Anyone who has watched police programs on television know search warrants. Judges issue these documents when a law enforcement officer is able to show the court that there is probable cause to believe that evidence of a crime may be found in some specific location. The idea behind warrants is to protect the privacy of people's property under the 4th amendment. However, it may be less commonly known by Pennsylvanians that warrants are not always used.
The legal requirements of a search warrant, including what can be used to show probable cause, and how specific the description of the place and what is being searched for needs to be, can be the subject of its own post. What Pennsylvania residents should realize, though, is that in many cases, police may conduct searches without obtaining warrants.
One way they do this is to plead "exigent circumstances." Because a warrantless search is usually presumed violated of the 4th amendment, law enforcement can overcome this presumption, if they show that certain factors made the search necessary for their safety, the safety of others, or to prevent the destruction of the evidence. In Pennsylvania, one type of warrantless search is now presumed to have exigent circumstances: the search of a person's vehicle. The state Supreme Court decided several years ago, in a drug charges case, to adopt the federal exception of motor vehicles from the warrant requirements of 4th amendment.
Of course, this does not mean police can randomly search any vehicle they like. They will still have to show that they had probable cause to believe a crime had been committed before searching, in order to avoid suppression of any evidence found. However, they do not have to take the time to apply for a formal warrant to conduct a search when they believe they have such probable cause. It should be remembered, however, that there are many way to attack alleged evidence in the criminal system and that defendants should consider the best ways to safeguard their constitutional rights.