Lowering the floor

Low-entry buses in South Africa are slowly becoming the “new normal” – and not before time.

Road public transportation systems, specifically buses, formerly made use of a high-level ladder chassis, which precluded the possibility of low-entry or low-floor arrangements. This was largely based on the misconception that the road infrastructure would not allow the successful operation of low-floor vehicles due to the suggested problems with the vertical curve geometry.

Of course, roads in rural areas are unsurfaced, but most roads in urban areas have been built with macadamised pavement surfaces, which lend themselves to the new technology.

The first notional introduction of a fixed route, low-entry bus service was contemplated by a bus operator in Cape Town in 2000. It was spurred largely by initiatives by the Volvo Bus Company, which introduced the idea of low-entry buses in the country.

At the 20th South African Transport Conference in July 2001, delegates reported this encouraging response:

“Passenger reaction to the bus was overwhelmingly positive and on-board survey results revealed that 48 percent of passengers waited specifically for this particular bus and 11 percent of passengers were individuals who did not regularly use public transport, but who started doing so when the low-floor bus was introduced on the route.”

When the City of Johannesburg started developing its integrated rapid public transport network (IRPTN), it sought input from a range of international agencies. Its bus rapid transport system (BRT), known as the Rea Vaya, opted for a high-floor modality, using bus bodies manufactured on a high-level ladder chassis. This design influenced the City of Cape Town’s own MyCiTi component of its IRPTN. The motivation for this high-floor modality was also influenced by systems overseas, particularly in Brazil, where stair access and platform lifts were in operation to enable access to the elevated platforms in the bus stations.

In South Africa, though, the infrastructure is different: platform lifts or hoists are usually not in place or, where they are, they introduce other challenges. Very long ramps into the bus stations have been constructed for access, which are at gradients that exceed the minimum internationally accepted gradients. The plan format or footprint of a bus station, especially when it is located in the median island, is fundamentally longitudinal with an access ramp on either side. This requires ramps of the order of 17 m long to achieve the required gradient and provide for a landing at the midpoint, a collective 30 m at each bus station – which is clearly not workable. (The application of well-established Universal Design principles would have identified the functional deficiencies at the outset of the design and development of these initial services.)

And so, the decision by Rea Vaya to change to low-entry vehicles for the next phase of the service is most welcome. The IRTN in the City of George, the IRPTN in Tshwane and the Ekurhuleni Metropolitan Municipality have all opted for low-entry versions.

 

By Phillip Thompson, IDC Consultants Cape Town

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