4 times faster at the same fuel cost
Arrive exponentially faster by driving on the roofs on other cars on long stretches of a highway
When you go for a stroll while on an airplane, it may feel like you're dashing along at your usual 4-6 kmph. But in reality you're going many times faster, because the plane is also in motion.
Caterpillars in the Amazonian rain forest figured that out. Imagine if we could take advantage of this effect on packed highways. In rush hours, our highways are packed with cars, but only in a single layer. If we could swarm those cars, at least some of them would arrive faster, using less energy. And those below could benefit from taking fees for hosting them on their roofs.