Our series of posts titled "What Does This Button Do?" has been quite popular, revealing the true nature of various peculiarly labeled buttons in new cars and trucks. Today's entry, pictured above, takes things in an unexpected direction. What does this button do? Absolutely nothing!
As I explain in my 2012 Toyota Prius review, the button is found on the venerable Prius and some other Toyota and Lexus hybrids. Unlike the other buttons we've highlighted, its function seems clear: EV equals electric vehicle. It's meant to activate an all-electric EV mode that allegedly allows for gas-free acceleration. Only it doesn't.
The EV mode is purported to raise the threshold at which the gas engine kicks in, but it's nothing like the Chevrolet Volt — which runs electric-only under full acceleration — or even the Prius Plug-In, which gives respectable electric acceleration to 60 mph. Prius owners will argue furiously that they drive all-electric all the time, up to about 30 mph. Maybe — downhill, with a stiff tailwind or with no one behind them. In actual traffic, these are the people you want to pull from their cars and beat with a soy burger.
In my experience, the Prius accelerates solely on electric power less than people seem to expect, but turns the engine off far more frequently than you'd imagine when coasting. Ultimately, what matters are the results, and here the Prius consistently delivers, with an EPA estimated 50 mpg combined. But the EV mode button? A ruse! It belongs in the same category as an elevator's "close door" button. I like to imagine that when you push the EV button, somewhere an elevator door closes. …. If not, well, it's just taking up space.