This photo shows the Millennium "Trail" at Gude Drive and Research Boulevard, just on the west side of the 270 bridge, on 2012-03-18. Construction has blocked the trail with no ramp and no alternative but to use the shoulderless Gude Drive to get around the blockage. I had to haul my bike up the high curb (i was traveling eastbound). A wheelchair user would be totally and completely screwed.
Montgomery County's bicycle infrastructure is just abysmal. The Millennium "Trail" is a prime example. Along Gude, it's really just a sidewalk paved with asphalt, with frequent cutouts for driveways. There's very little signage to alert drivers that there's actually a trail there. Another example in that area is the bike lane along Route 28. Sometimes there's a lane, sometimes there isn't. There's no signage at all; you can just tell it's a bike lane from the markings at intersections, where right turn lanes for cars go to the outside of the bike lane (e.g. see Key West Avenue at Medical Center Drive). The lane abruptly ends in places, apparently crossing to poorly maintained asphalt trail on the other side of the road, again with no signage at all.