After review of the request for modification, the Associate Administrator may seek further information either from the manufacturer or through a notice published in the FEDERAL REGISTER requesting comment on whether a modified light source incorporating the changes requested will create a noncompliance with Federal Motor Vehicle Safety Standard No. 108 when substituted for an unmodified light source. If the Associate Administrator seeks public comment on a submission (s)he shall publish a notice stating whether (s)he has accepted or rejected the submission. If a submission is accepted, the Associate Administrator files the information in Docket No. NHTSA 98-3397. If a submission is rejected, a manufacturer may submit information with respect to it, as provides in paragraph 564.5(a), for consideration as a new light source after such changes as will insure that it is not interchangeable with the light source for which modification was originally requested.
49 C.F.R. §564.5