They are buried in the "Code of Federal Regulations" (CFR). This is what makes them so hard to comply with. There may be a dozen regulations within the regulations put out by the EPA concerning things like exhaust requirements, allowable gases to use in air conditioning systems and so on. Then others relating to, say, crash worthiness somewhere else under a different department like the Transportation Safety Department. As a result finding all of the regulations pertaining to manufacturing a car requires searching the millions of Federal Regulations which in turn requires an army of lawyers. Then once you've found all of the regulations that pertain to car manufacturing you would need another army of engineers, both design and test, to prove to the government that you are in compliance with them.