The Prius Plug-in is the most advanced member of the Prius Family yet. Combining an extended all-electric mode  with proven hybrid technology, it can get you up to 475 miles before your next fill-up, depending on driving conditions.  You also get the convenience of plug-in charging with rapid recharge times
The idea of battery-powered cars is cool. But in reality, the weight, size, cost and durability of the large-capacity batteries required to fully power Electric Vehicles (EV) are critical issues that aren't fully solved. Our answer? Small lithium-ion battery packs that complement the proven Prius hybrid-electric power train.
The Prius Plug-in's lithium-ion battery is lightweight and compact, weighing a total of just 330 lb. So you get useful EV power and driving range without the costs of an electric-only EV battery, while maintaining plenty of cargo space and seating for five. Also, charge time from a standard 120V household outlet is only 3 hours.
Built to last for the life of the vehicle, our lithium-ion batteries have undergone more than three years of coordinated field testing in Japan, North America and Europe, in a wide variety of climatic environments and driving conditions.
The Prius Plug-in's 4-cylinder engine is incredibly fuel-efficient. The first reason for this is its 1.8L displacement, which allows it to generate higher output and torque while operating at lower speeds. In addition to increased efficiency, you also get a much quieter ride. Another factor is the elimination of the drive belt, along with an electric-driven water pump, which reduces supplemental engine load. This allows the engine to control the flow of coolant with increased precision based on vehicle conditions.
The electric motor in the Prius Plug-in is specially calibrated to give you greater fuel efficiency across a variety of driving conditions. And since it operates at an incredibly high rotational speed, it's able to generate more output in a smaller, lighter design—which also helps improve your overall fuel economy.
 Prius Plug-in EV mode works under certain conditions up to near freeway speeds for approximately 10-15 miles on a full charge. Sudden acceleration or climate control usage may prevent EV mode usage.
 CAUTION! When driving a hybrid vehicle, pay special attention to the area around the vehicle. Because there is little vehicle noise in electric-only mode, pedestrians, people riding bicycles or other people and vehicles in the area may not be aware of the vehicle starting off or approaching them, so take extra care while driving.
 Based on preliminary combined 50-mpg estimates determined by Toyota and 9.54 gallons of gas. EPA estimates not available at time of posting. Actual mileage will vary. Actual topography and road conditions are not taken into account.
LAcarGUY sneak preview of the 2012 Toyota Prius Plug-in Hybrid