AbstractBackgroundIn Japan, around 30% of the older adults have dementia or MCI, and many of them drive daily. They have encouraged to surrender their driving licenses, but that have not been effective. It's said that older adult drivers are not aware of the dangers of driving, and they're not willing to switch to safety support vehicles. Hence in this study, I examined the relationship between MCI drivers’ driving behavior and their awareness or acceptability of safety support.MethodIn this study, the 196 subjects including MCI or dementia drove in a driving school to induce dangerous driving. When their behavior was dangerous, the following safety support was provided, and the changes in driving behavior and awareness were recorded: 1) The instructor sitting in the passenger seat gave advice at that moment, 2) The instructor gave advice after the experiment, 3) A alert was sounded, 4) Their driving were evaluated by scoring. After a few months, it was checked whether the subjects remembered the behavior and advice. The driving behavior on public roads was also recorded, and the awareness was investigated when the advice given later.ResultIt was found that MCI drivers behaved dangerously when the driving load was increased by multitasking, whether in a driving school or on public roads. However, since they underestimated their own dangerous driving and did not recognize it as dangerous, the post‐experimental advice was found to be ineffective. On the other hand, it was also revealed that giving advice or sounding a warning sound at the moment of dangerous driving increased the mental load of MCI subjects and might have negative effects on their subsequent driving. In the case of MCI drivers, the advice induced risky driving because they became too attached to the advice and neglected other driving skills.ConclusionAlthough immediate and specific driving advice or warnings are generally considered effective, they have been found to have a negative effect on MCI drivers. On the other hand, it is necessary to develop safe driving support measures that are immediate but do not give too much information, because drivers forget about dangerous driving over time.