The aim of this research was to analyse the consequences of interacting with more than one in-vehicle information system (a navigation system and a mobile phone). The performance of 16?elderly drivers (62 to 78?years old) was evaluated and compared to the performance of 16?younger drivers (34 to 47?years old). Subjects were asked to drive a vehicle in a real road and to interact with one and two systems simultaneously. The drivers' performance was analysed for intersection man?uvres. Results showed a global effect of age and system condition (one system and two systems used simultaneously) but no interaction between age and system condition. These results reveal worse performances for the older group compared with the younger one, worse performances when both systems are used simultaneously than when only one is used, but a similar impact of the two system conditions in the two age groups. Conclusions drawn should be moderated due to the limited experience of the participants with the navigation systems.