Ad hoc train

From PDI

Trains as we know them are very efficient when it comes to moving lots of cargo from one place to another, mostly because of low air resistance, low rolling resistance, low labor cost, and high cargo density. As an additional plus, most trains can use electricity supplied by wire. It's got several drawbacks, though, the most notable being the infrastructure limitations.

Using a car or truck on the other hand, is often faster and more flexible because of the extensive and versatile road infrastructure. It can move cargo from source A to destination B without stop - no need to load cargo onto another vehicle. Drawbacks here are high labor cost, high air resistance, rolling resistance, and the low cargo density compared to a train.

Now, we don't really need rails to form a train. Cars equipped with communication and regulation technology can drive with less than a meter distance to the next car. When the driver in front slams in the brakes, this can be communicated to the cars in the train/convoy, and they can start braking only milliseconds later. When the first driver accelerates again, so do the others.

Cars wanting to form a convoy enable "convoy seeking mode", and hook up to the first found car with the same mode. Cars wanting to leave, turn off convoy mode and change file. Remaining cars rejoin if feasible.

Taking the idea a bit further, imagine bumpers double as buffers. Cars wanting to form a convoy/train actually physically connect to form a train of cars. This gives the opportunity to turn off every second or third car engine, thus further reducing fuel consumption and CO2 emission. To distribute costs, engine use can rotate among the cars in the convoy.

Further improvements can be had by reusing information already in most cars, like using GPS navigating systems' destination to form and regroup convoys. To keep drivers not in the first car to be alert and occupied with driving, the view from the first car can be recorded and distributed to the other cars, projected on the windshield for instance.

To summarize, this brings two important railroad advantages to today's road, namely low air resistance and high cargo density. In addition, road capacity will be multiplied, as you get one car approximately every 5 meter, instead of one car every 50 meter for cars driving in 80km/h (or 60 m/h). This has the potential of a tenfold increase in capacity! Of course that can't be obtained as cars entering/leaving the convoy will need room to navigate. Even though, if a two-fold increase can be had during a rush, that would alleviate much of the traffic jam problems seen in most cities.

Interestingly enough, this can be done reusing the road infrastructure of today.