I have relatives in the Washington, DC suburbs. They park in the station parking garage and meet me at the information desk which is near the garage entrance. However, I try to avoid arriving during the horrendous rush hour traffic . DC area traffic is the worst I have experienced. I once took two hours to drive a rental car from WUS to Arlington, VA, across the river. I now use the Metro to go to the suburbs and make it easier on my relatives to pick me up.
There is a large roundabout in front of the station. With cell phone coordination you could be picked up somewhere on the circle, but there is no designated wait parking.