The seminal case on the subject is Welsh, a US Supreme Court case that ruled a search of a home for a DUI driver was illegal. In Welsh v. Wisconsin (1984) 466 US 740, the US Supreme Court ruled that the Fourth Amendment was violated when an officer made a warrantless entry into a residence to arrest a DUI suspect. Apparently though is Wisconsin the law treats DUI as a ticket which carries only a fine as punishment. Unlike Wisconsin, California treats DUI as a criminal offense, subject to fines and mandatory incarceration. This distinction was relied on by the California Supreme Court to find that a warrantless entry to arrest a recent DUI suspect did not violate the Fourth Amendment.
There have been more recent California cases which allow warrantless entry in a home for DWI suspects. We will discuss these cases and the current legal trends in future articles.
Matthew Ruff is a DUI Lawyer in California, he can be reached at 310-527-4100