The first mass-produced car to feature a unibody construction was the Lancia Lambda, which was introduced in 1922.
The Lancia Lambda was a luxury car produced by the Italian automaker Lancia from 1922 to 1931. It was designed by Vincenzo Lancia and his chief engineer, Francesco De Virgilio. The Lambda was the first car to feature a unibody construction, which means that the body and frame of the car were integrated into a single unit. Prior to this, cars were built with a separate body and frame that were bolted together.
The unibody construction of the Lancia Lambda made it lighter and more rigid than other cars of the time. This allowed it to handle better and have a more comfortable ride. The Lambda was also equipped with an independent front suspension system, which was another innovation at the time.
The Lambda was powered by a V4 engine that was mounted in front of the driver. It had a top speed of around 80 mph and was available in several different body styles, including a sedan, a cabriolet, and a coupe.
The success of the Lancia Lambda paved the way for other car manufacturers to adopt the unibody construction method, which is now the standard for most cars on the market today.