The homepage of the "Norwegian Safety Investigation Authority" is much more informative and the 2 documents have interesting photos, e.g. closeups of where the wood broke.<p><a href="https://www.nsia.no/Road/Investigations/22-441" rel="nofollow">https://www.nsia.no/Road/Investigations/22-441</a><p>It does not state why they conclude the cause was overload, only that <i>"Uncovering the technical causal factors for the collapse of the Tretten bridge has been challenging. The expert group has worked its way through several hypotheses to be able to exclude non-relevant fracture mechanisms, by connecting findings to computational analyses. There was significant consequential damage to the bridge structure, both from the collapse itself, the impact with the ground and the salvage work, and it has been challenging to separate these from each other."</i><p>Personally I would think that a bridge should be able to handle "A passenger car and a truck with trailer loaded with lime were on the bridge when it collapsed".