Design of an HMI System Promoting Smooth and Safe Transition to Manual from Level 3 Automated Driving

We designed an HMI system to induce a smooth and safe transition to manual driving from Level 3 automated driving with using voice guidance, alarm sound, HUD and interior lights. On the route to the transition zone, the HMI system supplies two preparation zones to regain the awareness of driving and speed. An experiment and an investigation clarified that the HMI system is more effective to induce smooth and safe transition to manual driving than another HMI system for comparison with only alarm sound and HUD. It is also suggested that preparation zones are important for drivers to take over driving readily with concentration.