SAN FRANCISCO -- BART is accepting the public's input on a proposal for a new discount for low-income adult riders that could begin as soon as fall of next year.Under the proposal being considered in partnership with the Metropolitan Transportation Commission, eligible riders would receive a 20 percent discount on all BART rides. To qualify for the discount, a rider's household income would need to be at or below 200 percent of federal poverty level guidelines. For a family of four, that would be an annual income of $50,200 or less, according to BART.The program would be funded through the MTC using gas tax dollars.Members of the public can complete anon the proposal through Dec. 31.