Most police officers are not accident reconstruction experts and they don’t pretend to be. In fact, their basic function when it comes to police accident reports is to copy down the driver, insurance, and registration information and take a statement from each involved party. Based on those statements and the officer’s visual observations at the accident scene, the officer may make a preliminary assessment as to the contributory factors, but when the officer did not actually witness the accident himself, any finding of fault is not definitive and can certainly be proven or disproven as a claim or case progresses. This is not to say that the police report is not given credit or relied upon (insurance adjusters are notorious for relying on the police report when it’s in their insured’s favor), but an officer’s after-the-fact determination of how an accident occurred when he himself did not witness it is hearsay and is generally inadmissible at trial. If the officer is subpoenaed to testify at trial, he will certainly testify to what he observed at the scene when he arrived (such as the presence or absence of skid marks, the positioning of the vehicles, and any visible body damage), but unless he is an accident reconstruction expert, which a precious few officers are, he will likely not be permitted to offer his opinion on how the accident occurred or who is at fault for causing it.