Hermann Zehender, long-time employee in product engineering with 40 years of professional experience in all kinds of road tests, knows this too. He steered the 18-metre-version of the Citaro, the Citaro G with anti-jackknife control, over the prepared course at the Safe Driving Centre at the Hockenheimring. "Hold on with both hands, that's not a joke", demanded instructor Andreas Türk, who accompanied the rides and explained the anti-jackknife control. The bus didn't move an inch until everyone was seated safely and holding on as required – and rightly so, because what Zehender demanded from the bus is not something anyone would want to experience in regular line service. At moderate urban speeds of up to 50 km/h he used brief but strong steering inputs to try and get the rear end to swing out again and again – but the Citaro remained unfazed, and the rear end stoically followed the provocative track steered by the driver. But those seated on the bus gained a vague understanding of the tremendous forces that must be acting on the components of the articulated joint and how well the system actually performs.