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Modern roundabouts: Safer, more efficient and environmentally friendly

September 21, 2020 08:00 AM
By: Daryl St. Clair

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​Modern roundabouts continue to gain in popularity throughout the United States, primarily due to their proven safety benefits over traditional signalized and stop sign controlled intersections. However, they are also typically more operationally efficient and more environmentally friendly.

The modern roundabout first appeared in the U.S. in the early 1990s and are not to be confused with the older style traffic circles, such as those that were constructed throughout New Jersey in the 1960s & 1970s. Roundabouts are designed and operate quite differently including flared entries and having the entering traffic yield to the circulating traffic.  They provide up to 30% more vehicle throughput than similarly sized signalized intersections during peak traffic volumes.

They are also environmentally friendly as they are yield-controlled on entry, so vehicles may continually flow through the intersection, especially during off peak hours. This reduces emissions from stopped vehicles. Additionally, they typically have landscaped central islands which make them aesthetically pleasing.

Regarding the safety benefits, PennDOT studies of data through 2019 have shown a 100% reduction in fatalities, a 77% reduction in injuries, and a 24% reduction in crashes.

Nationally, more than 5,000 roundabouts have been built in the past 30 years. As for Pennsylvania, we have built 70 roundabouts with 56 of them on State Routes. More than 40 more are under design.

Visit the Roundabout page of our website for additional information and informative videos.

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