You may see language like, "Please preserve all evidence related to this incident," in a letter from a lawyer, insurer, or injured person shortly after a crash or other serious event. That is usually a preservation letter: a written notice telling a person, business, or agency to keep documents, video, electronic data, vehicle parts, and other material that could matter later in a legal claim.

Its practical purpose is simple. Evidence can disappear fast. Surveillance footage may be overwritten, truck electronic data can be lost, damaged vehicles get repaired or scrapped, and weather conditions can erase physical signs at a scene. A preservation letter puts the recipient on notice that the evidence may be relevant to a personal injury case, wrongful death claim, or insurance dispute. If they destroy or fail to keep it after receiving notice, that can lead to arguments about spoliation of evidence.

In North Dakota, that can matter a great deal after highway crashes, especially on long rural stretches patrolled by the North Dakota Highway Patrol or on heavy truck routes like US-85. Harsh conditions, remote locations, and severe cold can change a scene quickly and affect vehicles, electronic systems, and witness availability. A preservation letter does not guarantee the evidence will be saved, but it is often one of the earliest and strongest steps for protecting proof that may later support liability, damages, or causation.