- New efficiency tests see increases in Prius CO2 emissions
- Real-world economy won’t be adversely affected
- Read our full Toyota Prius hatchback review
Are the Toyota Prius and Prius+ now less economical?
In the real world there is no difference to how fuel efficient either a Prius or Prius+ is, compared with before. The change comes on paper, based upon a more rigorous testing protocol designed to more closely replicate the type of driving consumers experience day-to-day.
The Worldwide harmonised Light vehicle Testing Procedure (WLTP) will replace the existing New European Driving Cycle (NEDC) system that’s been in place for two decades.
Principally, WLTP is closer to how cars are driven out on the road and consequently the published figures will be much nearer to what’s actually achievable than NEDC ever was.
Manufacturers will publish both WLTP and NEDC figures from the second half of 2018, but for now – and somewhat confusingly – cars are being tested under the WLTP rules and converted to an NEDC-like result, rather than subjecting vehicles to the actual NEDC procedure.
Consequently, the results suggest cars tested under the WLTP system are less efficient – but in reality they aren’t.
Toyota is one of the first brands to switch to publishing the new figures, so expect 2018 to be a year of cars appearing to be thirstier with higher levels of CO2 pollution than before.
How do these changes affect Toyota Prius company car drivers?
If you already have a Toyota Prius or Prius+ then you’ve nothing to worry about – where it causes a problem is for those models sold from February 2018 onwards as they’re the ones based on the WLTP test results.
Previously a Prius hatchback on 15-inch wheels enjoyed a low CO2 figure of just 70g/km, placing it in the 13% Benefit-in-Kind (BIK) band for 2017/18.
Under the WLTP-based tests that’s jumped to 78g/km of CO2, equating to a leap to the 19% BIK band for 2018/19.
For an entry-level Prius Active that means a 20% rate payer who would have faced a monthly bill of just £52 will be forced to pay £76 for the same car from April 2018. That’s an extra £288 each year to the Treasury’s coffers.
Rubbing salt further into the wounds of those who regularly drive in the capital, the most efficient models will no longer be exempt from the London Congestion Charge as the ceiling is 75g/km of CO2.
The quoted average fuel consumption figure worsens to 83.1mpg, although expect this to be lower still when the official WLTP figure is quoted later in 2018. In reality the Prius is no less fuel efficient.
Priuses – or Prii according to Toyota – riding on 17-inch alloy wheels see an increase from 76g/km to 82g/km of CO2, moving them from the 17% BIK band for 2017/18 to 19% in 2018/19 – a more modest increase.
It’s a similar story for those looking at the Toyota Prius+ seven-seater, which, depending on wheel size, sees increases from 96-101g/km to 106-112g/km of CO2.
Is it bad news for the Toyota Prius Plug-in Hybrid too?
Yes and no. Although the plug-in version of the Prius has also seen a WLTP-related increase from 22g/km to 28g/km it still remains in the lowest BIK bracket (1-50g/km of CO2).
However, while that’s just 9% for 2017/18, it escalates to 13% for 2018/19.
For a 20% rate payer choosing the Business Edition Plus specification, that means a monthly rise from £47 to £69, or £264 more over the course of a year.
Nevertheless, the Toyota Prius family remains efficient compared with many other cars, the vast majority of which will also face WLTP-enforced tax increases over the course of 2018.