I haven't found a link to less generalized data. What were road/traffic/driver conditions in the fatal accidents?

Were there more accidents, or were accidents themselves more fatal? What percentage of fatalities involved a semi? Happened on freeways?

What if climate change is the culprit? Road conditions have deterioriated as a result of changing weather patterns. Drivers have deteriorated as mobile devices become more central to our lives. I doubt that the 8% increase in fatalities is best explained by a 3% increase in miles traveled.