It appears as though they've finished renovating the park near where the W&OD crosses Columbia Pike. I've got to say, I'm impressed. First off, they included a bike work-stand (equipped with tools) which is certainly handy:
And even more impressive, they included a short section of winding trail that's off the W&OD itself:
The trail is a practice area for kids and other bike newbies to get used to practice riding the trail. It's been a while since we've had to teach a child how to ride a bike, but man, this would have been helpful.
Now, if we could only train the "experienced" bikers to signal, that would be really something.
Seriously, well done Arlington County.