U.S. CPSC Compliance Requirements for Bicycles
US CPSC Compliance Requirements for Bicycles - This is just a summary of the CPSC's requirements. The full code is here.
One noteworthy exemption in the CPSC's requirements is that "one-of-a-kind bicycles made to order of an individual without assembling stock or production parts" are not regulated. That is to say that any custom made bike need not have, e.g., reflectors, brakes, etc.