3006(b) of the Fixing America's Surface Transportation Act, shall not exceed total obligations of $10,150,348,462 in fiscal year 2020: Provided further , That the Federal share of the cost of activities carried out under 49 U.S.C. section 5312 shall not exceed 80 percent, except that if there is substantial public interest or benefit, the Secretary may approve a greater Federal share. Transit infrastructure grants For an additional amount for buses and bus facilities grants under section 5339 of title 49, United States Code, state of good repair grants under section 5337 of such title, formula grants for rural areas under section 5311 of such title, high density state apportionments under section 5340(d) of such title, and the bus testing facilities under sections 5312 and 5318 of such title, $560,000,000 to remain available until expended: Provided , That $390,000,000 shall be available for grants as authorized under section 5339 of such title, of which $195,000,000 shall be available for the buses and bus facilities formula grants as authorized under section 5339(a) of such title, and $195,000,000 shall be available for the buses and bus facilities competitive grants as authorized under section 5339(b) of such title: Provided further , That $40,000,000 shall be available for the low or no emission grants as authorized under section 5339(c) of such title: Provided further , That $40,000,000 shall be available for the state of good repair grants as authorized under section 5337 of such title: Provided further , That $40,000,000 shall be available for formula grants for rural areas as authorized under section 5311 of such title: Provided further , That $40,000,000 shall be available for the high density state apportionments as authorized under section 5340(d) of such title: Provided further, That notwithstanding section 5318(a) of such title, $3,000,000 shall be available for the operation and maintenance of bus testing facilities by institutions of higher education selected pursuant to section 5312(h) of such