Originally Posted by
aresef
Other tip: Park at a light rail station (Timonium if you're coming from the north, Linthicum or BWI Business District if south). Parking is free -- nobody really minds if you park there and nobody is really going to bother you, if you're just gone a few days. Just pay the $1.60 each way. And remember to lock up. The train will drop you within spitting distance of the international terminal.
If I recall the small parking lot at the BWI Business District station has clearly posted signs that say "No Parking 1 am - 5 am".