Identifying police and fire trucks enforcing car safety is not always simple. In most states, only police cars use blue lights while fire trucks use red lights. But in certain states, the opposite is true. Double-check your local laws in our handy table.

There’s much more to the laws dictating emergency vehicle lights than their color. Certain states regulate when police or fire vehicles can use their lights or where they can place them.

For example, many states require fire trucks use red lights and police to use blue lights. But certain states also allow a non-flashing blue light at the back of a fire truck, to make it more visible in the daylight. If you think blue lights always mean police in these states, think again.

Our source for the above table is Extreme Tactical Dynamics. This website maintains a database of the current emergency vehicle light laws in every country.

Like the laws around emergency light colors, the laws around unmarked police cars vary by state. States that do allow traffic stops with unmarked police cars require that those cars have light bars. But those lights can be hidden behind the grille or inside the cab of the car.

Not only do unmarked police car laws vary by state, but several states have recently changed their laws or best practices. Make certain to check out our state-by-state guide to unmarked police cars or find out why the color of police car lights varies by state in the video below.

How to Spot Unmarked Police Cars (With Pictures)