US regulations for bicycles offered at retail to consumers:

https://www.ecfr.gov/current/title-1...er-C/part-1512

The pedal reflector section:

https://www.ecfr.gov/current/title-1...12#p-1512.16(e)

Note: these federal regulations for new retail sales can be and probably are different from the various states' requirements for legal use on roadways.