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I'm curious if anyone knows if its safe to travel MARTA.
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It's not really a matter of safety so much as uselessness. MARTA is the only metro rail system that doesn't seem to go anywhere - just from one ghetto to another. Every other rail system I've used in the US, even the little one in Los Angeles, has been pretty good. MARTA is just a jobs program.
It's good for going to the airport, if you don't have to haul a bunch of luggage. I use it to go to the Dome sometimes too.