Light Transit

now called "Automated Guideway Transit" (AGT) or "Personal Rapid Transit" (PRT)

An attractive alternative to the automobile

The Modern Transit Society

by John Lambert, David Walworth, Al Spivak (MTS officers)

This article, written in the early 1970s, is still valid, although some terms are outdated. For updated information, see our Automated Guideway Transit page.


Among our primary community needs today is an improved transportation system with a better mix of light transit, heavy transit, and automobiles. Overemphasis on highways has led to a deterioration of our urban environment, inconsistent with the needs of the twentieth century.

Happily, there is acceptable alternative transportation for most of the trips which we take by automobile--alternatives which, in fact, are far less costly. Realization of this fact is essential to the stimulation of strong public demand--a demand which could overcome the powerful influences which have kept us locked into automobiles.

Certain basics must be understood in order to evaluate alternatives. First of all, it must be realized that there is nothing magical about automobiles and, given attractive, properly- priced transit, people will indeed use it for many of their trips. For example, about half the patrons of the Lindenwold rapid transit line linking Philadelphia with its New Jersey suburbs are ex- automobile drivers. Most commuters on New York, Philadelphia, Boston, Chicago and San Francisco suburban trains are auto owners who appreciate the advantages afforded by rail transit. The past desertion of transit in favor of automobiles is not proof of real preference, since transit and automobiles have never competed on bases which are economically and legally equitable.

A Viable Alternative to Driving

To compete with the auto, a transit system must offer reliable and continuous service at short intervals throughout the day and night. The service should be fast and comfortable, its operation should involve minimal intrusion upon the environment, and its charges to patrons should be diffused in the same manner as the per-trip costs of the automobile.

To facilitate understanding, it is interesting to consider a type of transportation with these attributes in common use today: the ordinary elevator. An elevator gives fast service with minimum risk to patrons and others in the area; it requires no operator, makes no noise of smog, and charges no fares. Passengers never consult a timetable--a mere button-push bringing prompt service and a quick ride to destination. A logical development would be the placement of elevator shafts in the horizontal position, so that they would be able to provide the same high-quality type of service between sections of a community. Such a development involves no unusual technological problems, since it is as easy to move a vehicle horizontally as vertically. Instead of a shaft, a narrow, inconspicuous beam, which the cars straddle, is the only guideway necessary. Such a beam can be placed above the curb-line of a street where the light poles are usually located, and it would support or enclose all of the wires, cables, street lamps, street signs, etc., which now festoon the landscape. Or, it can be placed on a median strip or between rows of trees. In some areas, it might be desirable to put the line beneath pavement or buildings, in a tunnel or roofed- over trench.

The equipment to provide a "horizontal elevator" transit service is already developed and available. It is often called "Light Transit", "Automated Transit" or "Personal Rapid Transit" (PRT). Some lines have been undergoing tests in Pittsburgh, Pennsylvania, at airports in Washington and Texas, and elsewhere, while others have been running for years at amusement parks and expositions. One example is the Swiss-built "Mini rail" system which has been in successful operation at the Montreal Exposition grounds since the year 1967. Here, automated electric cars run at close intervals along a network of slender overhead guideways. The cars are mounted on pneumatic tires and are virtually noiseless. Their automatic operation frees them from the need for individual drivers and provides a level of service and safety which cannot be achieved otherwise.

In an urban-suburban application, the guideway might be placed along streets which are spaced about half-a-mile apart in a checkerboard pattern, with the ends of the routes connected to create one or more continuous closed loops. On such a system, trains would traverse a number of different lines before returning to their point of origin. In this way, switches and route changes can be virtually eliminated, and an extremely simple, reliable and economical type of operation results. With stops possible at any point of intersection, a passenger could change from one line to another in order to set up any route he preferred. As with conventional elevators, stops would be made only when a patron pressed a button, so that even with the close station spacing, average speeds higher than those of street- borne traffic could be maintained. Closed-circuit television of speaker systems would connect cars and stations with operational headquarters to permit passengers to obtain information and to report any problems.

A variation of this concept of a fixed path closed loop is a system comprised of individual, small-capacity (two to six passengers) cars running at close intervals (perhaps ten seconds or less) along a guideway having sidings at each station, and routes so linked that cars could move directly from a passenger's point of origin to his destination. Cars would leave the fast-moving stream to enter a side track when a stop was to be made (signaled by a pushbutton or other command to the computer); otherwise, they continue along the main track without a halt. When a patron summons a car, the next vacant unit switches into his station. After he boards, it merges back into the mainstream and glides along appropriate routes under computer control until the passenger's destination is reached.

What About the Environment?

In both types of light transit systems operation is by central- station electric power, which is the least damaging to the environment, and which affords the greatest possible system efficiency. Also, the entire operation is along a reserved right-of- way, with no automobile or bus traffic interference--a fact which makes possible the automatic operation that is the key to success of this type of transportation. Only with automatic operation is it possible to provide high-frequency service throughout the day and night along a community-wide grid network that has many stations.

Cost of Such a System

Cost of Light Transit systems varies with particular equipment. Prices range from less than one million dollars per mile, including line, stations, cars, power equipment, controls and maintenance shops, up to $4 million per mile. Even the highest figures compare well with present-day highways, which in urban and suburban areas are costing from $8 million to $50 million per mile, and, with the large amount of land which such highways require, highways in these areas are not feasible. The comparison between costs of Light Transit and highways is even more striking when it is realized that the highway costs do not include vehicles; and that highways remove vast amounts of land from tax rolls while the modern Light Transit could operate along existing rights-of-way and take very little land. There are, of course, a great many other benefits having economic portent. For example, since one line of Light Transit can carry as many people as several freeway lanes, the smaller investment represented by transit produces far more people-moving capability. In addition, each automatic vehicle on the transit system provides service for many different patrons during the entire day, instead of wastefully taking up space in a parking lot when not needed by its owner, as do automobiles.

Why Not Use Buses?

At this point, it is appropriate to discuss buses, and the reasons why buses do not comprise a viable, attractive form of transportation to the extent necessary to displace the automobile. The major problem has already been mentioned: Dependence of buses upon drivers. Bus drivers in urban and suburban service are among the least productive of present-day labor. This results from the fact that buses operate at schedule speeds which usually average less than twelve miles per hour; bus occupancy in all but the largest cities is extremely low; and the driver earns not only his hourly wage, but also vacation and holiday pay, premium wages for overtime, sick pay, etc. Because of these factors, driver-labor represents some 80 to 85% of the total operating cost of a bus transportation system. This high expense, and the fact that the cost of drivers is directly related to the frequency of service provided, creates a powerful incentive not to run buses during periods of light patronage. Accordingly, bus lines offer very little, if any, service during off- peak hours, and areas dependent upon buses often have no public transportation service whatever during night hours, Sundays, etc. This lack of dependable, continuous service requires that families provide themselves with automobiles in order to assure mobility during the times when buses are not available. Possession of the auto, in turn, encourages people to get the greatest possible use out of it in order to justify its high fixed cost. This, in turn, creates an incentive to use the bus system as little as possible. This vicious cycle has resulted in the transportation crisis which exists in most urban areas today.

Other reasons why buses do not constitute a viable substitute for the automobile are their operation along congested city streets, their marginal riding comfort, and generally poor image. From the operator's viewpoint, buses suffer from high depreciation rates, limited carrying capacity, restricted schedule speed, susceptibility to traffic mishaps, and high insurance rates. For these reasons rejection of buses by the public cannot be construed as a negative attitude toward public transit in general. What is required is new and innovative transit, whose operating costs are low enough to allow full service on a continuous basis, including nights and weekends.

Paying for Transit

Another important element in converting many people from auto drivers into transit patrons is the manner of payment for the service rendered. Payment for automobile trips is on a deferred and diffused basis, in addition to which roads and streets are heavily subsidized from non-automobile taxes. The gasoline tax pays only a portion of the cost of these facilities, and there is no property-tax assessment against automobiles for the land taken by highways. Thus there is little distinguishable relationship between the trip taken in a car and the payment for that trip. Furthermore, the automobile's high ratio of fixed-to-variable costs makes the incremental, per-trip, price seem negligible. With public transit, on the other hand, costs are usually assessed directly against patrons, with a farebox or turnstile barrier to assure that each person pays directly for every trip. As a result, there is an immediate and obvious cost for using public transit--and one which multiplies when a man takes his family along with him. Hence, there is a built-in "price" incentive NOT to use public transit, even though its total, long-term cost is much less than that of using an automobile. This disparity must be corrected, and a payment arrangement instituted for mass transit which will provide a positive incentive for use of transit in lieu of the automobile. This can be accomplished in any of a number of different ways. The most obvious method is the total elimination of the fare, with the cost absorbed as a community need in the same way that the cost of the automobile's streets, traffic lights, patrolmen, etc., has been absorbed. It is easy to show that the total tax burden of building and maintaining a fare-free modern transit system would be less than the public tax burden now carried for streets and related auto needs. On top of this, of course, families would no longer be compelled to maintain fleets of automobiles, there would be great saving of taxable land which would otherwise be consumed by highways, air pollution would be significantly reduced, a new measure of safety would be realized, and our communities would once more belong to the people instead of to machines. So a totally fare-free public transit system has a great deal of merit in a society which has already dedicated itself to tax-supported transportation via roadways, airways and waterways.

A different approach would be to continue supporting public transit through charges against those using such service, but to halt all subsidies to the automobile. This can be accomplished by simply making it illegal to divert into road purposes any tax moneys not realized through direct assessments against automobiles. This would have the effect of keeping auto users aware of the true cost of their particular mode of conveyance, especially if an equitable property tax were assessed against autos to compensate the community for land taken by roads.

The Urban Environment

With reduction in dependence upon the auto, profound improvement would be made in our living environment. Suburbia, for example, could become clusters of homes set in park-like greens, not criss- crossed by streets. Alleys would care for deliveries, trash collection, and access to garages, and tension and noise would be greatly reduced. Grocers would certainly resume deliveries--a service which they used to perform as a matter of course. Most needs for personal mobility would be handled by modern systems of automated Light Transit--systems which have already been developed, and which but await people's awareness and political action for installation. Automobiles would resume their role as part of a transportation system--rather than being all of it.

What Can a Citizen Do?

New technologies to free us from domination by the automobile are feasible and ready for installation now, and their cost would be less than we're now paying for autos and roads. However, they will not become available automatically, because there are powerful forces whose empires and incomes depend upon undiminished auto use and unending road construction. These people have held sway for so long, and have played such a dominant role in molding public opinion and shaping political structures, that strong effort is required to promote transport progress. Taxing structures favor highway construction and, in many cases, these structures are seated deeply in state constitutions. These favorable arrangements, in turn, are jealously and carefully guarded, so that the public has little opportunity to learn about them and to adjust them to suit today's needs. In many cases, confusing information has been spread concerning automobiles and alternative public transit, so that citizens are unaware of the possibilities that modern transit offers. In certain cases, municipal, county and state policies with respect to transportation are set by officials who have commercial interests in the building of highways. At times they show a condescending acceptance of public transit--provided such transit is furnished by buses, which will use the highways and justify further road expansion.

In such an ambient, it is no wonder that alternatives to the auto have been slow in arriving. However, it has been said that "Nothing can stop an idea whose time has come", which applies very well to the coming of modern transit. Strong action by determined citizens will be necessary, along the following lines:

1. Learn what the auto and its roads really cost your community. Find out about the hidden subsidies--how much property tax would have been collected on the land lost beneath highways, how much "free" parking really adds to the price of merchandise and services, how much your town spends for road maintenance, traffic signals, crime prevention and traffic courts.

2. Find out what local committees exist to determine the direction of transit progress; seek them out, and assert your position with respect to this vital facet of life. If consideration of transit's future is dominated by highway-oriented officials, have such officials replaced by qualified transit people.

3. Watch actions of your State Legislature and support measures to free automobile fuel taxes for general transit use. A great many people drive only because there is no other way to get about and it certainly isn't fair to force them to contribute to more highways.

4. Insist that your State Government eliminate the Highway Department, with its necessarily restricted interest, and replace it with a broad-based department having general transportation responsibility.

5. Ask your congressmen to transform the Federal Highway Trust Fund into a Transportation Fund, so that some federal tax revenue can be made available for transit, without an increase in taxes. Federal funds for transit have been very meager, compared to funds for highways.

6. Support organizations dedicated to promotion of alternatives to the automobile. Join the Modern Transit Society and help it work for installation of attractive transit in your area.

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