This SAE Recommended Practice provides standardized laboratory tests, test methods, and requirements applicable to many of the lighting devices and components covered by SAE Recommended Practices and Standards and is intended for reference for devices used on vehicles less than 2032 mm in width, regardless of length, or 7620 mm in length regardless of width. Tests for vehicles larger than 2032 mm in overall width are covered in J2139.
The vibration test in J575e which is referenced by FMVSS 108 was originally dated 1942 and revised through 1970. It refers to a SAE J577 Guideline, which was originally dated 1940 and revised through 1973. This old guideline contains an SAE vibration machine illustration and accompanying text "for a test machine which is satisfactory for the vibration test required by the SAE laboratory test specification and is published as a guide for building these machines." Design drawings for the SAE vibration machine shown in the illustration in SAE J577 exist at several automotive companies and are dated 1938.
Therefore, by 1938 it was determined that automotive vehicles needed a vibration test that was severe enough to ensure that lamps that passed the SAE Vibration Test (which required the use of the SAE Vibration Machine) would be strong enough to withstand the rigors of the interaction of the roads of 1940 (when the standard was approved) and the vehicle tire and suspension systems that existed in 1938 (when the SAE vibration machine was designed). Note, that in the 1939-1940 time frame the following did not exist:
a. advanced belted and radial tire designs using low air pressures, b. advanced hydraulic and gas shock absorbers, c. vehicle lamps that exceeded 7 inches in maximum width, d. an extensive local and secondary paved road system, e. an extensive interstate highway system, and f. electronically controlled and programmable vibration machines.
It should be clear that the many of the conditions that existed in 1939-1949 no longer exist and the goal of a vibration test to qualify lamps for passenger cars and light trucks should be to ensure that the lighting components used by these vehicles should "be strong enough to withstand the rigors of the interaction of the roads" that currently exist "and the vehicle tire and suspension systems" that currently exist (Note- a "test to qualify" is considered a qualification test of the minimum level of performance that is desirable).