HOUSTON – As Hurricane Florence rolls in from the Atlantic, traffic is rolling out.
South Carolina is reversing the flow along many major routes for the third storm season in a row. The process of making all lanes one-way is called "contraflow," which was never enacted during Hurricane Harvey.
But why?
“You cannot evacuate 6.5 million people within two days, you cannot, it would be chaotic," Houston Mayor Sylvester Turner said.
Houston's mayor stood behind his decision not to call on people to flee America’s fourth-largest city. With a complicated system of highways, it would be hard to make sense of a map of our evacuation routes.
Harvey's incredible amount of rainfall was unprecedented.
Some say many may have ended up drowning in their cars while stuck in traffic trying to get out if a mandatory evacuation had been ordered.
Dozens did die in 2005 when 3.7 million Houstonians tried to leave town in advance of Hurricane Rita just weeks after Katrina.
The storm ended up killing seven people directly, but 90 to 113 people died from things like dehydration and heat exhaustion while attempting to escape in triple-digit weather.
Three years later, only the immediate coastal areas evacuated during Hurricane Ike, a lot fewer people, and things worked much better.
In the end, each storm is evaluated based on threat, enough warning, and the number of easily managed escape routes.
Even then, many wait too late or never leave at all.