UPS has expanded its fleet of alternative-fuel vehicles with the deployment of 50 next-generation hybrid electric delivery trucks.

The 50 hybrid electric vehicles will operate in Atlanta, Dallas, Houston and Phoenix.

The 50 new HEV package cars are expected to reduce fuel consumption by roughly 44,000 gallons over the course of a year compared to an equivalent number of traditional diesel trucks.

The HEV fleet will feature two different size vehicles from Workhorse Custom Chassis and Freightliner LLC and a hybrid power system from Eaton Corporation.

UPS isn’t the only package delivery company greening its fleet – Fedex, for one, is adding similar vehicles to its fleet.