Georgia DOT considers three new intersection designs
Road design is a big factor in preventing auto and truck accidents, personal injury and wrongful deaths in Georgia and around the world. In my practice as a personal injury trial attorney in Atlanta, it is clear to me that prevention is the best approach.
According to an article by Ariel Hart in today’s Atlanta Journal Constitution, the Georgia Department of Transportation is considering three new intersection designs to relieve traffic congestion for minimal cost. The ideas are intriguing but I wonder how Georgia drivers will adjust to these unfamiliar designs.
- Diverging Diamond design, planned initially for the Ashford-Dunwoody Road exit on I-285, will will make traffic in both directions cross over to the left side of the road as it approaches the bridge over the interstate. After the bridge, it crosses back to the right, so that drivers who want to turn left will be in the far left lane. Originating in France, it has been implemented once in the U.S., in Missouri. Here are an aerial view and a driver’s view of a diverging diamond intersection in operation. Popular Science sings its praises. But as with any unfamiliar traffic design feature, crystal clear signage to inform drivers of what’s coming is absolutely critical.
- Continuous flow intersection design (CFI), planned for intersections in Gwinnett and Dawson counties, is also called a crossover displaced left-turn (XDL). This innovation is an at-grade intersection that moves the turning vehicles, conflicting with the through-movements (to the left where traffic drives on the right, and vice-versa), out of the main intersection. Here is an animation of how a continuous flow intersection works.
- Roundabouts are old news in Europe but have just been catching on in the US. Also known as a "traffic circle", it is a type of circular junction in which road traffic must travel in one direction around a central island. Signs usually direct traffic entering the circle to slow down and give the right of way to drivers already in the circle. The benefit, according to the Insurance Institute for Highway Safety, is a 40% reduction in crashes, since roundabouts make traffic slow down and eliminate left turns entirely by sending all intersection traffic in a counter-clockwise circle. Roundabouts take some getting used to.
With good lights and signage adequate to overcome the problems of unfamiliar and counter-intuitive design, perhaps these innovations can help reduce accidents and congestion. I just hope GDOT doesn’t skimp on signage!
Ken Shigley, author of Georgia Law of Torts: Trial Preparation & Practice, is a Certified Civil Trial Advocate of the National Board of Trial Advocacy, and has been listed as a "Super Lawyer" (Atlanta Magazine), among the "Legal Elite" (Georgia Trend Magazine), and in the Bar Register of Preeminent Lawyers. He practices law at the Atlanta law firm of Chambers, Aholt & Rickard, and has broad experience in catastrophic personal injury, spinal cord injury, wrongful death, products liability, brain injury and burn injury cases. He is also president-elect of the State Bar of Georgia. Ken and This post is subject to our ethical disclaimer.