BUSINESS INTELLIGENCE and the butt of numerous disparaging remarks and commentary. The reality is that SANRAL saw the e-toll system as the solution to funding the very real need for road infrastructure, in an easy and efficient way. But before we discuss this, we need to have a little background as to why we even need money for roads, given the burden the taxpayer has in supporting a top-heavy government and a seething mass of poor.
Why maintenance?
While South Africa’ s roads can compare favourably with any developed country you would care to name, they require maintenance, more so after heavy rains when the infamous potholes appear in our city and suburban streets. And therein lies the crunch. Of the 750 000km of South African roads, only a mere 22 000km fall under SANRAL’ s responsibilities, and these are not those potholed roads in front of your house in downtown suburbia. The authority’ s mandate is national roads. Yet, this argument has been the cause célèbre for the e-Tag dodgers, citing poor urban road maintenance as an example of villain SANRAL’ s perceived negligence. Louw Kannemeyer, SANRAL’ s new engineering executive, appointed in November 2017, is impassioned when he speaks about this perception. He explains:“ If you go back into the history of SANRAL, you will see that we have what we call preventative maintenance. On a frequent cycle, we are trying to maintain the network [ of roads ] through periodic actions that keep the surface of the road waterproof. We are attempting to prevent the rapid deterioration of the national road network.” Kannemeyer explains that South African roads have a specific design to achieve the necessary waterproofing:“ The design of roads in South Africa is based on having a very thin waterproofing membrane at the surface.” Compared to Europe and the US, where this membrane averages about 100mm or more of waterproofing layer, South Africa has between 10 and 40mm. The engineer explains that this is largely because we are not an oil-producing country and that layer of waterproofing uses( imported) bitumen— a black viscous mixture of hydrocarbons obtained naturally or as a residue from petroleum distillation. Cost is an issue. He explains that over time, and for about the past 40 years,“ the bitumen layers have been substituted with good quality, natural gravel materials” to counter importing costs. Kannemeyer adds that this substitution has managed to reduce initial road construction outlay by between 30 and 50 %, depending on the location. He goes on to elaborate that, because the waterproofing layer is so thin( compared to overseas), when that layer cracks, water ingress occurs, undermining the granular layers beneath the tar, which soften and collapse, resulting in potholes if not repaired timeously. He emphasises that this is the reason that preventative maintenance is so crucial in South Africa. So, what is causing the extensive road damage?
Rail vs road freight
In South Africa, economic growth and the change to‘ just in time’ manufacturing and limited warehousing, results in the need for smaller more frequent deliveries, which favour road transport above rail. Since deregulation in 1988, the modal split has changed to road( 87 %) and rail( 13 %). The result is an increased number of heavy vehicle axles on roads, and since road pavements are designed for the number of heavy vehicle axles over, the lifespan( in years) decreases. According to Kannemeyer, the conception that our roads are damaged by heavy trucks hauling freight, as a result of poor or absent rail infrastructure, is not necessarily accurate. He comments:“ Worldwide, road freight patterns are the same, in terms of rail versus road,” he says. It is not peculiar that we use our roads so extensively for freight,
Kannemeyer assures, as the worldwide trend is to focus on cost efficiency:“ The ability to move your container on its own, receiving it on time, is quicker than loading it onto a slowmoving train. Even in Europe there are similar patterns— in fact, worse than ours. They have a 90 % road and 10 % rail ratio.” It is often remarked that our roads are not built for heavy loads, for transporting ore from the mines and timber from plantations, for example. Kannemeyer counters this observation:“ We don’ t design a road to last a certain number of calendar years. We design it for the traffic that we expect to move along the road during a specific number of calendar years,” he emphasises. He explains that when a road is built, the present amount of traffic along that stretch is considered, both heavy and light, and it is forecast how this will change over a given number of years, for example 20 years. From this, a number is calculated.“ In South Africa, for the pavement design, that number is called the equivalent standard axle: the equivalent number of standard axles that are expected to use that road during its lifespan. That could number in the millions, depending on how busy the road is,” he adds.“ That determines the kind of road pavement that needs to be constructed, to carry that traffic.” Kannemeyer explains that the preventative maintenance strategy works on an eight- to 12-year cycle.“ Every year, and at a maximum of two years, we assess the condition of our entire road network, in our two survey vehicles, equipped with 3-D cameras and lasers.” These cameras can detect a crack less than 1mm in width, while the vehicle travels between 80 and 100km / h over a distance of up to 600km per day, depending on travel and road conditions. That information assists SANRAL to monitor the progress of the development of cracks and optimise time maintenance intervention on the relevant road, which, he assures, takes place within 48 hours of an issue being detected. If a road has been designed with
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