Critique of the Paper by Steven Shladover Regarding the Problems and Potentials of Automated Highway Systems
Kirston Henderson, MegaRail Transportation Systems, Inc.
The concept advocated by Steven Shladover is essentially the same as the automated highway system concept that the U.S. Department of Transportation and the several large companies that have recently invested many millions of dollars in development and testing.. From the paper, I don't see anything new that was not addressed by the automated highway system effort. He cites a lot of difficult problems that must be overcome, but they appear to all have been addressed in the previous experiment.
I want to point out what I consider to be several almost insurmountable problems for any type of automated highway system. They are:
1. Weather - It is probably impossible for any automated system to operate in adverse weather unless the traction surfaces are fully protected from water, ice and snow. Outside of such places as southern California, water, snow and ice are real world problems. Even southern California sometimes experiences rain that can be a problem.
2. Human element - Intervention by drivers cannot be allowed in an automated system. Unpredictability and panic of human drivers can quickly render a situation highly dangerous, especially when vehicles are moving at high speeds and following very closely. Close following and relatively high speeds are essential for the increased lane capacity suggested in the paper.
3. Steering Control - Regardless of the level of redundancy provided by computers, actuators, etc., there is no way to preclude the possibility of a vehicle going out of lateral control unless it is mechanically constrained by rails, etc.
4. Braking and speed control - Automated braking and speed control is possible and practical if high levels of redundancy and fault tolerance are provided. Even here, failures must be anticipated, but can be accommodated in a closed rail system where all vehicles are moving at the same speed and control can be exercised on surrounding vehicles by a guideway control system. The laws of inertia are a major aid to precluding end to end crashes. Even with the best of controls, some low-impact contacts of bumpers will sometimes occur in extreme failure conditions. Success of these controls are absolutely dependent upon having full control of all traction surfaces and such control can not be accomplished with open roadways.
5. Unexpected Objects - It is impossible to absolutely preclude objects such a animals, people, etc. from getting into the path of vehicles on any open, at-grade roadway. It doesn't make any difference how many fences are used, such a system is inherently prone to failure. Murphy's law prevails! Thus, any automated system must be either elevated or placed inside tunnels or tubes to assure the absence of unexpected objects. Any other approach depends upon wistful thinking and that is not a safe approach. Any automated system must provide extreme degrees of safety or public acceptance.
6. Modification of Existing Autos - To think for an instant, that we can modify existing automobiles is unrealistic. Cars would have to be specially designed and built for use on any automated highway. With the necessary sensors and fault-tolerant controls, the cost would represent a major increase in cost in even a mass-production situation. The sensor and control systems for conventional automobiles to operate on any sort of automated highway as described in the paper would cost far more than the sensors and controls necessary for operation in closed rail type system. The cost would also be too high for conventional automobiles on a closed rail system unless means is found to otherwise significantly simplify and reduce the cost of the remainder of the automobile. (The MegaRail dual mode automobile will achieve this goal by eliminating the internal combustion engine, transmission, etc.) It is essential that the cost for the user to purchase and use the system can not be significantly greater than that of current systems. Any such increase in cost will doom the system from the outset!
7. Full cost factors not mentioned - The author would lead the reader to believe that the cost of equipping a road lane for automated travel is low because the cost of installing magnets is low. But watch out for and count the full cost! Building special road lanes or freeways is very expensive, even if the right of way can be obtained. The political problem with the general population in converting already overcrowded existing freeways or freeway lanes to lanes reserved for automated travel would be extremely difficult. As a practical matter, it is likely to be impossible in most cases!
The author correctly observes that moving all vehicles a constant speed and close enough together to reduce drag would reduce fuel use and help the air pollution situation. It must be observed that although the assumption is correct, the size of the benefit is not nearly large enough to really solve the problems of fossil fuel shortages and air pollution. Much more is needed. An attractive approach to operate the vehicles with electric power instead of fossil fuels. That, of course, demands electric cars and means to supply the cars with electricity while travelling. Such a feat is difficult to achieve with any type of exposed automated road lane.
It is possible and fully practical to meet the author's goals of automated driving with electric power with a relatively low-cost multimode elevated rail system built over existent road and highway rights of way. Furthermore, it is possible to realize these goals without any modifications to existent automobiles or technical breakthroughs. (MegaRail is just such a system.) Such a system can be put in place at less cost than adding a single pair of freeway lanes. Because installation of such a system does not affect existent road surfaces or road use, it greatly increases capacity of existent rights of way. Because such a rail system operates as a toll system, it generates revenue that can be used to service revenue bonds used to fund construction. The taxpayer is not asked to pay for the system. Initial reaction of both the general public and public officials has been highly favorable to this approach. Because of this situation, it is politically realizable. Politically realizable is an essential feature of any practical system.
The author's paper should be characterized as one of those impossible dream papers that is not likely to be realized. It sounds great until you try to really make it work in a practical way. That is when the problems really begin!
It is time to get realistic with regard to solving our serious traffic and air pollution problems. We can not afford to wait for some future advanced technical development or count on vast expenditure of public funds. Technical breakthroughs are impossible to schedule or predict. Massive amounts of public funds from any level of government, including Uncle Sam, are simply not in the cards and can not be made available to solve the problem. Furthermore, the U.S. Federal Government is not likely to ever solve the problem because of sheer inertia!
Last modified: May 27, 2001