The last time a total solar eclipse crossed the US coast to coast, there were only 6.2 million registered motor vehicles in the entire country, according to the Federal Highway Administration (FHWA). Automobiles were still a relatively new fad in 1918, so when the Sun, Earth, and Moon found themselves in alignment that year, the chances of dying in an eclipse-related auto accident was statistically pretty low.
That’s not so for this year’s total solar eclipse, which is set to occur on August 21st. This may explain why federal transportation officials are so alarmed: there were 263.6 million registered vehicles in the US in 2015, and probably a few million more today. More drivers during an eclipse means more chances for distraction, which means more fender benders, or worse. In 2016, traffic fatalities in the US increased 6 percent from the previous year, to 40,200. The two-year increase — 14 percent from 2014 to 2016 — was the largest in more than half a century.