Critique of the Paper by Steven Shladover Regarding the Problems and Potentials of Automated Highway Systems
by
Kirston Henderson, MegaRail Transportation Systems, Inc.
June, 2000
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!
Other Observations:
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