Via GCC: http://www.greencarcongress.com/2016/09 ... prius.html
. . . Data gathered from more than 2,200 km (1,367 miles) of driving on a typical Rome commuting journey revealed that the test [4th gen] Prius cars spent an average 73.2% of the journey time (62.5% of the journey distance) producing no tailpipe emissions. These figures included periods when the car was stationary, with the engine automatically switched off.
The results were even better in urban areas . . . On these sections of the route, Prius achieved zero emissions for 79.4% of the journey time and 76.3% of the route distance.
Almost 45% of the car’s drive power was sourced from the electric motor, with 34.3% of its electric energy produced by the regenerative braking system.
The study project used a team of 20 drivers, evenly divided between men and women in age groups up to and over 35. There was an equal balance between those who had driven a hybrid car before, and those with no experience. Each participant drove the same 37 km (23-mile) route across Rome and back, at three different times of day—morning, afternoon and evening . . . For each journey the Eco drive mode was selected and the air conditioning was switched off; speed limits were observed at all times.