Traffic signals are an elementary component of all urban road networks and play a critical role in controlling the flow of vehicles. However, current road transportation systems and traffic signal implementations are very inefficient. The objective of this research is to evaluate optimal phase ordering within a signal cycles to minimize the average waiting delay and thus in turn minimizing fuel consumption and greenhouse gas (GHG) emissions. Through extensive simulation analysis, we show that by choosing optimal phase ordering, the stopped delay can be reduced by 40% per car at each signal resulting in a saving of up to 100 gallons of fuel per traffic signal each day.