Metro Phoenix celebrated the opening of the Central Phoenix/East Valley Light Rail Transit Line in December 2008, after four years of construction. The $1.4 billion, 20-mile line is the first paved or embedded track installed in Arizona. The program will extend to 37 additional miles by 2025. The system uses a predictive priority traffic signal system, which continuously adjusts the timing of lights in intersections where trains pass through so motorists are not impeded.