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I’m sorry, but your project is wrongheaded.

We have lots of roundabouts here in Kansas, and they work exactly as intended: traffic can flow smoothly through heavily traveled intersections without backing up as at traffic lights. In areas with heavy pedestrian traffic traffic lights are superior to the combination of roundabouts and pedestrian-right-of-way crossings, but in areas where it’s basically all vehicles, roundabouts are much better than traffic lights, any combination of stop-signs, or uncontrolled grade intersections.

I currently live in NJ, and we've had roundabouts or circles for a 100 years, and are getting rid of them. They are fine when traffic is light, but really bite when it gets heavy and steady. So, NJ is slowly adding overpasses and other tricks to keep the heavy traffic out of the traffic circles.

We took a drive through the midwest this summer. Richfield MN has circles in the city, but they are miniscule and everybody has to slow way down to get around. It's not a horrible deal if they are used instead of bumps to slow cars, but it snarls traffic during the rush.

It was in western MN, heading toward SD, that I found the real puzzle. Driving down a 2 lane highway, we came to a traffic circle that required the semi-trailers to slow to about 15 mph in order to be sure they could get through without running their wheels up over one curb or the other. This was on a sunny summer day. I'd be interested to see how well that works in the ice and snow of winter.

When a traffic circle works for smooth flow, it has to be big enough to not give carnival ride type G forces when you go around it at traffic speeds. The traffic circle near me has a median of about 100x200 feet. You can go around this at 35 mph without a worry, and that was maybe the general traffic speed when the road was built.

But the tiny traffic circles I saw in MN have nothing to do with smooth flow of traffic, and should have no place on heavily traveled roads.

I hope Kansas did it better.