Development engineer Volker Reichl has already approved and optimized the Citan in the wind tunnel five times. He clearly increased the aerodynamics and thereby reduced the fuel consumption down to 4.3 litres per 100 kilometres. In the second testing the wind tunnel simulates a drive through the rain. This is how the engineer checks the dirt deflection at the side-view mirrors and the side windows. For this purpose he puts his focus on the exterior mirrors and the A-pillars and could achieve an improvement here as well. Thus the engineer makes the Citan safer when driving through rain and snow. The film shows Volker Reichl and the wind tunnel at work.