I have always been a fan of novel engineering and willing to spend my own money to support adventurous products. This is why, back in 2003, I was cross shopping two cars that had nothing in common except novel engineering: the Mazda RX-8 with its Wankel rotary engine and the Toyota Prius gas-electric hybrid.

Side note: it is common for car salesman to ask what other cars a particular shopper is also considering. When I tell them, it was fun to watch watch their faces as they work to process the answer.

Eventually I decided on a Mazda RX-8, which I still own. Since then I have also leased a Chevrolet Volt plug-in hybrid for three years. In fact, the exact Volt shown at the top of my Hackaday post memorializing the car. Both of those cars are no longer being manufactured. Meanwhile Toyota's gas-electric hybrids have become mainstream, making them less personally interesting to me.

But Toyota has an entirely different car to showcase novel engineering: the hydrogen fuel cell Mirai. I had the chance to join a friend evaluating the car. He was serious about getting one, I just wanted to check it out and was not contemplating one of my own. While we were waiting for his appointment, we got in the showroom model and started looking around.

And since we were engineers, this also included digging into the owner's manual sitting in the glovebox. The Mirai ownership experience is a fascinating blend of the familiar and the unusual, the strangest item that caught our attention was this water release switch. The manual only said it was for 'certain situations' but did not elaborate. We asked the sales rep and learned it was so water can be dumped before entering places where water could cause problems.

Two potential examples were actually in front of us: the Mirai parked in their showroom was sitting on a carpeted surface, where water could leave a stain. Elsewhere in the showroom, cars are parked on tile or polished concrete where water could leave a slippery surface causing people to fall. The button allows a Mirai to drain its water before moving into the showroom.

Right now commercially the Mirai is in a tough spot. It is at the end of the current product cycle, where three year old units from the same generation can be purchased off lease at significant depreciation while a far better looking next generation is on the horizon. Toyota has a lot of incentives on offer for potential Mirai shoppers. When leasing for three years, in addition to discount up front, all regular checkup and maintenance is free (no oil and filter changes here, but things like checking for hydrogen leaks instead) and a $12,000 credit for hydrogen fuel.

It was not enough to entice my friend, and I was not interested either. I believe my next car will be a battery electric vehicle.