"Bicycles stop on GREEN" ??

I was riding along on route 6 in Seekonk, MA the other day (on the
shoulder
as usual) and came to a red light at a 4-way intersection. Pulled up
behind someone and noticed a sign on the side of the road reading
"Bicycles stop on green". What is that supposed to mean? How are you
supposed to stop on green (and why the hell would you want to)? Am I
missing something? Needless to say I did NOT stop on green, as that
is rediculous and stupid along with being dangerous (are you supposed
to proceed on RED??). Also, since I noticed that one sign i've seen
several along US 6, but only in MA. Anyone have any info on them (and
their meaning) before I email MassHighway?

Thanks.