Toyota's redesigned 2016 Prius features under-the-hood improvements that boost fuel economy and efficiency. Toyota has made extensive changes to the engine, hybrid drive system, and vehicle batteries that should improve EPA-estimated mpg by 10 percent on core models. The Eco model that will achieve an even greater improvement, according to the automaker.

The 2016 Prius is powered in part by a 1.8-liter VVT-i gasoline engine that has been re-engineered. The new engine achieves maximum thermal efficiency of 40 percent. This improvement was enabled in part through the use of a large-volume exhaust gas recirculation (EGR) system and improvements in combustion efficiency, according to a press release by Toyota.

Fuel efficiency is also boosted by improvements to heating performance. An active grille shutter has been added to open and close the grille, as necessary, in response to outside temperatures. The exhaust heat recirculation system has also been improved and made more compact.

Cold weather fuel efficiency has also been improved by introducing an engine coolant selector valve and adding a new system which accelerates engine heating.

The transaxle and motor have been redesigned, delivering a reduction in their combined weight. The motor itself is considerably more compact and gains a better power-to-weight ratio.

There is a 20 percent reduction in mechanical losses through friction compared to the previous model, according to Toyota. 

The use of a loss-reduction device in the power control unit cuts losses by about 20 percent. The unit can now be positioned directly above the transaxle.

The new Prius will be available with either a new lithium-ion or a new nickel-metal hydride hybrid battery. While the batteries use established technology, Toyota has increased their energy density, which means more power can be obtained from a smaller unit. This allows the battery to be relocated beneath the rear seat, increasing cargo space.

New updates to the hybrid system's software improve the feel of acceleration, giving a smooth and direct response in a lower rpm range. To improve brake feel and reduce noise, the all-new Prius utilizes a newly-developed active hydraulic booster for its regenerative brakes.

The new Prius will offer the Toyota Safety Sense P package that includes a pre-collision system with pedestrian detection. The system uses a millimeter-wave radar and a single-lens camera with integrated control to detect both cars and pedestrians. The package also comes with full-speed dynamic radar cruise control.

Drivers can also receive parking assistance with the intelligent parking assist, which uses ultrasonic sensors to detect surrounding objects and identify parking spaces.