The "Highways First Act" proposes significant changes to federal transportation funding by restricting the transfer of money between highway and transit projects. It amends title 23 of the United States Code to eliminate a provision that currently permits states to transfer up to 50% of certain highway funds to transit projects, effectively preventing such diversions. Additionally, the bill modifies title 49 of the United States Code by striking language that governs the transfer of funds between various federal transit programs. These amendments aim to ensure that funds designated for highways remain dedicated to highway infrastructure, limiting the flexibility of states and the Secretary of Transportation in reallocating these resources.