Dualisation: The case for and against
A number of road crashes can be attributed to dangerous overtaking due to poor judgment by drivers at high speeds. The issue is then not to dualise the whole road, but rather to introduce strategic overtaking lanes only at specific road rises, because the climbing gradients slow down heavy traffic, which should then yield to the slow lane to allow impatient drivers to pass without killing anyone.
EXPLAIN to me again why the man on the street gets super-excited about the topic of dualisation of Beitbridge-Chirundu regional trunk road? I get it that people can ululate about the concept of a multi-lane road criss-crossing their neighbourhood. I get it too that whichever politician owning such a project will score on popularity. But let us get a few issues into correct perspective. Is it necessary? Is it priority? Who are the intended beneficiaries? What engineering justification has driven it?
Who is calling for it? Capacity demand or Honourable Minister?
Who is making most noise demanding dualisation to be effected? Is it the cross-border trader from South Africa to Zambia? Or is it the ordinary citizen of Mutare, Gweru, Kwekwe or Bulawayo? How much of the motoring public does this interest group represent? Is it higher than the suburban driver and passengers navigating on potholed streets, commuting from home to work daily?
In the past this call for dualisation has been spearheaded more by politicians than technocrats. We are fed information that the reason this project is so important is to reduce road carnage and encourage increase in flow of traffic for trade. Really? I thought the primary reason for dualisation was because traffic was already almost at full capacity on an existing road, not to reduce crashes nor to attract future traffic. Seasoned technocrats should confirm to you that dualisation is a function of capacity first, other things secondary.
Obvious examples exist. On Harare– Chitungwiza road link, if you imagine that road being one lane per direction, there would be a massive queue of vehicles in the morning rush along the length of road, with impatience forcing even the normally careful driver to try to overtake. It’s not the road crash which is the primary problem. That is a result of the road operating at full capacity causing delays, frustrations and undesirable behavioural influence. The minute you provide additional lanes, flow immediately increases since at a certain point, instead of one vehicle passing there can be now up to four in one direction.
Harare-Norton road link is another example. The same is pretty obvious for urban major roads linking some residential areas to workplaces or town centres.
When you talk of dualising Beitbridge-Harare, Harare-Chirundu, Harare-Mutare, Harare-Bulawayo, you drop the ball. Traffic volumes drastically drop once you leave the urban radii of 10km outside towns in most cases.
Most traffic is local. The inter-city roads then no longer operate at anywhere close to full capacity. Depending on terrain, different dynamics start to play. Unfortunately, where a road crash occurs, instead of addressing root causes politicians at times prescribe a solution approaching it with a bias without necessary calling for investigations nor consulting with technocrats.
And it becomes difficult once a public announcement has been made for technocrats to be seen disagreeing with the declared policy, for that is what it becomes once a public announcement like that is further endorsed by those in authority who become emotionally attached to the case.
It is made that much worse where a person has travelled on typically dual lane N1 North highway in Republic of South Africa or elsewhere and comes back thinking that it’s the way engineering should be done locally. Yet SA is doing it for its own community, industries and trade benefit.
Talk of Road Carnage
Here is the deal. A number of road crashes can be attributed to dangerous overtaking due to poor judgment by drivers at high speeds. The issue is then not to dualise the whole road but rather to introduce strategic overtaking lanes only at specific road rises, because the climbing gradients slow down heavy traffic, which should then yield to the slow lane to allow impatient drivers to pass without killing anyone. The downward lane remains as is. And we employ these overtaking lanes at all identified spots. Technocrats can identify them from the design coupled with traffic crash data.
Every time there is a bad road crash an announcement is made that the roads are too narrow and dualisation is the solution. And this is where I silently scream, IT’S NOT DUALISATION. Try just shoulder widening if that’s the cause! I travel a number of times from Beitbridge to either Bulawayo or Harare. I am able to travel freely at the maximum allowable speed until I catch up with a slower vehicle after a long travel.
At such point, where visibility allows, I safely overtake. And where the road is in a rising winding area, I get to feel where the overtaking lanes could be effectively placed. What I can say is that even on straight stretches, animals, donkeys on the loose pose the greatest danger on some sections of the roads. We “widened” the portion of Beitbridge-Bulawayo road adding the shoulders, but at certain times and locations, there is always some animal-vehicle crashes, especially at night.
On a number of cases also the state of the vehicles along these corridors has been the cause of road crashes. Burst tyres, failed breaks, high speeds in low-performance vehicles have caused some horrendous crashes on these roads. One must understand that dualisation will not suddenly sanitise a foolish driver. One doesn’t suddenly behave well because the road has dualised. In fact, only the nature of road crash will change. It is proven that psychologically when drivers see a wider road passage, their speeds tend to increase and drivers push their vehicles to the limit unless there is very effective policing. In some major developed nations there is deliberate narrowing of passages to passively reduce speeds.
Is it priority for now?
Why should I seem to be against wholesome dualisation? Because engineers don’t work “outside the box”. They do not prescribe solutions blind to prevailing economic and social environment. Road designs must take into account sustainability, affordability of client and the public benefit.
Remembering too that the highways are not always benefiting the communities through which they pass. A village along a dualised highway is not going to benefit from fast moving traffic past its village. And if we are building these roads for benefit of some travelling cross-border truck passing through to Zambia or Malawi then our priorities need revisiting.