Trailer aerodynamics and glider kits might get a reprieve from the fuel-efficiency rules, but backing away from national rules would turn California loose, some warn.
Phase 2 GHG Rules to Curtail Use of Glider Kits
Starting in January of 2021, under the new greenhouse gas regulations, glider kits will be allowed mostly for their original purpose, which was reclaiming late-model powertrains from wrecked trucks.