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Do you support NH efforts to create more roundabouts?

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The N.H. Department of Transportation (NHDOT) is making an effort to build roundabouts at certain intersections across the state. Click here to learn more

There is a difference between a roundabout and a rotary or traffic circle.

A rotary/traffic circle is a type of intersection that directs both turning and through traffic onto a one-way circular roadway. Rotaries typically feature high speeds inside the circle and on the approaches and exits.

A roundabout is also a one-way circular roadway with approaches and exits, but its diameter is tighter than a traffic circle, forcing motorists to navigate the road at a slower speed.

NHDOT is using the roundabout concept to replace intersections that had been controlled by traffic signals. Roundabouts are also being used to replace traffic circles, which occurred in Lee in 2015 at the confluence of routes 4 and 125.

New Hampshire, according to transportation officials, has 40 roundabouts and the number is growing. A roundabout, for instance, will be built in Dover to replace the traffic signals at the intersection of Route 4 with Spur Road and Boston Harbor Road, near the entrance to the Spaulding Turnpike (Route 16).

Traffic engineers say traffic circles, because of the higher speeds, are dangerous because of the chance of high-speed accidents that risk injury and death. They also argue that certain signaled intersections are equally dangerous because of the risks of serious rear-end collisions.

Roundabout proponents say they have a more calming effect on motorists, maintaining traffic flow through an intersection but at slower speeds, thus reducing accidents that cause injury or high property damage.

Opponents of roundabouts say they can be confusing to motorists, thus creating a greater opportunity for accidents. Their slower nature can also create congestion and stop-and-go traffic, raising the chances of rear-end collisions.

Are roundabouts a good idea? Tell us why in the comments section below.


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Roundabouts are bad news. They cause confusion as well as delays for motorists. Their small size causes major problems for tractor trailers. I assume they are significantly cheaper than exit ramps, but I don't think the savings are worth it. In the long run I think they will also likely cause more accidents than the corresponding stop lights.


Modern roundabouts are designed for trucks, large vehicles, and trailer towing vehicles by including the center flat area around the circle. It’s not a sidewalk, it’s called a truck apron, and it’s for trucks to begin a sharp right or end a left or U-turn on. But they should obey the warning speed and know their vehicle.

Roundabout Trucks Videos:
STAA, Porterville, CA:
Washington County, WI:
Windsor-Essex Parkway, Canada:
WSDOT simulation:


No I Do not Support them a waste of money an resource's an just make things worse


First cost is the wrong way to compare projects. It would be like buying a car without knowing the fuel economy or safety of the thing, just its price to buy.

Present Value Life Cycle Cost Analysis (LCCA) is the best way to compare two or more choices. When comparing modern roundabouts to signals for a 20-year life cycle (the standard period), modern roundabouts usually cost less. Costs to compare include: first cost (design/land/construction), operation and maintenance (electricity, re-striping, upgrades, etc.), crash reduction (what’s your/your family’s safety worth?), daily delay (what’s your time worth?), daily fuel consumption (spend much on gas?), point source pollution (generated by stopped vehicles = health cost), area insurance rates (this costs more where it is less safe to drive). Each of these things, and others, can be estimated for any two choices and everyone near or using the project area will pay some portion of all of these costs (and also gain benefits).


Modern roundabouts are the safest form of intersection in the world - the intersection type with the lowest risk of fatal or serious injury crashes - (much more so than comparable signals). Visit the Insurance Institute for Highway Safety for modern roundabout FAQs and safety facts. Modern roundabouts, and the pedestrian refuge islands approaching them, are two of nine proven safety measures identified by the FHWA.

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