Volkswagen ID.4 & Tesla Model Y Highway Range Test — A Look Behind The Numbers
Car and Driver has a standard loop it has used to test how far electric cars can travel at 75 mph on the highway. Anyone who owns an electric car knows that the faster they go, the sooner the battery is drained. It’s mostly a function of aerodynamics — it takes energy to push a car through the air and the immutable laws of physics say wind resistance is geometrically proportional to speed.
Another way to put it is that if you double your speed, you quadruple the amount of wind resistance. You can try it for yourself. Stick your arm out the window of a car moving at 30 mph with your hand straight up against the wind. Now increase your speed to 60 mph and try the same thing. The wind pressure on your hand will be four times as great as it was at the lower speed.
Recently, the magazine took a Volkswagen ID.4 First Edition out for a drive on its highway test loop and found the car had a range of 190 miles when travelling at 75 mph. The ID.4 comes with a single motor and a 77 kWh battery. The EPA says it has a combined highway/city estimated range of 250 miles and rates the ID.4 at 89 MPGe on the highway. Car and Driver measured an actual MPGe of 82 MPGe.
How Did The Tesla Model Y Do?
In a prior test, a dual motor Tesla Model Y with a 75 kWh battery went 220 miles in the Car and Driver highway range test and scored a 94 MPGe rating. That’s better than the ID.4, but there are some footnotes readers should be aware of. The Model Y test took place on a day when the ambient temperature was 75° F. The ID.4 test was conducted with the mercury showing an outside temperature of 40° F.
Anyone who owns an electric car knows ambient temperature has a significant impact on range and charging speed. Also notice that the Model Y was further away from its EPA combined range rating of 326 miles and highway MPGe rating of 117. In other words, the ID.4 was closer to the EPA estimates in real-world driving than the Model Y.
These test prove nothing, of course. There’s a reason why the EPA testing protocols require standardized test parameters that eliminate variations in temperature so that the results are more consistent. They also are conducted indoors according to a standardized driving profile. Different people can drive the same car on the same day on the same roads and get different results.
One can speculate that the ID.4 would have gone a little further on a 75° day and the Model Y would have gone a little bit shorter distance on a 40° day, which suggests the ID.4 and Model Y may not have as great a difference in real-world driving as the Car and Driver testing would indicate. Here’s another factor to consider. The ID.4 First Edition lists for $45,190. The Model Y lists for $48,990. There is an off-book single motor Model Y Standard Range that sells for $39,990, but good luck ordering one or finding a Tesla representative who will admit that car is even available.
The upshot of all of this is that any test like the one performed by Car and Driver is inherently suspect. EPA numbers may not be indicative of real-world driving but they do offer a guide that allows shoppers to compare the features and benefits of different cars. For years, car companies have been saying, “Your mileage may vary. See dealer for details.” That applies just as much to electric cars as it does to conventional cars. So buy the car that makes you smile the widest and be happy. Any electric car sold today is quieter and more fun to drive than any equivalent conventional car and leaves no planet-killing pollution in its wake. What’s not to like?