As a general rule, the rear car is always said to be at fault when hitting the back end of another vehicle. The idea is that every driver is supposed to leave enough space ahead of them that they can stop in an emergency. This is known as a safe following distance.

There are exceptions to this rule, but it usually holds up. The key, then, is to understand what a safe following distance really looks like. A lot of people underestimate how much space they need.

One way to figure it out is to leave three seconds between cars. To do this, just wait for the car ahead of you to pass a fixed object, like a road sign. Then count off seconds until you pass it. If it does not take you three seconds to get there, you’re too close.

You may have heard of this referred to as the two-second rule. In some cases, two seconds may work, but the issue is reaction time. For some people, it takes nearly two seconds just to react, and so there is a delay between the need for a stop and the person actually pressing down on the brakes. Therefore, they say that a bare minimum is two seconds. It may work, but it’s safer to give yourself three seconds instead, ensuring that you have enough distance and enough time.

Even if you do this, the driver behind you may not. If you get injured in an accident as a result, you may need to seek out financial compensation for your medical bills and other costs.