To search someone’s home, police normally need to first get a search warrant. Vehicles, however, are treated differently. For a vehicle search to be legal, police only need to have probable cause that there’s incriminating evidence inside. This is often called the “automobile exception” to the warrant rule.

How then does a motorhome fit in? An RV is neither home nor car—it’s right in the middle. So which rule applies?

The U.S. Supreme Court answered this question in California v. Carney, 471 U.S. 386 (1985). In that case, DEA agents set up surveillance after receiving information that the defendant was using his motorhome to trade marijuana for sex. Agents watched the defendant approached a youth, who then accompanied him back to the motorhome. When the youth came out, the agents stopped and questioned him. He confirmed that he had received marijuana in exchange for giving defendant sexual favors. At the agents’ request, the youth went back to the RV and knocked on the door. The defendant stepped out, and—without a warrant or the defendant’s consent—agents entered the motorhome. Inside, they found marijuana. The defendant was charged with possession of marijuana for sale.

In court, the defendant argued that police violated his rights by searching his motorhome without a warrant. The government’s position was that police didn’t need a warrant because of the automobile exception.

The Supreme Court acknowledged that a motorhome was capable of functioning as a home, but nevertheless sided with the state. For the relevant purposes, the Court found that a motorhome is more similar to a car than a stationary house. The Court explained that, like with a car, a motorhome’s “ready mobility” makes it impractical for police to get a warrant before searching. And, according to the Court, a person doesn’t have the same compelling privacy interest in a motorhome that they would have in a regular home. These factors convinced the Court that the automobile exception should apply to motorhomes. The take away is that police need probable cause—but no warrant—to search a motorhome.