Shortly after entering Logan Airport, the road forks with the right fork labeled "Departures", and the left fork labeled "Arrivals". So if it's 5 AM and you are driving to Logan to depart on a flight to Seattle that leaves from Terminal A, which one do you choose? It's obviously a trick question since choosing "Departures" will bring you to the upper level of Terminal A where cabs and buses drop off passengers, and "Arrivals" will bring you to the lower level of Terminal A, where cabs and buses pick up passengers. The right answer is: neither. Instead you need to follow the signs for "Central Parking", park, then walk over to Terminal A.
Just as you wouldn't assign three possible values to a boolean, Logan shouldn't try to impart three possible choices in two signs. What about this crazy idea: Dropoff, Pickup and Park.