A vehicle may be impounded immediately without prior notice to the owner or operator thereof in the following cases which are found to constitute an emergency making prior notice to the owner or operator of the vehicle unreasonable and impracticable:
A. When any vehicle is left unattended upon any bridge, or upon any street or alley in such a way that it is obstructing traffic and the owner or person in charge of the vehicle is unable or refuses to remove it or provide for its removal.
B. Any vehicle that is left unattended upon any street or alley and is so parked illegally as to constitute a definite hazard or obstruction to the normal movement of traffic or emergency vehicles or which blocks or obstructs ingress or egress to a private driveway.