Am I obligated or allowed to tell the police about a driver that texts or disobeys traffic rules while driving
The Minchas Yitzchok 8-148 discusses a very similar question. He says that a person that drives in a way dangerously such as speeding or driving in a wild way, that he would not be able to stop quick enough etc. endangers the public, and it is permitted to tell the police in order to protect the public. Texting while driving is very dangerous not only to the passengers in the car, but to and pedestrians or cars driving next to him. He does say however that one may only tell the police after the Bais Din warns him to stop driving in such a way.