If driving a Toyota hybrid system isn’t good enough for you, a new research shows that the already fuel-efficient and environmentally friendly Prius just got that much better with the fourth generation.

The University of Rome gather 20 drivers, evenly divided between men and women of various age groups up 35 years old, and took them on a 37-kilometer drive across and back at three different times of the day – morning, afternoon and evening – to determine the overall performance of the all-new Prius.

After more than 2,200 kilometers of driving, the Prius spent an average of 73.2-percent of the time travelling without any tailpipe emissions. This includes moments when the vehicle was stationary and with the engine switched off.

Testing the all-new Prius' emissions during city driving

Those numbers were even better in the urban sections of the drive where researchers were trying to determine if the stress on the drivers and on the vehicles might change the performance of the Prius. In contrast, it achieved zero emissions 79.4-percent of the drive in the city.

For full disclosure, the Eco drive mode was selected all throughout the drive and the climate control was switched off as well.

Toyota’s latest Hybrid Synergy Drive powertrain allows the vehicle to derive 45-percent of its power from the electric motor that gets 34.3-percent of its energy from regenerative braking.

The all-new Toyota Prius is set for launch at the upcoming 2016 Philippine International Motorshow (PIMS).