Traffic accidents are a serious problem that consistently result in loss of life, injury, and material loss. From a positive legal perspective in Indonesia, criminal acts that result in the loss of life due to negligence in traffic are strictly regulated in the Criminal Code (KUHP) and Law Number 22 of 2009 concerning Traffic and Road Transportation. These regulations aim to provide legal certainty and a deterrent effect for any perpetrator of traffic violations that result in fatal consequences. In social reality, the resolution of a crime is not solely carried out through formal legal instruments, but can also involve customary legal mechanisms adopted by the local community. In the case of a traffic accident that resulted in the loss of life that occurred in Kotawaringin Lama District, the cause was, among other things, driver negligence and unintentional drivers. When a traffic accident occurs, local residents do not immediately contact the police but instead go to the Damang or Mantir Adat in the area where the accident occurred. The results of the study show that the resolution of criminal acts of loss of life due to traffic accidents in Dayak Customary Law in Kedamangan Kotawaringin Lama emphasizes the principles of restorative, deliberation, and kinship.