TX HB326

Authorizes annual automatic adjustment of Texas gasoline and diesel fuel tax rates on January 1 of each year based on changes in the "highway cost index," which tracks the 12-month moving average of materials and labor costs for state highway projects compiled by the Texas Department of Transportation

Requires the Comptroller to compute the new tax rates, publish them in the Texas Register, and notify all license holders by December 1 of each year

Applies the highway cost index adjustment mechanism to backup taxes imposed on persons who fraudulently claim off-highway use refunds, operate vehicles with untaxed fuel, or acquire fuel through unlawful means

Updates the fee calculation for certain diesel fuel uses under the Transportation Code to reference the new variable tax rate provisions

Takes effect September 1, 2025, with the initial adjusted tax rates computed by December 1, 2025, and becoming effective January 1, 2026