Hybrids drive solely on electric power for more than 60pc of the time they are on the road, a new Irish university study reveals.
The research by UCD academics also shows that, even over long journeys, hybrids manage to travel more than half the time without the engine running.
Hybrids are often perceived to be at their best in urban driving – and at their worst on longer journeys.
The UCD study found that overall, and including long-distance commutes, the Toyota Prius hybrids were in zero emissions mode (ZEV) for 62pc of the time and more than 40pc of the distance covered. ZEV is when the engine is not running.
The research measured seven drivers during their normal weekly routes – they racked up 2,000km between them in the Prius models.
In city centre commuting, the hybrids were in zero emissions mode for 75pc of the time and drove more than half the distance on electric/battery power.
The three drivers with the longest commutes had the best fuel economy (almost 60mpg).
The study, published today, was commissioned by Toyota Ireland. Research was conducted through ConsultUCD and authored by professors Robert Shorten and Giovanni Russo, UCD School of Electrical and Electronic Engineering, Prof Francesco Pilla, UCD School of Architecture, Planning and Environmental Planning, and Prof David Timoney, UCD School of Mechanical and Materials Engineering.
Their research tracked seven drivers who commuted to UCD, Belfield from Drogheda, Wicklow, Aughrim, Smithfield, Blackrock and Dundrum (2) over a full week last November. The commute was in addition to normal family driving.
Their conclusions are based on analysis of more than 2,000km of typical motorway, rural-road and city-route driving.
The researchers measured the time the cars spent in zero emissions versus engine-running modes. No guidelines were given to the drivers.
Prof Timoney said: “Highlights of the study include a high percentage of zero-emissions driving recorded across a wide range of conditions.
“Also noteworthy is the close agreement of the measured fuel economy with the official Worldwide Harmonised Light Vehicle Test Procedure figure.”
Toyota corporate affairs director Mark Teevan said: “This is the first study of this type carried out in Ireland and we anticipate its results would be replicated across the country.”
The study also showed that for the journey from Smithfield to UCD, the hybrid was in zero emissions mode three-quarters (76pc) of the time and for more than half (57pc) the distance. Drivers from Dundrum and Blackrock were in zero emissions for two-thirds (64-67pc) of the time.
Those commuting from Drogheda, Aughrim and Wicklow town spent 56pc in ZEV over the respective 644km, 452km and 293km driven during the week.
Average consumption was 4.92 litres/100km (57mpg). Average C02 emissions were 114.2grammes/km. The three drivers with the longest commutes averaged almost 60mpg.
In conclusion the report’s authors say: “The study was funded and commissioned by Toyota Ireland.
“A key methodological diﬀerence with a previous Toyota study in Rome is that the present study is based on commuting behaviour of a population of seven UCD employees, rather than a single vehicle traversing a predetermined route.
“The total aggregated distance was 2,018km accumulated over 157 trips.
“Overall, it was found that, on average, the car was in ZEV mode for 62pc of the commuting time and for 40.4pc of the average commuting distance.”