"What is the Traffic Sign" is an educational iPhone application designed to help users learn about various traffic signs. The program covers a wide range of signs, including Regulatory, Warning, and Recreation signs. Users can study these signs using the provided simulations, all accessible offline without the need for an internet connection.

The app includes Regulatory signs such as Mandatory Stop, Give Preference, Forbidden Direction, No Turn Left, No Turn Right, No Return Left, No Return Right, No Parking, Regulated Parking, Prohibited Stop and Park, Forbidden to Overtake, and more. Additionally, Warning signs like Sharp Curves, Turns, Winding Tracks, Crossings, and more are also covered, offering a comprehensive learning experience.