Imagine you get in your car, and drive it to the highway, where you pause for a moment to physically join with 5 or 6 other cars. Now you join the highway, which automatically moves your mini-train of cars at the fastest "safe" speed possible, before moving you off of the highway so that you can decouple from the other cars in your unit, and continue on your way to work.

There would be a few advantages of this system

  1. The total energy cost of the system would be less, since the total drag (from the wind) on the mini-trains would be less than the drag on each individual car.
     
  2. The mini-trains could run on tracks, which could provide the energy for them to move, and to recharge the batteries of the individual cars. It would help increase the range of an electric car, while simultaneously helping solve the problem of "refueling time."
     
  3. It would likely decrease the number of fatal accidents that would occur on highways. Most accidents on highways are the result of operator error, which would presumably be greatly reduced with a computer at the controls. See Google’s driverless car for an existing example of automated driving.