Abstract: A method and apparatus for a navigation system is designed to avoid traffic rule violation. The method includes the steps of: evaluating requirements prescribed by local carpool lane regulation for using a carpool lane of a road; determining a number of occupants of a vehicle; determining whether the number of occupants of the vehicle satisfies the requirements; detecting a current location of the vehicle as to which lane the vehicle is running; detecting a lane change action for the carpool lane indicating that the vehicle enters the carpool lane or about to enter the carpool lane; and generating a warning for notifying violation of carpool lane regulation when the lane change action for the carpool lane is detected and the number of occupants fails to satisfy the requirements.