The Minnesota Department of Transportation (aka Mn/DOT) put together a procedure last year for determining the correct traffic control to be placed at their intersections, which the nicknamed "ICE." They put out a technical memorandum detailing what they are looking for, but it is pretty open ended. Today I attended a class put on by John Albeck, who was hired by Mn/DOT to teach a class on the new procedure. John did a good job of putting together a manual (which included once of my ICE Reports in the Appendix as an example!) and making a dry topic pretty interesting.
The new ICE Report is supposed to look at everything from do nothing to build an interchange. This includes changing access and implementing several "non-traditional" intersection types (like jughandles and Michigan Lefts). I expect the vast majority of ICE Reports will thoroughly analyze: do nothing, all way stop sign control, roundabout control, and traffic signal control. These are the standard intersection control options in Minnesota. Other options will be analyzed in those rare instances where one of the four standard control options doesn’t work well.
This procedure is going to replace the traditional Signal Justification Report procedure typically used. Mn/DOT is only rolling this procedure out for intersections on their highways, but just about everyone at the class expects the procedure will trickle down to the county and city level. The procedure is a good one. It forces engineers to thoughtfully consider all of the options.
Hopefully as a future traffic engineer, I will be able to conduct these tests myself and see which option is the best for the intersection. I have a question about roundabout controls. I don’t think my transportation engineering design course ever mention it. What is it exactly? I have only learned about the do nothing, all way stop signs, and stop lights control, but never heard of the roundabout control. Can you provide an explanation on what this is?