This procedure uses the same EPA city cycle (20-mph average speed over 7.5 miles with 18 stops) and highway cycle (48-mph average speed, 10.3 miles) used for fuel-economy tests of all light-duty vehicles. Both cycles feature extremely gentle driving; the most aggressive acceleration would be equivalent to an 18-second 60-mph time. Between city and highway loops, the test calls for a steady speed of 55 or 65 mph to deplete the battery. The EPA knows these low-speed tests aren't representative of the real world, so every EV's window-sticker range is the product of an adjustment factor that yields a more realistic consumer-facing figure.
This is where it gets interesting. The default adjustment factor reduces the window-sticker range by 30 percent. So a car that achieves 300 miles of range during the city-cycle dynamometer test ends up with a 210-mile city rating. However, the EPA allows automakers the option to run three additional drive cycles and use those results to earn a more favorable adjustment factor. Currently, only Tesla and Audi employ this strategy for their EVs, and Tesla scores the most advantageous results, with adjustments that range from 29.5 percent on the Model 3 Standard Range Plus to 24.4 percent on the Model Y Performance. If Tesla had used the standard adjustment factor of 30 percent, the Model Y Performance's window-sticker range would drop to 292 miles. But because Tesla takes advantage of the EPA's alternate methodology, the company can instead claim a 315-mile range.