Cars in the "tandem class" were two-seaters with the occupants sitting one behind the other. In this case, you might question the use of the word "car" since this vehicle looks an awful lot like a motorcycle. It does have four wheels, though. It's just that two of them fold up and out of the way while driving, dropping down at low speeds to provide stability.
Its bike-style body saves a lot of weight, which confers advantages in both efficiency and performance. In tests, this car got to sixty miles per hour in a relatively blistering 6.6 seconds.