Ah, the speed of the internet: we were all set to write up the recent decision by the Supreme Judicial Court of Massachusetts in Sorenti Bros., Inc. v. Commonwealth, No. SJC-11420 (May 19, 2014), when we noticed that the good folks over at the Massachusetts Land Use Monitor had already done so.
So if the question of whether a gas station owner can recover compensation by virtue of the Commonwealth eliminating a roundabout and thereby (allegedly) impeding access to the station floats your boat, read all about it here: SJC Reverses Eminent Domain Judgment For Impacts From Sagamore Bridge “Flyover.”
One note: compare the way the SJC treats the issue with how the Supreme Court of Canada treated a similar (thought not exactly the same) situation.