IL HB4399

Amends the Illinois Vehicle Code to require diesel-powered vehicles owned by state government, counties, local governments, school districts, community colleges, public universities, and mass transit agencies to use 19% biodiesel blend beginning July 1, 2027

Increases the current biodiesel requirement from 5% to 19% for public fleet vehicles

Allows a reduced biodiesel blend of at least 10% during winter months (December, January, February, and March)

Exempts vehicles with engines designed or retrofitted to operate on higher biodiesel percentages or ultra low sulfur fuel

Takes effect immediately upon becoming law