a new study in IEEE Transactions on Intelligent Transportation Systems mathematically models the implications of the larger problem: You’re not keeping the right distance from the car behind you.

That may seem counterintuitive, since you don’t have much control over how far you are from the car behind you—especially when that person is a tailgater. But the math says that if everyone kept an equal distance between the cars ahead and behind, all spaced out in a more orderly fashion, traffic would move almost twice as quickly. Now sure, you’re probably not going to convince everyone on the road to do that. Still, the finding could be a simple yet powerful way to optimize semi-autonomous cars long before the fully self-driving car of tomorrow arrives.
Problem is, we’re talking about an emergent property here. “To get the full benefits of this, a significant fraction of the cars would have to have this,” says Horn. “In terms of societal implementation that’s a big factor, because even if it’s relatively cheap, people who implement it will question whether the first car that gets it is worth that investment, because until other cars get it, it doesn’t do a whole lot of good.”
“It sounds pretty drastic, but the benefits are huge,” says Horn. “We’re talking about a potential doubling of throughput, huge decreases in CO2 emissions, a lot of aggravation reduced and fuel used.”

Source: Math Says You’re Driving Wrong and It’s Slowing Us All Down | WIRED