10 July 2013
BRT has become a buzzword when talking about creative transport solutions. However, it is only under very specific conditions that BRT provides the one-size-fits-all answer to a city’s needs.
Worldwide experience of BRT implementation is often guided by success stories in South America. As a rule, these successful cities had high population densities, an established middle class and were historically unserviced by rail.
MyCiTi was initially designed on the highly successful Bogotá model, which sets itself apart by its unique set of characteristics. Firstly, Bogotá has a high population density, with an average of 3912 persons per square kilometre. Its trunk route took on a looped “start to end” shape, linking three natural work destinations to each other. Having many destinations on the same route meant that up to three fares could be sold per seat for each peak hour journey as passengers board and depart more frequently. It was through this model of consistent high demand and passenger turnover along the entire length of the route that the Bogotá system was able to achieve operational efficiency – a case when incomes cover expenses, and no subsidy is required. Indeed, this ability to function without subsidies is one of the main reasons the BRT concept gained such traction globally.
However, operational efficiency with BRT systems is an exception rather than the norm, and it is vitally important to realise that this feat was only achieved through the combination of the factors listed above.
In contrast, Cape Town had an average population density in 2007 of 1424 persons per km2 – roughly 36% of what it is in Bogota. It is characterised by a highly used rail network (if not a world-class one), and urban sprawl – meaning that the various destinations for the Cape Town working class are more spread out than in Bogotá.
Users of public transport are a relatively poor population group, with Golden Arrow Bus Services (Gabs) reporting in its latest passenger survey that 66% of its 200 000 daily passengers earned below R3000 per month, and 84% below R5000.
Furthermore, in line with the Bogotá model, the concept in Cape Town was to link three nodes of economic potential – namely Atlantis, Epping and Paarden Eiland, and the Cape Town CBD. However, the investment into developing these nodes failed to materialise, and the trunk route failed to extend to Atlantis because of several complications with establishing vehicle operating companies.
The route was also restricted geographically to be straight, rather than looped, which limited peak hour demand to only one direction (rather than both directions simultaneously).
As a result, buses moving against the peak flow remain largely empty. Moreover, average trip distances at 17km are more than double the Bogotá standard, meaning higher costs per passenger per trip. The lack of a variety of nodal destinations has meant that passenger turnover on route is low, and each bus is only filled once per trip.
The point here is that BRT is extremely expensive – something that the City has discovered through implementation. Whilst it might produce a very welcome improvement to current service levels, one has to ask whether it was what Cape Town truly needed. Only in very specific circumstances is BRT the “be all and end all” solution, and Cape Town has a highly unique set of urban features. The benchmarking of the West Coast trunk route on the Bogotá model was fundamentally flawed in that the developmental needs of the city did not mimic those that faced Bogotá in any way.
It is important to recognise the limitations of best practice models. Best practice might not be useful in achieving recommendations for a “one-size-fits-all” solution, but are often useful when being used to establish a set of base conditions and standards required for different kinds of services. In this sense, best practice models provide an invaluable set of guidelines against which to measure the characteristics of a route or region.
When it comes to BRT systems, various global studies offer insights into the kind of demand, population density, and public transport usership that would make it the ideal option for planners. As shown above, Cape Town has very different characteristics to Bogotá. In the same breath, this does not mean that BRT, or a similar kind of service, cannot be an effective option.
The International Association of Public Transport (UITP) established basic guidelines to show the levels of demand needed to justify the rollout of different kinds of bus services. What is interesting about this blueprint is that it shows that BRT can be effective in Cape Town if the City achieves one of its main objectives of converting non-public transport users into users. As it is currently operating, MyCiTi requires a much larger subsidy (7 times larger according to Gabs) per passenger. However, if it can double (or even triple) the demand for the service, this subsidy per passenger would be reduced drastically.
The West Coast trunk route falls into the category of a BRT with Articulated Busses, as it makes use of lane exclusivity, and fully enclosed stations positioned in the median of the road. The lower passenger demand threshold for such a service is around double what is currently forecast. Whilst none of the proposed routes indicate levels of demand needed for this kind of service, there is hope that an increase in marketing, exposure and confidence in the service can at least somewhat offset this shortfall.
Two further studies1 relate the usership and population densities along proposed BRT routes needed for a sustainable service. The first calculates that BRT routes need a minimum of 625 daily boarding passengers per kilometre. Thus, the 17km MyCiTi trunk route would require around 10 600 boarding passengers per day. The 2012 Transport Survey revealed that only 2 458 passengers used MyCiTi to travel into the City Centre per day (Cape Town Partnership, 2012), and the entire West Coast trunk-route carried only 6028 passengers per day (GABS, 2011). These numbers again point to an unsustainable service if things do not change.
The second study calculates that to justify the BRT-style enclosed stations that have been used along the trunk route, there is a need for at least 1600 boarding passengers that reside within an 800m radius of each station. Considering Cape Town’s average population density, this is not viable. Cape Town is unique in that the residential areas of high-density demand are often separated from destination by lengthy distances of low-density demand. As a result, the decision to use exclusive BRT technology throughout the first phases of the MyCiTi rollout was perhaps a poor decision, and many of the expensively built stations remain largely unused throughout the day.
On an encouraging note, the City has displayed a willingness to defect from the original plan, and is now planning to build exclusive stations only at points of high-density demand. The vehicles used will also change, and will have the kind of flexibility required for different kinds of boarding.
The Cape Chamber of Commerce believes that as the infrastructure built in the first phase did not allow for “facility piggybacking” (i.e. existing transport modes were not able to use it too), the City’s strategy failed to meet its objective of achieving an integrated service. This, they feel was a massive oversight, and that taxis and formal busses were excluded from the benefits, and ultimately made to be worse off than before.
In this light, the City’s decisions to move away from their original plans are extremely positive, and it hopefully signals a movement towards a more integrated and collaborative service – one that more carefully includes the needs of taxis and formal busses. This kind of behavioural shift is vital if the City wants to avoid past mistakes and build a BRT system that serves to address the needs of Cape Town, rather than build a BRT system to which Cape Town is forced to adapt.
These are studies completed by Clay Martin in 2011 and 2012, focussing on the demand densities necessary for BRT. ↩