>>1115102for vehicle aerodynamics one of the largest issues is vortices created by openings or irregular shapes in the sides
the brick with somewhat rounded angle design isn't actually all that bad as long as the sides are very smooth
note that on long haul coaches, the doors and cargo compartments are completely flush with the sides
the gaps between body panels are as small as possible
the bus rides close to the ground, which also helps quite a bit, as air between a vehicle and the ground is very turbulent
also, they are much longer for their front surface area than a car or truck is
this means that they can move more people per volume of air displaced than cars
