The pattern of city, suburban and township bus operation, established in the colonial and Apartheid eras, was severely disrupted by the eruption of minibus taxis in the late nineteen-eighties, but very little was done to revitalise these services until preparations were put in hand for the Soccer World Cup tournament staged in mid-2010.
These resulted in a number of Bus Rapid Transit, or BRT-related systems, which introduced new dimensional and mass parameters and a rethink on routing priorities to urban bus operation. In the long-distance and tourism arenas, limited numbers of highly sophisticated luxury coaches, many of which were fully imported, found their way into the local market.
In concert with other elements of the commercial vehicle industry, bus suppliers have been able to increasingly tap global product sources since the termination of stringent local content requirements in 1994.
Although this effectively eclipsed the indigenous bus bodybuilding industry, as it had been up to the 1980's, it has resulted in local operators being offered a vastly increased range of options in terms of vehicle layouts, technical specifications and even fuel types, when considering new acquisitions. The following comments trace the pattern of emerging trends in the global industry that are sure to make their way to South Africa in the years ahead.
A combination of global environmental concerns, and political instability in many oil-producing countries, has seen the increasing adoption of alternative fuels and propulsion systems as mass-produced options to the diesel-engined norm that applied, almost universally, prior to year 2000.
Although much popular opinion would still like to see a more permanent solution such as hydrogen-fuelled zero-emission vehicles sooner rather than later, practical considerations surrounding the handling and distribution of liquid hydrogen have dictated that the world must pass through several interim stages before this Holy Grail can be attained.
As things stand, the three broad technologies that have found increasingly widespread application in buses are alternative fuel internal combustion engines, hybrid drivelines, and all-electric vehicles. Each of these have numerous variations, including Compressed Natural Gas, Liquefied Natural Gas, ethanol, methanol, parallel or series hybrids, plug-in hybrids, range-extended electric vehicles, pure battery-electrics, and even trolleybuses, but their common mission is to reduce dependence on fossil fuels, and to release less harmful emissions into the atmosphere.
Most city and suburban buses operate within well-defined geographic areas, on fixed routes and schedules, which make them ideal candidates for alternative driveline applications. Their operational profile greatly facilitates the provision of specialised fuels and maintenance, making it possible to locate technical and logistic support at a limited number of fixed points.
This is even more apparent in BRT operation, where buses and bus trains use a dedicated right-of-way, which is, of necessity, a near-permanent arrangement. Inevitably, new technologies unearth new challenges, and these are more easily overcome when the vehicle is never any great distance from base.
The increasing use of individual wheel electric drive motors in series hybrid and all-electric applications have also greatly facilitated the building of ultra-low-floor buses, which were previously restricted by the proportions of their live drive axles.
Following a lengthy period when trolleybuses had become a lesser force in global urban passenger transport, this mode is currently showing signs of revival. Whereas hybrid vehicles, by definition, carry their own on-board power generating units, and plug-in electrics require heavy and space-occupying battery packs, trolleybuses offer a simpler no-emissions operational solution, with direct transmission of current from the overhead power supply to on-board traction motors.
This mode has most appeal in applications, such as BRT, where operational flexibility is not the major consideration, but it can also be combined with the other technologies to provide some degree of "off the wires" mobility where this is required.
