10 CFR 431.428 - Effective dates of final rules.
(a) A final rule exempting a State standard from Federal preemption will be effective:
(2) Three years after such rule is published in the Federal Register; or
(3) Five years after such rule is published in the Federal Register if the Secretary determines that such additional time is necessary due to the burdens of retooling, redesign or distribution.
(b) A final rule withdrawing a rule exempting a State standard will be effective upon publication in the Federal Register.