In Australia, a zed-car is a cars belonging to the Commonwealth (i.e., federal national) government, because the vehicle registration plates begins with a Z.

Z-car is a Nissan sports car

Z-Cars is a British 1960's and 1970's television series

Panda car

Honda Z

Jam sandwich (slang)

"Z-car" was sometimes used in 1960's and 1970's British newspaper headlines to mean any police car

In Cyprus, a zed car is a hire car, because its registration plate begins with a Z.