Automotive history is rife with innovation. Possibly even defined by new ideas. But while Mr. Gretsky's aphorism of missing 100% of the shots you don't take is true, you still miss a few that you do take. And with cars, there are plenty of good ideas that failed in the market for one reason or another.

More recently, good ideas can fail to take off simply due to the realities of the modern automotive business. Cars are standardized to a high degree, so when something new comes along, it faces a headwind against adoption. Fail to reach critical mass, and there's not enough volume to sustain production, let alone long-term parts supply. Audi's short-lived UFO brakes are a great example. It was an unconventional design with the rotor mounted inside the disc—the resulting domed shape of the carrier made the disc look like a flying saucer. But the layout allowed for larger swept area for a conventional disc inside an equivalent wheel diameter. In other words, better braking without the weight penalty of larger wheels. That wasn't enough of an advantage to overcome a few early problems with the system, and it faded into history after a few years.

Other breakthroughs get superseded by existing technology, or just turn out to answer a question nobody asked. Like Michelin's PAX tire system, most notably used on the Bugatti Veyron supercar but also found on the Honda Odyssey minvan. With a locking bead and a rubber ring mounted on the wheel to support the tire in the event of loss of pressure, it was a foolproof run-flat system that could run longer. It was also expensive and complicated, and required service locations to buy new equipment. It also came out right when conventional run-flat tires were becoming widely available. What's more, the reliability of regular tires has improved so much that even those more affordable run-flats are hardly necessary for most of us.

What other innovations can you think of, and what kept them from changing the automotive world? Let us know in the comments.