When an engine idles, fuel economy drops to zero. Most light-duty and medium-duty work truck engines burn between 0.6 and 1.2 gallons of fuel per hour when idling. Reducing idling can significantly reduce wasted fuel — and with fuel prices ringing in at around $6 per gallon, the associated savings can add up quickly. WorkTruck Online magazine goes more into detail the technology behind Xantrex and ZeroRPM that helps fleets reduce the impact and costs of idling on job sites.