AutoRail: Autonomous, Simple, Energy-Efficient Mobility - A Vision

0. AutoRail-System - as a whole - in three sentences

The AutoRail system is a lifted rail system at around four meters height with embedded power and data lines and autonomous vehicles driving on it. Running on batteries they can also be driven on usual roads, but on these rails they can easily drive on line electricity, autonomously, cooperating and physically connecting making traffic jams very unlikely. The system is extensible being able to hold many infrastructures at once, intrinsically a power and data line, but also water and waste water pipes or solar cells mounted as a roof.

1. The Problems

1.1 Energy Storage + Efficiency

The combustion engine dominated the mobility of the 20th century. The lightweight and yet abundant energy storage (gasoline/diesel) only made this possible. It provided the flexibility to create simple autonomous vehicles, cars, a great invention, truely.

But the aimed-at decarbonization of the 21st century demands a replacement. Batteries and Hydrogen aim at a shortcut solution there, simply replacing the storage system (also replacing the combustion engine with a simpler electromotor).
Nevertheless, also for those the energy has to be stored inside the vehicle.

Unevitably, this brings the risk of fires, as much energy is stored in a small volume.
Also, these energy containers have to be carried along the way. Especially for batteries, this creates a lot of dead mass in the vehicle, as usually not the full capacity is needed.

Most importantly, there are also conversion inefficiencies for all of those systems, which can only partly be overcome.

These problems are inherent in all flexible, unconnected systems, be it cars, drones, autonomous flight taxis. So one needs a good solution at the energy storage front to make these attractive and useful. But no (or only limited) need of such a storage system would make things easier for sure.

1.2 Autonomy

The autonomous car has been a hot topic during the 2010's. Although, there were major steps and there are vehicles running partly autonomous already on the road, it did not make a true breakthrough yet.

The partly unevitable connection to the internet changes such a car from a human controlled weapon (with the driver also taking risk) to a potentially remote-controlled one, with no risk for the operator. Eventually, humans are out of control at all.

Furthermore, there are still problems with unseen situations. The reliance on unforseeable reasoning of artificial intelligence is criticized by insurances, regulators and not to forget the humans being transported.

The more complex systems get, the more probable weak links in the chain are.

But the impact of such an autonomous mobile systems would surely be tremendous. On one side it would take taxis', buses' and trucks' drivers jobs, but it would also make common transport even more affordable.
These drivers were really the drivers of globalization in the past century making global economic cooperation possible at all.

With autonomous mobility another big reliance of industrialization on human individual work force would be relieved, making the easy distribution of more wealth only possible.

But it would be nice to have such a system understandibly reliable, non-hackable as well.

1.3 Simplicity, Scalability

Scalability is a big point for such autonomous systems. One some scales, autonomous, individual driving is surely more efficient. The modern phenomenon of traffic jams shows limitation of this way of mobility. Public mass transport in trains and buses is much more efficient for a situation, where many people want to move along the same path.

There are phase-transitions, emergent effects, that have to be accounted for.
For example, fast, computer-based communication could obviously detect these and densify traffic to make it faster when needed.

But these systems have to be constructed failsafe, optimally mechanically failsafe. Too often software bugs have caused severe damage to opt for a software only solution.

2. Proposed Solution - In parts

2.1 Introduction

While often these problems are dealt with separately, this should be an attempt to solve them in a combined way. It involves, as for all other transportation systems, a kind of cooperative action and cannot be established by a single company.
A car is as slow as the road permits that it is driving on.

The following parts describe subdecisions all contributing to the better whole. They provide an understanding of why exactly this and no other system is needed.

2.2 A Rail system

Why do we want a rail system? Rails are energy efficient, you don't have to steer, you just follow the path you want to go anyway. It reduces the degrees of freedom to be controlled, you can only accelerate and brake (and turn right at crossings). Also all other participants do this, so it is very simple to predict movements of others (if you want to as a safety redundancy).

2.3 Dimensionality

Railroads are expensive because they are commonly built to carry a lot of weight. This is sensible if you have only large machines to operate on it (trains) and maximizes the productivity of one human operator. But things change, if you have an autonomous system. You don't have to maximize the effort of one human operator. Here mass scale to be transported as a whole is the mass of a single human being. One usually doesn't want to split that.
So one doesn't need to transport 20 metric tons per axis, but actually something like 300 kg (to be on the safe side), maybe a bit more for other common things or animals.

2.4 Energy

The role energy storage plays in this system is that you don't need it. At least not when vehicles are moving on the rails. The energy (electricity) should be provided on electric lines in between the rails or at the top as for usual trains.

Vehicles can carry batteries with them to move on after leaving the rail system. It is crucial to enable them using also existing roads and streets. Otherwise it will be poorly adopted as, in the beginning, the individual benefit is negligible.

2.5 Position

There are already too many things on the ground competing for space. Lifting the rails to a height of around four meters, will make the system more costly and broadens safety considerations.

But, here the limited weight of the vehicles comes into play. The construction doesn't have to hold tens of tons per axis, but only some hundred kilograms. So cost is someway limited here.

This lift also minimizes interactions with other mobile, autonomous systems, people, other cars, animals. So it plays a crucial role for making things easily, safely autonomous.

There are also two other options, which are considered in other approaches. One is flying. It obviously minimizes any need of infrastructure and allows for high speeds. But it also doesn't solve the energy storage problem.
The second one is most prominently followed by the so called "Boring Company". Its proposal is essentially going not up but down, underground.
While this has some obvious advantages (you do not have to look at it), it has to deal with safety issues and is though some technological advances really expensive.

2.6 Coordination

While most modern systems rely on wireless communication, it might be beneficial to have communication wires in between the rails as well. You can only hack them, when you are really on the system (or very close). And a vehicle can easily monitor if it is still connected (physical contact). You can also localize interaction by simply cutting the wire at specific points.

Once systems communicate, they can also cooperate. Two rail vehicles on the same way can connect physically. First, to save energy by having a smaller aerodynamic resistance. Second, to enable a mechanical braking system, making rear-end collisions nearly impossible. And third for a global benefit, they make traffic more dense, reducing the risk of traffic jams.

This coordination system is at the core of the technology. It not only has to cope with sudden brakings (although these should occur very seldom). Vehicles have to get on and off the rails, the need to get out of or into the chain at crossings. This should happen autonomously and efficiently of course, but all relevant data is directly at hand due to the direct wired communication.

2.7 Combination with other Infrastructure

You might have heard the phrase: "Think things together that belong together". This rail system aims at being a new kind of infrastructure.

Why not combine it with other infrastructure? When it already provides electricity for the vehicle on it, why no provide electricity for the house nearby or the village at its end? Same for wired internet connection and water / waste water connection. While usually these were dug under streets, hardly accessible, they could be easily mounted underneath the rails.

If you have multiple rails crossing, these links make the system more resilient also for other infrastructure. If one link breaks for whatever reason there are usually more edges connecting nodes.

Also one can build cycle paths underneath, with the rail construction providing shade. In between the rails or mounted as a roof, one can place photovoltaic cells providing the energy for the movement and the electric grid. The electric power lines are right there.

This is only possible by the modular/extensible design that we imagine. In doubt it is always sensible to opt for more than less infrastructure.