Synchro (AKA: Synchro Studio) is a famous traffic signal coordinating and timing design software developed by Trafficware. It was developed according to the standard HCM (Highway Capacity Manual) specification of US Department of Transportation. The parameters in this standard are set according to the performance of vehicle, driver's behavior habits, traffic regulations, and so forth. Some results obtained by using it (such as delay time, service level, exhaust emission, etc.) have important reference value as relative parameters for schemes comparison, and its signal timing is very reasonable.