I appreciate Mr Schamp's sense of humor. That was quite a funny presentation!
I wrote a big paper on roundabouts for my last quarter at school. I wasn't required to go very deep into the research, but I focus more on how we changed from circles, like Dupont Circle, into rotaries (like those in Massachusetts), before we got into the early "modern" roundabouts along I-70 in Colorado (particularly those at the Vail junction).
One thing I noticed was that the early modern roundabouts were
very British. Short of driving on the left, they were basically just flipped versions of their roundabouts. This extended to basic practices like not having lane lines through the circle, or flaring the entry roadway from one to two or three lanes to maximize throughput at the circle. The practice of "flaring" seems to have died down a bit.
I bring this up because, in the presentation that Mr Schamp gave, he talks about the "honeymoon" years with their early roundabouts, particularly those along Britton Parkway (oddly enough,
a roundabout corridor in Lacey, WA as well). He doesn't go into great detail about what exactly he means by this, but I think it's in reference to them just building a bunch of roundabouts, several quite large examples, and not really paying attention to crash data (with the child-rearing years being where they started to notice serious issues). I wouldn't want to suggest that those early roundabouts were somehow superior to the modern FHWA-compliant designs, but what changed at roundabouts, particularly those designed prior to 2009, to those that we we've seen built since the current MUTCD was released? As far as I can tell, the discussion around crashes has only come up majorly in the last ten years, despite 2x2 modern roundabouts having existed in sizeable numbers since the mid-90s.
When I look at some of the older notable roundabouts:
* Long Beach (Los Alamitos) Roundabout: no major changes after major modification in mid-90s.
* Vail roundabouts: some lane lines added
* Avon roundabouts: one entry (of dozens) narrowed; some lane lines but they frequent disappear
* Summerlin, NV (Town Center Dr): right lanes changed to right-only
* Lacey, WA (Britton/Marvin/Willamette): slip lane added, exit lines added (notable because it was in
this early video).
So there have been some changes at these roundabouts, but not really anything major. The newest of these (Lacey, WA) was constructed eighteen years ago; collectively, they've experienced well over 100 years of crash data.
I guess, in short, it's funny how some of the roundabouts that have seen the most number of changes seem to have been those built since 2009.