This bill, known as the "Highway Formula Fairness Act," revises the method for calculating federal highway program apportionments for states, effective fiscal year 2027 and beyond. It amends Section 104 of title 23, United States Code, to establish a new formula for distributing funds across several key programs. The initial amount for each state will be determined by its proportion of combined apportionments received in fiscal year 2012 compared to all states. Following this initial calculation, the bill mandates an adjustment to ensure that each state's combined apportionment is not less than 95 percent of an "applicable percentage" of the total available funds. This applicable percentage is derived from the ratio of estimated highway user tax payments from that state into the Highway Trust Fund (excluding the Mass Transit Account) to the total payments from all states for the most recent fiscal year. This mechanism aims to ensure states receive a minimum return on their contributions to the federal highway system.