通常不可以检查，但是检查了也不违法。
A police officer is normally not allowed to search your vehicle. However, there are several exceptions to this. An officer who observes you trying to either hide something under the seat or throw something out the window may legally search your car. Once cops are on your rear bumper with his spotlight silhouetting your every move, they're watching for any sort of furtive movement. A sudden lowering of one or both shoulders will tip them off that you're attempting to hide something under the seat.
If the officer has a reasonable suspicion you are armed and dangerous, he or she can frisk you (pat you down). Similarly, if the officer reasonably suspects that you are involved in criminal activity he or she can also perform a pat down, and if police officers have probable cause -- a reasonable basis or justification to believe that you or your passengers are involved in criminal activity -- they can search your car and objects belonging to passengers.
