A driver apparatus for a differential bus is provided, having a first transistor and a fourth transistor which are connected in order to drive the bus to a dominant state, and a second transistor and a third transistor which are connected in order to drive the bus to a recessive state. The driver apparatus also comprises a collision detection circuit which is set up to detect a collision state on the bus on the basis of measurements of currents through at least one transistor of the first, second, third and fourth transistors.