Washington Blvd from around the intersection with 50 all the way to Lee Hwy could use markings indicating that bikes can use the road. Not sure it is wide enough for dedicated bike lanes (I’m thinking of the segment between Glebe and the East Falls Church Metro), but I do see plenty of folks riding that road. I would note that traffic on Washington tends to be in 40 to 50 mph range between Kirkwood and the East Falls Church Metro. Increased speed enforcement would make it safer for everyone, but the police cannot be there all the time. Marking the roadway and thereby putting drivers on alert (one hopes) would be very helpful.