In our testing of EPA projections, EVs did much worse than gas-powered cars, according to a recent study co-written by Car and Driver’s testing head, Dave VanderWerp. The analysis compares real-world highway test results to EPA fuel economy and range estimates. It finds that, on average, EVs don’t meet the EPA’s range predictions. The authors suggest that the problem can be fixed by standardizing testing methods and putting information about city and highway ranges on the price tags of new cars. A recent SAE International study found that internal-combustion cars perform better than electric vehicles in real-world efficiency and range compared to EPA projections by a much larger margin than statistics from Car & Driver’s real-world highway tests. EVs usually have a field much shorter than what is written on the window label, even though they often meet or beat the EPA’s expected highway fuel economy numbers. This week, the study was shown at the yearly WCX conference by SAE International. It was made by Dave VanderWerp, who is in charge of testing for Car and Driver, and Gregory Pan none. It means that EVs will need to meet new standards for testing and marking. “Basically,” says VanderWerp, “we’ve looked at how vehicles perform compared to the values on the window sticker, comparing what the label says and what we see in our real-world highway test.”We notice a big difference in how well EVs and cars run on gas work. The range is the most important thing to consider when buying an electric vehicle for the first time. On Car & Driver’s 75 mph highway test, more than 350 internal combustion cars got, on average, 4% better gas mileage than what their labels said. On the other hand, the middle range of an EV was 12.5% less than what was written on the price tag. How the range is calculated is one reason EVs don’t live up to promises. After the city range and highway range data are made separately behind closed doors, customers only see the total. The city grade is 55% more important than the overall score because that’s where EVs usually do better. Because the range predictions are too high, driving on the highway in real life is more challenging. The study suggests putting out city and highway range data so that people can better understand what a vehicle can do. This is similar to how fuel efficiency numbers are put out for gas-powered cars. The claimed range number is also based on how the tests were done. Car and Driver’s real-world test was done at a steady 75 mph, but the EPA’s cycle has a speed that changes as the trial goes on. EVs have a more extended range because they can recover energy when they slow down. This is made worse because the total rating is slightly skewed toward city results, even though this is bad for gas cars, which work best when their rpm stays the same. A reduction factor is added to the first EPA data to account for the effect of higher speeds. The EPA’s highway cycle is done at much slower speeds than Car and Driver’s 75 mph test. Automakers can choose between a two-cycle test (in which a typical 0.7 adjustment factor increases the data) and a five-cycle test (in which the data is decreased by a smaller amount, which raises the label figure). So, estimates of how far different cars can go are sometimes other. VanderWerp says that there is a balance. “The marketing team wants to highlight a wide range of numbers, but you should be conservative with customers,” says the author. As a result, numerous brands employ distinctive methods. Most of the time, the range estimates given by BMW, Mercedes, Audi, and Porsche are low. This lets us match or even beat the range numbers from Car and Driver’s field tests. On the other hand, Tesla tries to come up with a pretty number for its window stickers but ends up with results that are less than the label value of most EVs. When you compare the range of EVs from different companies, the effects might not be as dramatic as the numbers suggest. At highway speeds, the ranges promised for a Tesla and a Porsche are about the same: 400 miles for a Tesla and 300 miles for a Porsche. The report suggests that the EPA raise the reduction factor to 0.6 so that the range figures are closer to the real-world efficiency test results. But it’s also essential that every car goes through the same testing process. VanderWerp says that every car company could use the five-cycle test actively to get a better reduction factor, but more customers would be unhappy with the results. “They should all be tested the same way, and the tests should be more realistic than they are now.” On the SAE website, you can read the whole thing.
