The Federal Department of Transportation's Role in the Development of Automated Peoplemovers in the 1970s: Some Historical Recollections

The following excerpt is  from the first part of an article by Charles Broxmeyer entitled "Level of Service in Large-Scale Automated Transit Systems", published in Transportation Planning and Technology, 1990, Vol. 14, pp 287-308.  Mr. Broxmeyer was Deputy Associate Administration for Management and Demonstrations in the Urban Mass Transportation Administration of the US Department of Transportation.  Posted with permission from TP&T.


Automated transit systems, wherein moderate-sized, driverless, vehicles traverse elevated guideways, are generally classified in accordance with two primary characteristics—minimum headway regime and type of station (offline or online). Minimum headway, the shortest time between passage of two vehicles past a fixed point, is a critical determinant of the type of service that can be offered, the scale of the guideway that can be emplaced, and the type of control system that can be employed to prevent collisions between vehicles.

The automated transit systems that have been installed in various airports (with the exception of the Dallas/Fort Worth Airport), and in the cities of Kobe, Osaka, Miami, Detroit, Lille and Vancouver, have online stations and run at headways in excess of 60 seconds. Two systems in the United States, the Morgantown system and the Dallas/Fort Worth system, have offline stations and operate at minimum headways of 15 seconds and 18 seconds respectively.

Fifteen seconds is generally considered the lower headway limit for systems employing "block" control systems, wherein safe vehicle separation is assured through interaction between vehicles and instrumentation located at discrete intervals along the right-of-way. Block control systems are feasible at shorter headways, but costs mount rapidly as headways decrease.

During the early part of the Seventies, there was much interest in shorter-headway transit systems, as a possible means of effecting radical change in the type of transit service available in cities. Citywide guideway networks were envisioned, and advocates of these systems recommended development of new control and vehicle systems capable of operating at headways substantially shorter than the Morgantown headway. In France,  Germany and Japan, efforts were initiated to develop systems capable of operating at headways as low as one-half to one second.

In the United States, the Department of Transportation (DOT) initiated development of a three-second headway automated transportation system. These developments received substantial resources from their respective governments and, in France, Germany and Japan, prototype systems were developed. However all these developments were ultimately abandoned.

Planning for the US effort was initiated in 1972 and the first contracts were awarded in early 1975. The program, originally planned for execution in four years, continued for ten years, experiencing during this period a long series of stretchouts, delays, reappraisals, scope modifications and funding revisions. In 1980, the Department of Transportation rescinded its request for funds for the development, but Congress insisted that the program proceed. A deadlock on this issue, between Congress and the Department, persisted until 1984 when congressional support was finally withdrawn.

In the middle Seventies, priorities within the DOT shifted from development of new short headway systems to installation, in cities, of small systems, consisting of several miles of already developed people movers designed to operate at conventional headways. Proposals for such installations were solicited from city governments and a program of substantial scope took shape. The short headway work was de-emphasized but was not eliminated. The shift in emphasis of the DOT program—from a development program aimed at a new capability with potential for serving large cities, to an installation program for systems with substantially lower passenger-carrying capability than rapid rail— led to a growing perception that substantial improvements in urban transportation through new technical means were not possible, although, in fact, no new information of either an experimental or theoretical nature had been developed to illuminate this question.

During this period there was much debate on the merit (or lack of merit) of systems operating in the various headway regimes. An Office of Technology Assessment (OTA) report in 1975 stated that "No clear urban transportation need is apparent for the short three-second headway performance specified for the (DOT) program." A subsequent OTA report in 1980 found otherwise. Rapid rail spokesmen insisted that efforts in the direction of short headway systems were a waste of government resources.

Advocates of headways in the fractional-second range were strongly opposed to the DOT's short headway project, insisting that it was too conservative to lead to effective improvements in public transportation. Advocates of people movers that operated at rail system headways stated that improvements in automation were sufficient, without reaching for exotic new control technologies capable of moving vehicles at short headways. In 1981, priorities within the DOT changed again. The people mover installation program was discontinued. However installations already started in Detroit and Miami were completed. The development program continued until 1984, as already noted. By this time, Congress had assembled, and was earmarking funds for a long list of fixed-guideway installations of its own choosing—all of the conventional type.

Last modified: September 25, 2007