The numbers are here [1]. BART generates about $300M in revenue and gets $500M in "financial assistance," of which $320M is sales tax revenue.
[1] https://www.bart.gov/sites/default/files/2025-09/FY26%20Adop...
[1] https://www.bart.gov/sites/default/files/2025-09/FY26%20Adop...
BART taxes are not even in the top 100 list of expenses I worry about personally.