Motoring's rundown of the five best models that never made it onto the roads despite plenty of style and innovation.
Top 5: Concept cars that should have made it to mass production
1963 Chrysler Turbine Car
The jet age was in full blast, so to speak, in the early 1960s, so what better symbol of the time than a jet car? Chrysler had been working on turbine power since the late 1950s, which culminated with five concepts and 50 "production" models for public testing. The turbine was touted as having fewer parts, ran smoother and produced less pollution than an internal combustion engine. The company even found a way to cool the exhaust, but couldn't make them economically viable and most were scrapped.
1969 C111 Mercedes-Benz
Debuting at the Frankfurt Motor Show, the C111 was a test bed for the German company's engine experiments. The first two versions of the car were powered by rotary Wankel engines, while a third iteration ran on diesel. With the oil burner, the C111 reached 321kph and, in a long-distance run on a track, broke 16 records. In 1991, Mercedes brought the car back to Frankfurt and said it would build it but, in spite of getting 700 orders, the company instead ended the programme.
1970 Ferrari 512 S Modulo
Looking exactly like something fictional family The Jetsons would choose to drive around in if they'd come into some serious money, the Ferrari Modulo saw styling house Pininfarina really stretching the limits of its wild imagination when it was created and then shown at the 1970 Geneva Motor Show. Crafted using the running gear of an unused racing car, this is one of the most iconic concept cars of all time but, as for entering production, there was one problem: its faired-in front wheels could not be steered.
1988 Bertone Genesis
Back in 1988 the motoring landscape was very different and SUVs were few and far between. But Bertone could see into the future and created the stunning Genesis, using parts from Lamborghini. Gullwing doors up front, sliding doors to the rear and the small matter of a front-mounted V12 engine lifted straight from a Lambo Countach driving the rear wheels. Perhaps the ultimate family car, it was just too insane for most markets to go into production. If it came out today, who knows?
2006 BMW Mille Miglia Concept
BMW's design chief, American Chris Bangle, committed so many crimes against taste that it's difficult to single out any of his creations for particular attention. He's now left the company and BMW is back to building tastefully restrained cars. But the Mille Miglia Concept was a masterpiece. Inspired by the 328 Coupé that ruled the famous Italian race in the 1930s, this concept was a perfect marriage of tradition and modernity and now resides in BMW's museum in Munich. The coolest BMW ever.