To dream of a police van may represent a larger degree of discipline or control of a situation that is needed than is normal for you. Having to control or delay a large or intricate problem. Alternatively, it may reflect feelings about a large scale “round up” or controlling action by an authority figure.
Example: Jared Lee Loughner, currently serving a life sentence for attempting to murder a member of US Congress had a dream in his dream jounral that ended with a police van with a bed appearing and being driven away by him. this case may have reflected his need to temporarily stop all of his plans to kill Gabrielle Giffords months before he actually attempted to murder her.