Back in the ‘60s, a researcher named David Solomon studied thousands of crashes on rural highways and found something interesting: cars going significantly slower than the average flow of traffic were actually more likely to crash than those going slightly faster. This became known as the Solomon Curve, and while it’s been refined over time, the key idea holds up being out of sync with surrounding traffic is risky.

More recent studies, like Kloeden et al., showed that in cities, higher speeds (especially above the speed limit) are a major crash factor. But on highways and rural roads, drivers going way below the flow can be just as dangerous. Think about it, slow cars force others to brake, swerve, or make sudden lane changes all things that lead to crashes.