DC sustainable mobility street signs
I think I have seen this Neighborhood Bikeway ("bike boulevard") bike route sign elsewhere in the city. This is off Nebraska Avenue. I can't say I like it all that much. I think that bike route signage needs a more coherent identity that should simultaneously market cycling. E.g., see Joseph Prichard's Better Bikeways signage project.
And I saw this sign on 34th Street NW by the Cathedral. I was really surprised because this is virtually identical (but slightly different graphically) to the same sign used in New York City to denote their special 20 mph neighborhood slow zones.
I don't know if DDOT put these up. In any case, in DC, such signs do not denote a zone with speed limits less than 25 mph. Also see "A Vision Zero agenda for DC."
Neighborhood slow zone signage in Brooklyn.