffic lights (roughly $250 K) and an ongoing operational cost that is almost negligible (the cost of electricity alone is approximately $1,000/year for traffic lights at each intersection).

 Key Quotes:

  “traffic lights provide a false illusion of safety, pointing to the dangers of impatient drivers and children who cross the street despite there being a red light”

“Today, an estimated 100,000 intersections in Germany are controlled by traffic lights. But the trend toward roundabouts is undeniable…Between 30 and 50 percent of the traffic lights could be replaced”

“Cologne…has replaced 200 traffic lights with roundabouts and zebra stripes in the past several years, a move which could save the city almost €4 million in energy and maintenance costs..A further 90 traffic light eliminations are still expected”

 “[in Vermont, USA] hypothetical installation of roundabouts in place of signals at 100 busy intersections.. would decrease total annual motor fuel use by approximately 8% of 1997 statewide consumption.. “

 “The immediate GHG reduction from the replacement of 25 traffic signals at busy intersections to roundabouts would represent about 24% GHGs reduction necessary for Burlington to return to 10% below the 1990 generation levels by 2005”

 “roundabouts typically achieve:
  • A 37 percent reduction in overall collisions
  • A 75 percent reduction in injury collisions
  • A 90 percent reduction in fatality collisions
  • A 40 percent reduction in pedestrian collisions”
“Anything but a roundabout generates serious injuries at a 900% greater rate (Insurance Institute of Highway Safety study of US roundies 2001). A fatality occurs once a year per 135 signals, about six die at signals today while the French roundabout rate (over 30,000 roundabouts there) would drop that would drop that to about one....Plus roundabouts do everything else better–less delay for all users, less energy use, less pollution, sharply increased walker safety, and less scenic blight, etc. (Tony Redington, Blog: Dec. 23,2011)
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