The sound of a car 's clackson was developed and used 100 years ago, but can cause traffic noise to pedestrians and drivers, which can be harmful. We have previously proposed a new familiar Clackson sound with a different rhythm or tempo using the existing Clackson. However, since the existing Clackson sound is needed in emergency or special cases, this study newly proposed a compatible Clackson sound method. First of all, pressing the center part of the handle of the driver's seat while driving starts a rhythmic clack sound, on the other hand, after a short touch, you can press and hold down to use the existing Crackson sound. We usually use a human-friendly Klaxon sound that is designed considering 100 people's hearing fatigue, brain wave test, stress index, etc., and when using the existing Klaxon sound in the case of emergency. Therefore, the proposed Clackson sound can be used without any major change in all the cars on the market, so that it is possible to minimize the opponent's retaliation during driving.The sound of a car 's clackson was developed and used 100 years ago, but can cause traffic noise to pedestrians and drivers, which can be harmful. We have previously proposed a new familiar Clackson sound with a different rhythm or tempo using the existing Clackson. However, since the existing Clackson sound is needed in emergency or special cases, this study newly proposed a compatible Clackson sound method. First of all, pressing the center part of the handle of the driver's seat while driving starts a rhythmic clack sound, on the other hand, after a short touch, you can press and hold down to use the existing Crackson sound. We usually use a human-friendly Klaxon sound that is designed considering 100 people's hearing fatigue, brain wave test, stress index, etc., and when using the existing Klaxon sound in the case of emergency. Therefore, the proposed Clackson sound can be used without any major change in all the cars on the market, so that it is possible to minimize the opponent's retaliation during ...