Typical auto trips are within the driving range of efficient electric vehicles (EVs), but typical vehicle use also includes occasional trips that exceed EV range. EV users may face the necessity of maintaining a second car, or renting a car, for such trips. An alternative is the use of a range extending trailer (RXT), a trailer-mounted generator that, when towed behind an EV, effectively converts the EV to series-hybrid mode for long trips.AC Propulsion Inc., with funding support from the South Coast Air Quality Management District (SCAQMD), has developed an RXT to evaluate commercial prospects for this concept. It incorporates a high specific output gasoline-fueled generator-set, engine and fuel controls for low emissions, and self-contained steering control to improve maneuverability. (See Appendix for RXT specifications). Successful series-hybrid operation is demonstrated. Emissions and fuel consumption from RXT operation are quantified.