It references this[1] which references this[2] which references this Kayaking paper[3] which says driving has a 152 fatality rate per million participant days if you assume 1 day = 100 miles. That references this[4] which says "The fatality rate per 100 million vehicle miles traveled (VMT)" is 1.52. If you assume 1 day = 100 miles, that means the fatality rate per 1 million days is 1.52. So there was a math error made in the Kayaking paper when they were doing unit conversion. They overestimated by 100x. That error then propagated to Wikidata.

[1] https://www.wikidata.org/wiki/Q999646

[2] https://www.wikidata.org/wiki/Q35627590

[3] https://www.wemjournal.org/article/S1080-6032(03)70564-X/pdf

[4] https://web.archive.org/web/20030323041203/https://www.nhtsa...