Forced Blood Draws Require A Warrant
The US Supreme Court ruled that police officers are generally required to get a warrant when they can reasonably do so before they can draw blood when a DUI / Drunk Driver refuses to provide a breath or blood sample. People have a protected privacy interest in preventing a government agent from piercing their skin. Up until now in California, when people refuse to give a breath/blood sample, the police were threatening to physically restrain or physically restraining people and drawing their blood.
In an 8-1 decision, the Supreme Court affirmed the 4th Amendment of the Constitution protects motorists from a warrantless intrusion into the the skin of people. Getting a warrant can easily be done over the phone or by fax in a relatively quick manner.
It remains to be seen if police will actually take the time to get a warrant.