You’re not allowed to text and drive, but you may be wondering how the police would even know what was happening. It’s not as if you hold your phone up for all to see. How do they spot drivers who are texting behind the wheel?

There are a few different tactics. For instance, the police in New York often choose to ride in tall SUVs specifically because it gives them a better view of what is happening in a car in another lane. Even if you have your phone in your lap, they can still see it from that vantage point. This is similar to how semi-truck drivers often have a clear view of what is happening in the cars around them.

Of course, the police can also look for signs that indicate that you may have been texting, just as they look for signs that someone may have been drinking. If you don’t start driving when a stoplight turns green, for instance, they may assume that you are on your phone. If you drift over the center yellow line, they may assume you weren’t watching the road because you were watching your phone.

Is it a perfect science? Of course not. Maybe you were just turning up the radio. Maybe your car has a mechanical problem. The police cannot know for sure if you were texting, but that may be enough for them to initiate a traffic stop to find out.

If you end up getting a ticket, it’s important to know exactly what options you have and what legal steps to take to defend yourself.