The aim of this work is to study the platooning of square-back vehicles on top of a road. When two or three bodies are following each other with a short distance between them, the presence of the preceding body changes significantly the pressure force in front of the following one as a weak flow is present in between. The preceding body plays the role of a buckler and so the following body has to face completely different flow conditions. Therefore the drag coefficient of the following bodies can be drastically reduced as shown on the results. But the reduction is strongly linked to the distance between the bodies and the differences are significant. The numerical simulations are performed around simplified vehicles, namely the square back Ahmed body and the simplified European tractor-trailer geometry. The results are also linked to the shape of the bodies.