BART is a good system, competently run. Would be better if it ran 24/7; as it is, it shuts down shortly after midnight, which makes it impractical for late-night recreational travel.
However nothing beats the NYC subway system, with a station within a few blocks of anywhere, and 24/7 service. I've never felt unsafe on the system even at 3:00AM with one or the other end of the trip in a slightly sketchy part of town.
The problem with urban light rail systems, of course, is crime, particularly in the late hours. The solution to this is to have video cameras in the cars, and seating areas that are marked off as being directly in the best view of the cameras, and signs reminding the passengers that the police are watching these cameras live all the time.
Stations also need to have public WCs that are fully operational, safe, and private. News-stand concessionaires could be put in charge of monitoring these to be sure people don't leave them a foul mess, and people who do so should be arrested and thrown in the tank overnight.
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Re. the other topic: I wash my hands before leaving every customer's site, and upon getting home each night (as well as the usual routine after using the toilet and before eating).
What I would do about doctors who don't wash hands after using the toilet: put up a sign in the loo (printed in a suitable font, e.g. Helvetica Bold) saying "If you don't wash your hands after you pee or poop, someone nearby will remind you in a sufficiently loud voice that you will be seriously embarrassed. We don't want your fecal coliforms, thank you. And don't say you weren't warned."