|Light Rail Transit Association - UK Development Group
FACT SHEET No 124
The question is increasingly being asked by many transit planners and decision makers following the recent "half-price tramway" experiments in the French city of Nancy. Their new guided trolley bus, supported on rubber tyres but guided by a centre rail, commenced full public service during February 2001 but had its licence suspended a month later due to two accidents associated with stability, one with injury to passengers (2).
THEY HAVE SO FAR MADE LITTLE IMPACT (3).
The first experiment in Britain with guided bus operation was about 15 years ago in Birmingham and from a technical point of view appeared as a success. Bus deregulation though brought with it some unexpected operational problems, one of which was the location of passenger stops in relation to competing buses not using the guideway. The next application some years later was in Ipswich with a very short section of guideway which appeared to be more of a traffic control measure than steering aid.
Many places in Britain have already shown an interest, often following up from an aggressive campaign by commercial forces suggesting tram kudos but at only half the price. To a certain extent, the project along Scott Hall Road in Leeds appears to fit this criterion, and being well below commercial justification for light rail could well be the perfect test-bed for guided bus. These same guided bus services also circulate in amongst ordinary bus services in the city centre and tend to perpetuate some of the known faults associated with intense bus operation. About 3km have to be covered from the central area before the bus can enter its first guideway, actually a series of short lengths that make up about 15% of its route. A true cost comparison with light rail operation is difficult to assess because of some major operational differences. Light rail for instance includes the vehicles as part of the infrastructure funding whereas a guided bus route does not.
"SEEN AS A POOR MAN'S TRAMWAY" (4).
With a nationwide desire to upgrade bus services, there is a constant search for traffic corridors with patronage projections just below justification for some form of light rail. Scott Hall Road may well have fitted this criterion but the second corridor, still under construction in York Road, has a particularly busy patronage flow, and a "Mannheim" type of mixed operation (tram and bus) may be justified. Although only for a short length in Mannheim, the principle is the same.
When producing a cost assessment, the completely different operating techniques tend to produce a clouded picture which often hides the closeness of light rail cost in relation to guided bus. Research by Professor Carmen Haus-Klau (of Wuppertal University for the then DETR) argued that whilst bus-based schemes may be cheaper, the cost of the two modes is much nearer than is often assumed. Added to this though is the vital factor that light rail's operating costs are usually lower than for bus operation (5). Probably justifying a stronger acceptance in UK of light rail, Professor Carmen Haus-Klau described current guided bus operation as "terrible, terrible, terrible systems". Kerb Guided Busways are unattractive to look at, the benefits can largely be achieved with conventional bus lanes, and no one else is building them except Britain.
FACTORS BEHIND NANCY's BRT DEBACLE
As mentioned earlier, Nancy has exposed some of the "pitfalls" of operating a "half-price tramway" using guidewheels onto a guidance rail in the middle of the bus's paveway. This system, marketed by a Canadian company and called TVR (Transport sur Voie Reservé) is regarded as one of the most ambitious high-tech BRT (Bus Rapid Transit) installations in the world. In operational mode, a pair of in-line small double-flanged wheels is held down against the central rail by hydraulic force. Nancy's initial TVR line cost about USD9.6m/km (excluding vehicles) which is much lower than a typical US high speed interurban style light rail system but surprisingly close to a Portland-type streetcar system at USD11.2m/km. Although kerb guided buses are capable of achieving higher speeds than those that use a centre rail, they have problems at intersections because of a need for a 'funnel' at each end to collect the guidance wheels for proper alignment. The flush arrangement was probably the deciding factor for Nancy. Another cost advantage for BRT is that the paving costs on public roads are not always allocated to the bus's infrastructure budget. Another BRT gain, of an operational nature, is an ability to negotiate 13% grades. (The Supertrams in Sheffield are designed to negotiate a 10% grade). A claim of a 30-year life for the guided bus cannot at this stage be verified but it does seem to be somewhat ambitious. Multiple-unit operation with Nancy's moderate passenger loadings is unlikely to be an issue but with the impracticality of operating BRT in tandem, it could be an influencing factor elsewhere.
RAPID TRANSIT FOR THE AUTOMOBILE AGE (6).
Ottawa, Canada's capital, opened its first busway in 1983, chosen because in a light rail and busway comparison the latter was shown to be 30% cheaper to build and 20% cheaper to operate. Busways would offer a higher level of service because of the reduced need to transfer. It was claimed in a 1993 report that busways would remain the key to transit approach for the foreseeable future and their success had ensured their continued expansion. Under the heading of "Myths", a T2000 report (7) paints a very different picture as an answer to the flow of inquiries seeking help in the wake of claims advanced by the world-roving advocates of "cloning" Ottawa's busway around the globe.
A brief history: Ottawa's well-maintained tramway system was sold for scrap in 1959 to pay for a fleet of buses. The Mayor, defeated in an ensuing election, managed to get the trams off the streets to make them safer for the automobile. The busway was proposed with the aim of achieving 95m passengers per year by 1991 although the actual figures turned out to be 71m per year by 1995. Approved in 1981, costs over a 5-year period had escalated by 400% and would have been even higher if the proposed downtown bus tunnels had gone ahead.
The current position, described in a 1997 report, reveals a change in emphasis away from bus construction to bus priority at junctions. A 40km diesel light rail transit system using underused railway tracks is also recommended and the new Council Chairman is talking of providing electric light rail over converted busways.
Events in both Nancy and Ottawa have demonstrated that although a bus is an important part of any transit system, its primary function falls into a feeder role leaving the principal routes for light rail operation. Any move to "buck the trend" by throwing money at problems is a recipe for a future heavy tax burden.