As more and more functions of agricultural tractors are automated to make farming operations faster and easier, designing efficient driver controls becomes more and more crucial. The French Institute of Agricultural and Environmental Engineering Research (CEMAGREF) and The Ecole Nationale Supérieure d'Arts et Métiers (ENSAM) developed a method to assess drivers' reaction to a new driver controls system including both a psychological and quantitative approach. A physiological approach was also considered, but could not be instrumented in the tractor-cab's environment. A group of eight farmers were used to test the method by evaluating a new automated control system on a tractor. This experiment pointed out that a good indicator of the driver's trust and understanding of the control system was given by the ability to imagine new ways or new conditions in which it could be used.