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Computer Controlled Cars
Computer Science Department
Stanford, CA 94305
JulAugSepOctNovDec , :< 10 0
This article is originally from approximately 1968, but was probably
revised in the 1970s.
There have been a number of proposals for automatic control
of cars. Mostly, they have involved simple servo-mechanisms that
sense a cable buried in the roadway and some other mechanism for
sensing the distance of the car ahead. Such a scheme was studied at
RCA at the instigation of Zworykin, but the work was eventually
In science fiction, systems in which a single computer
controls all the cars in a wide area have been depicted but without
telling how the system would actually work.
We are also proposing the computer control of cars. Our
system requires a computer in the car equipped with television camera
input that uses the same visual input available to the human driver.
Essentially, we are proposing an automatic chauffeur. Our goal is a
system with the following qualities:
- The user enters the destination with a keyboard, and the
car drives him there. Other commands include: change destination,
stop at that rest room or restaurant, go slow, go at emergency speed.
- The user need not be a driver and need not even accompany
the car. This would permit children, old people, and the blind
greater personal freedom. It also permits a husband to be driven to
work, then send the car home for his wife's use, and permits her to
send it back for him at the end of the day. The car can be sent for
servicing or to a store where a telephone ordered purchase will be
put in it. If there is a suitable telephone system, the car can
deliver a user to a place where there is no parking, go away and
park, and return when summoned. Thus, the system is to have almost
all of the capabilities of a chauffeur.
- In contrast to a system based on a central computer, the
proposed system will be of advantage to the first person who buys
one, whether anyone else has it or not. It will require no change in
existing roads, but will be able to take orders from traffic control
computers when they are installed. When freeway lanes can be
dedicated to computer controlled cars they will multiply the capacity
of existing freeways by permitting 80 mile per hour bumper-to-bumper
traffic with greater safety than we have at present. Since the
system is a product and not a public utility, competition among
suppliers will be possible.
- A key goal is to achieve greater safety than we have at
present. A fivefold reduction in fatalities is probably required to
make the system acceptable. Much better is possible since humans
really are rather bad drivers, but complete safety cannot be
Now we shall consider the problems that have to be solved in
order to realize the system.
- Performance of the computer, cameras, and associated
electronics. Present computers seem to be fast enough and to have enough
memory for the job. However, commercial computers of the required
performance are too big. We envisage that a computer of about the
power of the Digital Equipment PDP-10 will be required. Military
versions of similar computers have volumes of one or two cubic feet,
but the requirements for memory and secondary storage would be
difficult to meet in a reasonable volume at present. However, the
development of more compact computers and other electronic circuitry
is proceeding at a rate that makes achieving the required compactness
not the pacing item. Some improvements in the performance and
compactness of television cameras is also required, but it is not yet
clear what these requirements are.
- Cost of the computer and other electronics. At present
prices, a computer capable of controlling a car
but containable only in a large van would cost $400,000 to $800,000.
A few thousand dollars worth of other electronics would be required.
Ten years should bring the cost down by a factor of ten. Mass
production would give another factor of three. This would permit the
system to be available as a luxury item. Another five to ten years
might be required before computer control would only double the price
of the car. These estimates must be regarded as guesses.
- Reliability of the computer and other electronics.
We can attempt to compute the required reliability by
demanding that present traffic fatalities be reduced to a fifth the
present number, i.e. to 10,000 per year, and by allocating only half
of these fatalities to unreliability of the electronics. This
further depends on the fraction of failures that lead to fatality
which can be kept quite low by having the computer check its health
and that of the electronics every tenth of a second, giving it
programs for dealing with partial failures, and providing a ``dead man
switch'' for stopping the car if the computer fails to reassure it
every tenth second. There are many possibilities in this direction
and the expenditure of much cleverness is called for. The reader is
advised against using his unaided intuition to estimate the results.
Nevertheless, present computer failure rates would not be acceptable
even if they never led to accident simply because of the
inconvenience. We estimate that an improvement of 1000 in
mean-time-between-failures is required. Rapid progress is being
made in this field, and we expect that ten to fifteen years normal
progress of the computer field will give the required result.
- Performance of the driving programs.
Developing the required computer programs is the most
difficult of the required tasks; it will probably take the longest
time; and the amount of time required is very difficult to predict.
Work on computer control of vehicles has started at the Stanford
University Artificial Intelligence Project. An experimental vehicle
has been equipped with a television camera and connected to the
computer with a two-*way TV and radio link. A simple program to
guide the vehicle to follow a white line like that in a road has been
successfully checked out, and programs for determining the course of
the road and detecting cars and other obstacles are being developed.
However, before computer controlled cars become a reality a much
larger scale effort will have to be made.
The nature and extent of this effort are not easy to forsee
yet. We are far from having exhausted the possibilities of our
present equipment, but eventually the radio link to the computer will
have to be replaced by a computer in the vehicle, and television
equipment capable of seeing better into shadows in the presence of
bright areas will be required. We need to be able to identify many
different types of objects on the road such as: persons, vehicles,
animals, traffic police, shadows, pieces of paper, cardboard boxes,
objects that have dropped from vehicles, traffic signs and other
signals, intersections, house numbers, and other information required
for navigation. It will have to be equipped with programs to
recognize and deal with a variety of emergency conditions. It will
surely be possible to make it better at this than humans since its
attention won't lapse, it can sense the mechanical condition of the
car continuously, and it can look to the side, underneath the car,
and behind every second.
The most intricate single problem is the visual pattern
After the required performance is demonstrated and before the
system can be trusted without a human driver an extensive testing
program is required. To demonstrate that the system is five times
safer than a human driver approximately 25,000 automobile years will
be required. This might be reduced somewhat by concentrating testing
on situations in which humans make most of their fatal mistakes, but
we would still need to be sure that situations in which the program
made fatal blunders peculiar to the computer system were rare enough.
Developments in the mathematical theory of computation may permit
getting rid of ordinary programming errors and proving that they are
absent, but possible inadequacies in the algorithms themselves can
only be obviated by testing.
- Public acceptance. Automobiles without
qualified human drivers will require
changes in the law. Fortunately, testing such systems with a driver
present to take over if necessary does not. Moreover, computer driven
cars will not be able to obey oral instructions from policemen , so a
digital system will have to be developed. A general resistance to
technological innovation on the part of the literary culture will
have to be overcome, but it seems to me that after the test phase the
advantages will be clear enough so that this will not be difficult.
- Support for research and development.
The development of computer controlled cars will cost
hundreds of milliions of dollars. A computer program capable of
reliably taking care of all the contingencies that can arise in
driving a car will have to be more complex than any ever written, and
adequate testing will require a complex organization. Fortunately,
The commitment of large amounts of money will be required only after
spectacular though unreliable performance will have been
demonstrated. So far as I know, the Stanford Artificial Intelligence
Project is the only organization now working on computer control of a
vehicle using vision. This work is part of a basic research project
on artificial intelligence supported by the Department of Defense.
Even at the present stage of the work, other projects are needed to
secure an adequate diversity of approach. While considerable
additional progress will certainly be made with the present support,
even a prototype will require more money than is now available.
Fortunately, this problem is within the jurisdiction of the
Department of Transportation. The automobile companies and the
computer companies also might be expected to help, but their past
record of seeing beyond the ends of their noses is not encouraging.
Because the programming is the pacing item, more support at this time
will hasten the day when computer control of cars is achieved, but
the possibilities will be much more obvious in five years with the
advances in hardware and programming that are already taking place
for other reasons.
Finally, we would like to deal with some arguments that might
be raised against supporting research aimed at computer controlled
- Cars must be done away with because they produce smog,
require too much space, and use up too much natural resources.
We believe the smog devices will eventually be made to work
well, or if not, another form of propulsion can be found. Computer
controlled cars will require less space than equivalent present cars
because they can go faster and closer together on streets, roads and
freeways, because they can park at a distance from a place where they
discharge passengers, and because a computer driven car can be shared
more easily than a conventional car. If hydrocarbon fuel runs out
and is still required for cars, then with nuclear energy, the burning
reaction can be driven backwards and fuel synthesized from carbon
dioxide and water.
- A simpler scheme of automatic control is preferable.
The buried cable and other simple schemes do not increase
human freedom and convenience. They only permit us to use the
freeways a bit more efficiently. Because of their inability to
detect dogs, children, potholes, and objects that have fallen from
trucks they may require unrealizable control of access to the highway
in order to achieve safety.
- Some form of automated mass transportation is obviously
better. The automobile can go point to point in areas of both low and
high density. We believe that these advantages should not and will
not voluntarily be given up. We favor the development of improved
mass transportation, but predict that the automobile will be given up
only for something that works better in all ways such as an
individual computer controlled flying machine capable of point to
Next: Inside the Computer Controlled
Fri Mar 29 12:05:08 PST 1996