of fig1 in fig2 corresponding parts of the bus 1 are indicated by the same numerals as in fig1 in fig2 the bus 1 is shown with its roof construction in the open position the roof element 15 b has to that end been moved over the guide rail 13 b from its original position see fig1 to a position under the roof element 15 a subsequently the two roof elements 15 a 15 b have jointly been moved to a position under part of the roof 12 the seat rows 11 c 11 f are thus no longer covered the seat rows 11 a and 11 b are covered by the roof 12 and the stored roof elements 15 a and 15 b this position of the roof elements 15 a and 15 b is referred to as a non covering position or state herein after all the seats 11 a and 11 b and the roof elements 15 a and 15 b are covered by the roof 12 since the roof element 15 b is smaller than the roof element 15 a and the roof element 15 a is in turn smaller than the roof 12 the roof elements 15 a and 15 b do not experience any hindrance from the wind or the like while driving in the thus stored position shown in fig2 fig3 a shows an alternative embodiment of a bus 61 according to the present invention the bus 61 exhibits a great deal of similarity to the bus 1 shown in fig1 a 1 b the body 62 is comparable to that of the bus 1 of fig1 a and 1 b with this difference that the bus 61 has rear side wall parts 64 a and a roof part 72 a at.