The City of Seattle has achieved a 23% increase in miles driven per gallon and a 19% reduction in carbon dioxide emissions in its hybrid ambulance vehicles, exceeding the city’s expectations, XL Hybrids announced. Miles driven per gallon measures MPG while the vehicle is being driven and excludes idling time.

The company retrofitted two of the Seattle Fire Department’s Ford E-350 ambulances with its XL3 Hybrid Electric Drive System. With this recent success, the city is ordering up to 10 more vehicles this year, including Ford Transit vans equipped with the hybrid systems for the Seattle Department of Public Utilities.

The hybrid-electric ambulances have been used over tens of thousands of miles of driving on Seattle’s steeply graded urban streets and in fluctuating temperature. Used in 911 emergency response in Seattle’s city center, the XL Hybrids system has the same or better torque than stock ambulances, the company stated.

The ambulances are equipped with XL Hybrids’ cloud-based fleet vehicle connectivity and analytics system. It measures fuel efficiency, fuel savings, and carbon dioxide reduction, and provides access on smartphones and laptops for fleet managers to monitor their sustainability goals and cost savings.

The hybrid-electric technology requires no fueling infrastructure, no special plugs, nor extra driver training. The XL Hybrids system can be installed in hours and is compatible with new and existing Class 2 to 6 commercial fleet vehicles. The XL3 system installation leaves the original equipment manufacturer’s powertrain and warranty completely intact, according to the company.