5. Volkswagen XL1
The Volkswagen XL1 looked more like a concept car than something you’d see on the road. Built to achieve incredible fuel economy, it featured diesel-hybrid technology and an ultra-lightweight carbon fiber body.
While its extreme efficiency and futuristic design seemed impractical for everyday use, the XL1 became a coveted collector’s item and a bold statement of Volkswagen’s engineering prowess.
Learn more about the XL1’s innovation at Car and Driver.