I dunno, growing up in california, I just view roundabouts as a cheap and dangerous alternative to real interchanges. Nothing beats a well designed cloverleaf...

Waaah, that's out West, pardner, where you got all that spaaaace, and all them thar deer and anteelopes.

If there's any excuse for how hosed up some of Boston traffic/rotaries are, it's that they were constructed in the 20s and 30s literally as recreation roads for Sunday drives for the 200 or so people in town who owned cars. Roads like the scarred-tree-lined Jamaicaway slowly became major commuter arteries without anyone noticing or changing anything. Many of those old MDC roads run through dense neighborhoods where there's no room to expand.

I think anyone looking for a representative driving experience there should fly into Logan, rent a car, and drive through the Sumner/Callahan then follow Storrow drive out towards Brighton during mid-day traffic. Fun for masochists!