With regards to the strange piece of infrastructure in South Hadley: this is actually not a rotary/roundabout, but actually a traffic circle. The significant difference is that at some point in along the circle, traffic entering the circle is given preference. This is the more common cousin of the European roundabout that you often see in Massachusetts, as I’m sure you know. The one I’m most familiar with is the abomination on RTE 135 just between Wellesley and Olin College. Then there’s the perfect example of a traffic circle in the form of Columbus Circle in New York City. I feel like there should be drivers seminars to teach people how to negotiate both traffic circles and roundabouts….or at least signs that alert drivers to the cocaine up ahead. This isn’t a problem in Europe because most intersections of this sort are roundabouts and drivers don’t have to worry about the anomaly you came across. Either way, drivers should be aware of their surroundings – the psychological effect of forcing drivers to do so is what actually makes roundabouts safer to negotiate.