The scene is a staple of cop movies: the hero police officer is in hot pursuit when the suspect slips aboard a bus or into a taxi. The desperate officer stops the nearest driver, presents his badge, and tells the civilian, “Police business, I need your car!” While the scene is common in movies, it almost never happens in real life. But it’s possible. Experts are unsure whether it would be illegal for you to refuse.

When a “Street Smart” column in the Los Angeles Times asked whether any police had done it, a retired street cop named Dennis Zine admitted that he commandeered vehicles three times in his career. One private delivery truck, one city-owned garbage truck, and one bicycle. He also admitted that he was in the vast minority of cops; this almost never happens.

Now I want to watch a chase in which the police officer is driving a commandeered garbage truck.

Zine’s experience grabbing a passerby’s bicycle to use in a chase illustrates why police officers will use every other available option before commandeering a civilian vehicle. No sooner had the cop jumped astride the bike and pedaled off after his suspect, than he discovered the brakes didn’t work.

The Los Angeles Times also quoted FBI Agent Steve Kodak saying, “The reason you wouldn’t do it is the liability issues. The legal liabilities would be so large.” 

So can you tell a police officer, “No” if they ask for your car? That’s a tricky one. The law varies from state to state. David Mikkelson, the founder of the Snopes fact-checking website, reveals that in California, refusing the demand would likely fall under an old federal law called posse comitatus. This remnant of the Wild West states that when police declare a “posse comitatus” or “power of the county,” any able-bodied adult who refuses to help can be fined up to $1,000.

Does posse comitatus apply to your possessions? Maybe. But there’s no legal precedent. As far as Mikkelson knows, no one’s ever been successfully charged and fined for refusing to turn over their car.

What do you do if an officer asks for your vehicle? For starters, at least warn them if it has no brakes.

So if this is a very rare occurrence in real life, why is it so common in movies? Perhaps it just makes chase scenes more interesting if the hero is, say, driving a garbage truck. But my theory is that it’s an easy way to put the latest, greatest cars on screen for some product placement.