And, I'll you another reason why. When the company is paying for it, I've taken a cab from Northern Virginia to BWI simply because it's much easier to leave the driving to a professional, while I enjoy the sites, talk on my cell phone, read the paper, or chat with the driver than it is to haul luggage to the metro, ride across town, transfer at Metro Center, get onto the Marc train at Union Station, then on a bus at BWI, and finnally to the check in counter. It costs me $70 with tip.