How about a 1947 Plymouth, deployed as an LAPD patrol car, like this one?
In 1947, the Adventures of Philip Marlowe, starring Van Heflin came to Radio in the Summer of 1947 as a Pepsodent Program replacement for their wildly popular show starring Bob Hope. Said Heflin of his immersion into the role:
We rode in the back seat of Radio Car 11-A, operated by two pleasant young policemen, John Breisingher, who drove, and Bill Lesner, who kept a log of our maneuvers.
"Car Eleven-A," the voice of a woman dispatcher droned over the dashboard radio. That was us!--and sharp-chinned, curly-haired Van (and I) sat forward eagerly. "In the 200 block on East Seventh Street--merchandise on sidewalk." That seemed a curious complaint.
At the address, two men were pushing electric stoves and refrigerators into a store. Officer Lesner verified that they were the owners, not burglars. We drove into the river bed to look for vagrants. The officers arrested a drunk who turned out to be an ex-convict. We broke up a beer joint quarrel--one man claimed another had robbed him. We went through a second-floor flophouse (beds, 25 cents) where the air reeked, a drunk lay on the corridor floor. The stooped and nearly toothless proprietor complained that a nearby rescue mission was keeping his 310 tenants awake with their hymns, piano, and drum. Officer Bresingher exacted a promise form the revivalists to recess activities henceforth at 9 p.m.
Van's earnest comment was: "I don't see how this could ever get monotonous!"