Why is the number of car accidents in the US on the rise?

The US Department of Transportation began an annual census of motor vehicle deaths beginning in 1975. In that year, 44,525 deaths were reported, and the first few years of the census, the numbers rose each year. The highest total reported was 1979, when 51,093 people were killed in crashes. In 1992, the toll dipped below 40,000 for the first time and then stayed between 40,000-43,000, until 2008, when fatalities dropped to 37,423.