The roof (12) is assembled of several segments (22, 24, 26, 28) sliding in lateral guides provided at the longitudinal struts (14) above the side windows. The rear window (32) can be lowered into a frame in a first step, a switch (38) is operated, activating a conveying system moving the row of segments (20) towards the back of the car. As soon as the rear edge of a segment (22, 24, 26, 28) exceeds the body of the vehicle, the part can be manually removed and stored in a compartment (36), provided at the back of the car.