Owners find most EVs offer significantly less range than advertised at highway speeds.
The EPA only tests cars up to 60 mph in its range estimates.
Tesla vehicles are among the worst offenders while the Porsche Taycan is actually better than advertised.
Many new owners of electric vehicles are finding out that their car’s real-world range is actually significantly lower than the EPA and the manufacturer advertises, especially on the highway.
It is no secret that official fuel economy figures have always been a portrait of the “best-case scenario” rather than an actual picture of what owners can expect and this seems to have carried to the electric era.
Indeed, the range figures put forward by automakers and the EPA don’t account for high-speed highway driving, the setting in which EVs are the least efficient.
This is because the EPA only tests vehicles at a maximum speed of 60 mph (96 km/h) while 19 states in the U.S. have speed limits of 75 mph (121 km/h) or higher and many Canadian provinces allow driving up to 110 km/h.
Furthermore, the EPA gives more weight to city efficiency in its ratings, which artificially inflates the official range figures for drivers who cover long distances on the highway.
Indeed, driving at 75 mph (121 km/h) could cut range by 38% when compared to driving at a steady 55 mph (89 km/h) according to Lennon Rodgers, an engineering professor at the University of Wisconsin.
This means that without accounting for hills, traffic, acceleration, or temperature, an electric vehicle that has a range of 450 kilometres at 55 mph would only be able to drive 279 kilometres at 75 mph.
This means that even with the longer ranges seen in new models launched over the past year or two, many drivers who frequently make long highway trips are better off with a plug-in hybrid model since they benefit from emission-free driving in town and don’t need to stop for a charge.
The discrepancy in advertised versus real-world range is obviously not the same for every vehicle, which is why Tesla models tend to lose around 10 to 12% of their range on the highway while the Porsche Taycan actually performs better than advertised even in this unfavourable situation.
This is interesting but not surprising since our previous tests of the Taycan showed that its EPA range estimate is deceptively low.
According to the EPA itself, range estimates shouldn’t be taken as an exact figure but rather as a way to compare different electric vehicles on the market.
A study by J.D. Power recently showed that EV drivers are more satisfied with a vehicle that can consistently achieve a somewhat lower range rather than one which overpromises and under-delivers.
This means that changing testing methods to better reflect real-world situations could have a more positive impact on satisfaction than simply increasing the advertised range with each new model.