A few weeks ago I noticed a sign on Route 16:

This sign is not supported by the law. Specifically, MGL 85.11b says:

Every person operating a bicycle upon a way, as defined in section one of chapter ninety, shall have the right to use all public ways in the commonwealth except limited access or express state highways where signs specifically prohibiting bicycles have been posted

Yesterday MassDOT called me to say that Route 16 is not a "limited access or express state highway". I wrote to the Cambridge Bicycle Committee and they told me the signs belonged to the Department of Conservation and Recreation and that "both Cambridge and MassBike requested that the signs come down back in April". I've now written to the DCR; we'll see what they say.

Update 2012-09-26: The DCR didn't get back to me, but the did take down the sign!