Here is the 21 April 2009 Supreme Court decision in Arizona v. Gant. Basically it limits the scope of a warrantless car search. In the course of its decision the court did not overrule New York v. Belton, 453 U. S. 454 (1981), but concluded Belton was misunderstood and misapplied.
This was a 5 – 4 Decision.
Here is a “news release” by the FLETC legal staff. This is what all U. S. law enforcement personnel currently attending FLETC or who get their alerts is being told about the impact of Arizona v. Gant. All CID/OSI/NCIS/CGIS agents claim to have attended FLETC. So, they are on notice and the “notice” gives you some ideas on investigative and cross-examination questions of the police if your search involves a warrantless search of an auto.