http://www.dart.org/fares/tvminformation...
http://www.mbta.com/fares_and_passes/cha...
http://www.bart.gov/tickets/sales/machin...
Some parking lots machines accept $20 as well.
A 2010 announcement of $20 support for one bill handler
http://www.meigroup.com/global/news_events/mei_industry_news/conlux_bill_validator_now_1/index.xml
A new Canadian Polymer $20 has caused havoc with vending machines
http://www.cbc.ca/news/canada/ottawa/new-polymer-20-bills-a-vending-machine-headache-1.1343770
They can, if the operator set them up to. The bill acceptors have setting that can be changed. I can make my machines take $2 bills if I want. Most machines that do take $20 bills will give you back dollar coins.
too much different kinds of change would be needed so probably not - very few even take $5 bills
some can it depends on the machine. usually it say if they can or not
No, because they can not stock the change it would require.
