In the 1980s, the general consensus among transportation specialists was that trolleybuses are and should be viable contenders in the modal spectrum. They were seen as fitting in between light rail transit and regular buses, particularly for midsize cities (population 250,000 to 5,000). It was acknowledged that higher capital costs were involved than for buses, but it was estimated that with high intensity use this expense could be readily absorbed. The construction of any rail line, of course is more expensive still. The benign environmental characteristics were given much weight. Every time one of the existing trolleybus systems acquired new vehicles, a rebirth of the mode was expected. It did not quite work out that way. Basically, trolleybuses provide a service not much different than regular buses, but the systems are more expensive to implement and are constrained by the infrastructure.

In the process of preparing dozens of transportation studies for whole systems or specific corridor in American communities, trolleybuses have been included frequently as one of the possible modal choices. The final decisions, with only two exceptions, have been that this mode is not suitable for regular transit service under normal conditions today. Since the benefits of air quality improvement at the scale of regions is not a dominant variable in the evaluation equation, the determining factor has usually been the local agency’s economic calculations related to the purchase, operation/maintenance, and fuelling of vehicles. In a number of instances where electrical power has been especially accessible, the analyses have shown a reasonably competitive situation – except that the ever-widening gap in rolling stock price has knocked trolleybuses out of contention.

Thus, trolleybuses remain a mode for special conditions: steep hills, unventilated spaces, or communities with a singular commitment to air quality or historical image. Two recent major efforts in the United States and one in Brazil illustrate this contemporary situation.

Seattle

Seattle, which has a long history of trolleybus use, reconfirmed its commitment to this mode in 1977 to 1979, when it closed down the entire system for refurbishment. The hilly terrain and the affection of local residents and officials for trolleybuses are significant factors in this community. The city extended the physical network and purchased a new fleet of 109 vehicles. In 1987, additional 46 articulated M.A.N.. units were placed into service.

A downtown transit plan was also started in 1978 to streamline the city’s public service operations. The decision was soon reached to build a transit tunnel that would provide direct access to major destination points and remove many vehicles from surface streets. City and suburban service routes would be channelled through this facility; later conversion to light rail transit could be provided for. Diesel buses in the tunnel would require tall ventilation towers, and “pure” trolleybuses would not be able to operate along several of the limited access highways that are parts of the service network. After much discussion, the logical choice in 1985 was dual-mode rolling stock, admittedly rather complex vehicles, but already in use for years in Esslingen, Germany, Nancy, France, and elsewhere. Bids were received from European manufacturers, and Breda Construzioni Ferroviarie was selected – 60-foot articulated vehicles with 66 seats and three doors, propelled by a diesel engine and an electric motor fed by retractable rooftop poles. Each unit cost $430,000 in 1986, and deliveries of the 236 vehicles started in 1989. Various parts and components came from different countries.

The L-shaped tunnel was opened in 1990; it is 1.3 mi (2.1 km) long and runs under Third Avenue and Pine Street. There are five underground stations with multiple berths, bypass lanes, mezzanines, convenient pedestrian access from the street, and artwork. The platforms are 380 ft (116m) long and 13 to 15 ft (4.0 to 4.6m) wide. Travel for passengers on buses within the downtown area is free, but the tunnel is closed on weekends. Before the opening of the facility, it took up to 30 minutes to cross downtown on the surface; the tunnel path now consumes 8 minutes. Best results are achieved when buses are moved in platoons through the tunnel.

Boston

Boston has not given up on trolleybuses either and has found a new application for them. This is the so-called silver line that will eventually connect Roxbury to Logan Airport, planned as a replacement for the pending removal of the Orange Line of the metro. The original intention was to place trolleybuses on Washington Avenue, but this met with opposition from members of the community, who demanded light rail service. Buses propelled by natural gas on reserved lanes were opposed as well, and therefore the compromise reached in 1996 was a dual-mode system with the potential for the conversion of lanes later to light-rail transit. This became just about mandatory because the route was to be extended via several tunnels past South Station, through South Boston to Logan Airport.

Sao Paolo

It is appropriate to conclude this review of contemporary trolleybus projects by referring to the effort now under way in Sao Paulo, Brazil. In addition to the rather elaborate transit networks that service this very large urban agglomeration, a new tracked trolleybus route – the Fura Fila is being developed. The vehicle design is based on the double-articulated Volvo model used in Curitiba (four axles, 25m [82 ft] long, 270 passengers), but is equipped with O-Bahn-type horizontal guide wheels. High platforms will be used on a grade-separated busway, much of it elevated so that it can be added to the already built-up districts. The first line will run from the centre of the city to the residential areas to the south-east; there are plans for a very extensive network and a large fleet of these special vehicles.

The governing factors that led to this choice are that Brazil already had extensive experience with trolleybuses, that petroleum fuel conservation and air quality upgrading are concerns of national policy, that all the necessary elements and vehicles can be produced within the country, and that the comparative costs are most favourable. Their estimates show that the busway will cost U.S. $15 million per kilometre, while a light rail transit route would cost U.S. $40 million and a full subway U.S $100 million per kilometre. This is a project that may very well be a crucial test case for trolleybuses anywhere in the foreseeable future.