Shared Authority Mode In Uncertain Situation

In a partially automated driving system, the driver is expected to respond to a request to intervene from the system in an emergency situation or functional limit. Currently, with regard to the transfer of driving authority, significant research has been performed on how to address the request that occurs when a functional limit is approaching. However, generating the request immediately before the limit may not allow the driver to operate in time. Consequently, a deterioration in vehicle stability will occur. Therefore, it is necessary to address the situations before reaching the functional limit named "uncertainty situation". In this situation, the system should inform the driver without decreasing the driver's trust on the automated driving system. This is because the driver may not be convinced of the system if the request occurs many times without the functional limit. Therefore, in this research, we propose to introduce a shared authority mode that reduces the driver's workload under uncertain situations because of the partial responsibility for the driving operation. Experimental results from using a driving simulator indicated that the proposed method reduced the reaction time from the time a request was generated to the time of driver takeover operation, thus improving vehicle stability and reducing the workload.