Over time, sensors connected to counters will tell a tale of how popular the 18.1-mile bike and walking path has become.
July 31, 2013 A view of the Mount Vernon Trail in Alexandria. As travelers bike, run and walk the 40-year-old, 18.1-mile path, they unknowingly trip a series of sensors. Those sensors are connected to counters, which over time will tell a tale of who is using the route and when. Matt McClain/The Washington Post Buy Photo