In plain terms. CAR is the Department of Commerce's supplement to the FAR, adding Commerce-specific acquisition rules.
Who it applies to. Contractors serving Commerce bureaus (such as NIST, NOAA, the Census Bureau).
What it requires. Follow the FAR, then CAR additions. Commerce holds sensitive economic, census, and research data, so expect information-security and data-handling terms; note that NIST — whose standards drive federal cyber rules — sits within Commerce.
Why it matters. Commerce stewards sensitive statistical and research data, and its NIST bureau authors the very standards contracts rely on.
Citation. CAR, the Commerce Acquisition Regulation supplement to the Federal Acquisition Regulation (FAR), codified in the FAR System at Title 48 of the C.F.R.