Finding trace evidence through scope reduction and applying its straightforwardness in traffic accident investigation

Objective: This report examines how evidence appears according to the issues of traffic accident investigation, and examines the immediacy of the evidence and its meaning. Background: In traffic accidents, there may be trace evidence related to the issue. When the investigator does not make a judgment based on evidence, the truth of the case may be distorted by various mistakes that humans can make, such as confirmation bias and eyewitness illusion. Methods: By investigation process of two traffic accident cases that violated the central line regulation, we examine how evidence was found and its immediacy works. Results: As evidence, we presented a piece of plastic attached to the underside of the vehicle and several photos showing the distribution of vehicle debris at the time of the accident. Evidence that we found can be easily understood by anyone with common sense and has undeniable clarity in figuring out the facts. The evidence found could immediately overturn the police’s investigation results and be accepted as primary evidence by law enforcement agencies. Conclusion: Every incident has a judicial problem, and there can be one or more pieces of evidence for resolving it, which can manifest itself in many different ways. When evidence with immediacy is found, the case can be resolved easily and clearly. The field of forensic science can help find such evidence.