The answer to that question is probably not, but I had to get you in the doorway. I am certain that people who do not read this article will be all over me in social media. In reality, there is likely not one singular solution that will save us. However, you might be surprised to learn that traffic roundabouts can be a piece in a much larger puzzle for helping improve poor air quality and mitigating carbon emissions. Here’s why.
Until the past few years, my experience with roundabouts was mostly confined to the hilarious scene in the movie National Lampoon’s European Vacation. Chevy Chase’s character gets stuck in a roundabout and keeps going around in a roundabout near Parliament. The modern roundabout concept originated in the 1960s. We can actually thank (or curse depending on your perspective) the United Kingdom. It has been widely employed in many countries including the United States.
Within the county that I reside, roundabouts (the “old school” term is traffic circles) are popping up everywhere in recent years. Clearly, transportation planners in Georgia have embraced them. Like many of you, I have occasionally complained about people who clearly do not understand how to approach one or yield. However, the Insurance Institute for Highway Safety (IIHS), an independent, education andnonprofit scientific organization, reveals several benefits of roundabouts on its website. They include:
- Safer alternative to stop signs and traffic signals
- Better traffic flow
- Safer crossings for pedestrians due to reduced speeds
Several studies have found that roundabouts in places formerly populated by traffic lights or stop signs reduced injury crashes by up to 80 percent.
However, there is a hidden benefit of roundabouts that interests me as an atmospheric scientist. Study after study confirms that roundabouts reduce fuel consumption at intersections, carbon emissions and delay times. I spent the first 12 years of my career at NASA, but it does not take a rocket scientist to know that reductions in carbon emissions or fossil fuel consumption are a good thing. The graphic below illustrates contemporary trends in atmospheric carbon dioxide over the past several decades.
I want to highlight a study discussed by the Environmental Resilience Institute (ERI) at Indiana University. Its website notes, “Since 1996, Carmel (Indiana) has converted more than 120 intersections to roundabouts….resulting network of roundabouts has saved Carmel money, reduced vehicular emissions, improved air quality, and enhanced community walkability and traffic safety.” Specific outcomes relevant to air quality and improvement and climate change include:
- 24,000 gallons of gas saved annually due to a reduction in engine idling and traffic congestion. The study estimates, according to ERI, a savings of over $7 million per year at $2.50 per gallon.
- Signification reductions in nitrogen oxide, which causes health challenges such as respiratory problems. Transportation emissions are a major contributor to nitrogen dioxide emissions.
- Lower transportation infrastructure footprint which led to less land development and minimization of resource usage. Such activities can be carbon-use intensive.
It’s the second bullet for me. Many communities of color or impoverished areas disproportionately suffer from upper respiratory ailments. According to the Department of Health and Human Services (2019) website, “Non-Hispanic African Americans were 40 percent more likely to have asthma than non-Hispanic whites….non-Hispanic black children had a death rate eight times that of non-Hispanic white children.” Irrespective of race, child poverty is strongly correlated with adverse health outcomes associated with respiratory ailments according to medical experts. Roundabouts could be a great alternative in such vulnerable communities.
Studies show that U.S. drivers are not big fans of roundabouts, but perhaps this information will cause us to “circle back” on them.
#Traffic #Roundabouts #Save #Climate #Change