Police chases are commonly found in open-world games. In these games, the player can trigger a police chase at any time. He can do this by catching the attention of police by comitting crimes, such as running over somebody in front of the police. The police will then begin the chase.
In order to escape, the player must lose the cops. He can do this by remaining unseen by police for a certain amount of time, escaping a certain area or killing any police who might be following him. Higher levels of notoriety can make it more difficult to escape.
When the player is the one doing the chasing, he usually has to destroy the car he's chasing, often achieved by shooting or ramming it.