How do drivers interact with navigation systems in real life conditions?: Results of a field-operational-test on navigation systems

• Two types of navigation systems were compared in a Field Operational Test (∼1,000,000 km).
• Drivers preferably made inputs to both types of navigation system in low demanding situations.
• Drivers adapted to the distraction during system inputs by decreasing their speed and distance to the lead vehicle.
• No safety critical impact of making inputs was found.
• Results provide insight into how navigation systems are handled in real traffic.

As part of the project euroFOT, the impact and usage of navigation systems was studied in a Field-Operational Test (FOT). The usage and handling of two HMI-solutions for navigation systems – one was nomadic and the other integrated – were investigated during daily drives. For N = 99 drivers, data was recorded whenever drivers used their vehicles during a three month period. During these three months, drivers used an integrated navigation system for a month and a nomadic device for a month. In the third month, they did not use a navigation system at all (baseline). Drivers preferred system handling in low demanding driving situations, like standstill or at very low speeds. If system handling occurred while the vehicle was moving, then an adaption of speed and following distance was observed. No increase of critical driving situations, like very close distances, could be found during system inputs. Results indicated that drivers were cautious when they interacted with the navigation systems. They adapted their system handling to the demands of driving and there is no indication that driving safety was jeopardized. These results help to gain a better understanding of how experimental results on driver distraction relate to unobserved driver behavior during daily drives.