The main purpose of this legislation is to amend existing laws regarding the distribution of federal funding for public transit. Specifically, it aims to create a new funding formula that allocates resources to medium-sized cities that have a high level of transit use. This is intended to support urban areas with populations between 200,000 and 999,999 that are performing well in certain transit metrics. Key provisions of the legislation include the establishment of a formula for how funds are distributed to eligible cities.