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Opinion - Roundabouts for Anchorage |
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As an engineer with knowledge of roundabout design, I'd like to describe why modern roundabouts may be a good solution for some of Anchorage's problem intersections and let people know where to get more information. No one doubts that we have problem intersections that must be improved. It is an extremely rare day in Anchorage when there is not at least one crash. Some of those crashes kill or maim our citizens. During peak hours, we experience congestion on almost all of our main roads. Anchorage spends a lot of tax money to improve safety and reduce congestion. Over and above the initial construction cost, each traffic signal costs us between $8,000 and $15,000 every year for electricity and maintenance. The Municipality of Anchorage Office of Planning, Development and Public Works, and the Alaska Department of Transportation and Public Facilities are the two local agencies responsible for our intersections. Traditionally, these agencies have used 2-way stop, 4-way stop, and signals to solve safety and capacity problems. In recent years, our transportation agencies have been taking a fresh look at traditional solutions. Modern roundabouts are being considered for Alaskan roads because they have been proven to be safer, more efficient and less expensive than other forms of intersection control. The Insurance Institute for Highway Safety published a before-and-after study of intersections converted to modern roundabouts in a mix of urban, suburban and rural settings in numerous states across the nation. [ Read the report. - PDF Format ] They reported a 39 percent decrease in crashes overall, and a 76 percent decrease in injury-producing crashes. No fatalities had occurred after the conversions, so the study projected fatal and debilitating crashes will be reduced about 90 percent. In addition to improving safety, most of those intersections actually convey more traffic after the conversion. Other studies in the US and overseas reported similar findings. Given statistics as powerful as these, our local transportation agencies would be irresponsible if they ignored these potential safety and capacity benefits. There is every reason to believe Anchorage drivers can adjust to these new intersections. Modern roundabouts have simple rules and are simple to use. There is a yield sign at every entrance. Drivers that are already in the roundabout have the right-of-way over any driver entering the intersection. Approaching drivers slow down, yield, and then enter a roundabout in a manner very similar to the right-turn-on-red maneuver that thousands of Anchorage drivers do every day. Our transportation agencies are working hard to solve intersection problems. Our drivers have responsibilities too. Intersection designers are powerless to correct problems caused by drivers who run stop signs and signals, fail to yield, or drive too fast for road conditions. For traffic signals to work, drivers must stop for red lights. For modern roundabouts to work, drivers must yield at the yield line. The difference is, as studies have clearly shown, that drivers who run stop signs or signals at traditional intersections are significantly more likely to hurt or kill someone than drivers who fail to yield at roundabouts. Our local transportation agencies are taking a sensible approach. No one has suggested that modern roundabouts are appropriate for every intersection. The Southport location was chosen very carefully. First, modern roundabouts have a proven record in solving the sight distance, pedestrian crossing, and speeding problems that were present at the intersection. Second, drivers in that neighborhood have efficiently used the 4-way stop at 100th Avenue for many years and it was reasonable to believe they could adapt those skills to a modern roundabout. A great deal of study and research was completed before, during and after the first roundabout was constructed. Lessons learned by other cities were applied. During the first year of operation, engineers actively monitored conditions in the intersection and collected a lot of feedback, both positive and negative, about the Southport Drive project. Small refinements were then constructed to improve the intersection. The study will continue, and the Southport Drive roundabout will help us continually refine Anchorage's design guidelines to best fit our local weather conditions, maintenance procedures, the limitations of our short construction season, and Alaskan drivers. Future roundabouts in Alaska will benefit from this experience. Local intersection designers are working hard to refine modern roundabout designs for Anchorage conditions. Local drivers also have a job to do. Learn the yield rules and when to signal. If you think a modern roundabout is the same as an old-style traffic circle, learn what makes them different. Traffic circles date back to the early 1900's and are common in Washington DC, and many eastern states. Modern roundabouts, a refinement of old-style traffic circles, were first used in England in the 1960's. Modern roundabouts are superior for several reasons. The yield-at-entry rule clearly establishes which driver has the right-of-way. Other design refinements control speed much better, and eliminate lane changing and weaving maneuvers inside the circle. Modern roundabout design refinements were so successful that they are replacing signals, stop signs, and old-style traffic circles all over the world. In the U.S., modern roundabouts are also spreading very quickly as Americans become familiar with the capacity and safety benefits. Since the first modern roundabout was constructed in the US in 1990, nearly 300 more have been built, according to Federal Highway Administration (FHWA) estimates. For more information about modern roundabouts set your search engine to "modern roundabout" or visit www.alaskaroundabouts.com. With potential benefits including better traffic flow, 39 percent fewer crashes, and 75-90 percent fewer injuries and deaths, modern roundabouts should be given a real opportunity in Anchorage. Written by
Joel Stout, a professional engineer with Lounsbury &
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