It’s almost two years ago now that we gave the century-old Autocar road test its last major facelift. Our 2024 re-jig was significant for changes in many parts, but none more significant than to the road test itself, which we adjusted so it had more to say about electric cars and PHEVs, more scrutiny in the way it tested them and more flexibility to address the relevant facets of any given new car.
One of the tests we added was an extra efficiency test schedule intended to give EVs and hybrids a fairer way to demonstrate one of their key strengths. We call it the ‘everyday’ economy test. Two years into its life, I thought now might be an interesting time to review which cars have excelled at it – and which have disappointed.
Before we added the ‘everyday’ bit, electrified cars had only the same efficiency tests that we habitually put all of our test subjects through as a way to show their potential. Those included a ‘track’ efficiency test schedule, showing the economy of a test car while actually being performance tested; a ‘touring’ test schedule done on the proving ground’s high-speed bowl for the sake of repeatability but designed to reproduce the economy returned on a 70mph motorway cruise; and an overall test average – what the test car returned over the entirety of its test loan with us, irrespective of type of usage.
None of these really gave electric cars or hybrids a fair chance, because the efficiency of EVs rises above others when they’re running at lower speeds (because they lose much less energy to waste heat than combustion-engined cars do) and when they have a chance to regenerate energy when slowing down.
The ‘everyday’ economy test, therefore, is made up of four concurrent laps of Horiba MIRA’s ‘Number Two’ circuit (in effect a 2.2-mile, two- or three-lane, equilateral triangle). These are taken at 10mph increments from 20-50mph, with two full stops per lap made for the test car to regenerate and redeploy energy.
As with all of the road test’s economy schedules, we depend on the car’s trip computer for the data we record. The trip is reset before every test, and the cars cover hundreds more miles away from the test track in the hands of our testers. That extraneous use gives us plenty of time to keep tabs on whether those trip computers are accounting accurately.
We’ve tested 55 new electric cars since that reinvented road test issue. Only one of them failed to post a better result in that ‘everyday’ test than it managed in the 70mph-typical, longer-distance ‘touring’ test, and given that was the 2013bhp Lotus Evija, we can consider it the exceptional outlier that proves the validity of the test.
To the cream of the crop, then. Nine of those cars posted a result of 5.0mpkWh or better. Some were the small, light kind of EVs you would expect to be capable of running efficiently – but one or two, not so much.
