Manipulating an electronic device when driving is regarded as very unsafe. However, it is not unusual to see drivers interacting with all sorts of devices behind the wheel. In Spain, a new legislative initiative pursues punishing drivers with two points in the penalty point system if operating a navigator when driving. In order to illustrate the negative consequences of this behaviour, we set 43 subjects to drive in the driving simulator SIMUVEG while introducing directions in a navigator. Several performance measures were recorded for these subjects. Intrasubject comparisons revealed significant differences for many of these measures providing evidence of the negative consequences of such interactions.