Public laws are codified by subject in the U.S. Code
Private laws are not codified. Statutes at large in the only publication they are in.
Bills (and resolutions) are the usual form in which legislation is proposed. More than 85% of bills introduced are never passed; they "die in committee."
Bills prior to 1989 (101st Congress) that were never passed can be difficult to locate. Bills are often reprinted in hearings; Senate bills are sometimes printed in the Congressional Record. Bill summaries can be useful when the text of the bill cannot be found.
See the Research Guide: U.S. Government Legal Information (Statutory Law) for information about bills that have been signed into law.
H.R.6536 - No School Bus Drivers with DUIs Act of 2016, 114th Congress (2015-2016). (congress.gov)
Bills are often reprinted in hearings; Senate bills are sometimes printed in the Congressional Record.