[Code of Federal Regulations] [Title 49, Volume 6] [Revised as of October 1, 2006] From the U.S. Government Printing Office via GPO Access [CITE: 49CFR555.15] [Page 161] TITLE 49--TRANSPORTATION CHAPTER V--NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PART 555_TEMPORARY EXEMPTION FROM MOTOR VEHICLE SAFETY AND BUMPER STANDARDS--Table of Contents Subpart B_Vehicles Built in Two or More Stages and Altered Vehicles Sec. 555.15 Time period for exemptions. Subject to Sec. 555.16, each temporary exemption granted by the Administrator under this subpart shall be in effect for a period of three years from the effective date. The Administrator shall identify each exemption by a unique number.