This is a short survey about freeway ramp meters in the Phoenix metro area. 

A ramp meter is a device that regulates the flow of traffic entering a freeway. Ramp meters are located at most freeway on-ramps in the Phoenix metro area and are only active at certain times of the day. A ramp meter has two alternating red and green lights and looks similar to a traffic signal. 

The Arizona Department of Transportation has begun testing whether adjusted timing of ramp meters can improve traffic congestion on State Route 51 (Piestewa Freeway). Please help ADOT by taking this brief survey about ramp meters and sharing your thoughts on the SR 51 test.