Road safety a priority on the realignment of N3 Key Ridge

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04-10-2024
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The elimination of the treacherous steep grades and bends between Key Ridge and Hammarsdale on the N3 showcases innovative engineering that is enhancing safety on this R4-billion realignment project by the South African National Roads Agency SOC Limited (SANRAL).

Over the years the stretch has been the scene of major accidents as both heavy duty and light vehicles failed to negotiate the notorious carriageway.

Pedestrians on the highway and hawkers taking advantage of the mandatory truck stop have also contributed to fatalities.

But the realignment currently underway will more than enhance road safety.

Four new major bridges, to accommodate a five-lane divided dual carriageway will also change the rural landscape to boost the country’s economic prospects without degrading the environment.

The N3 is a vital link between KwaZulu-Natal’s ports of Durban and Richards Bay with the economic hub that is Gauteng.

As a gateway to the rest of the continent, it is one of the country’s Strategic Integrated Projects.

Major accidents on this national route often cause costly delays to cargo deliveries and impact on commodity chain supplies.

The four-year project was designed by BVi Consulting Engineers Western Cape and is currently being constructed by WBHO Construction and targets completion in 2027.

Project structures resident engineer Kevin Volmink said two 364 m incrementally launched bridges and two 179 m spine bridges will form part of the construction of new five-lane carriageways and viaducts.

“The incrementally launched bridges are the widest of its kind in South Africa, over 23 m wide incorporating steel struts,” he said.

“This section of the N3 has several road safety challenges, particularly to what we refer to as the geometric alignment. Heading from Durban towards Pietermaritzburg there is a continuous steep downhill and, in combination with tight bends this poses a challenge for heavy vehicles.

“When they are loaded, they need to resist the load they are carrying from accelerating uncontrollably downhill. To mitigate this risk there is a mandatory truck stop before the descent. This allows them to stop and engage a low gear before descending down the steep grade towards the Peacevale off-ramp. Compliance with the mandatory truck stop is however, poor leading to runaway trucks.”

“As they descend, they meet a horizontal left curve. Some manage it, but with a heavy load and moving too fast, the inertia of that load wants it to continue in the direction of travel.

The truck would be turning left, but the load wants to continue going straight. That is why a lot of them lose their load and overturn in this position.

“A number of drivers manage the left curve, but the challenge is compounded by a right curve in another direction. By the time they get to this point, they cannot manage the change in direction again, and overturn.

“Removing these horizontal curves is one of the most significant improvements to the alignment of the N3 in this area.

“The slow vertical climb for heavy vehicles travelling in the opposite direction is also a challenge because now they stack up behind each other and some breakdown. That presents a difficulty for some of the heavy vehicle drivers who become impatient and try to overtake this train. Now you have two lanes of heavy vehicles, all climbing slowly up the hill and reducing the number of lanes available to other vehicles. Of course, drivers in vehicles able to travel up to 120 km/h become frustrated and, at times overtake in an extremely unsafe manner.

“Both the climbing as well as the descending sections are high accident zones.

“The horizontal and vertical realignment that we are implementing will smoothen and remove the compound curves as well as reduce both the vertical descent and climb, resulting in a straighter and less steep road alignment,” he explained.

“The new improved alignment will make the N3 better, safer, with increased travel time and reduced accidents,” Volmink said.

Local people are benefiting from the project as their roads are being upgraded as alternative routes to accommodate traffic in the event of an accident during the upgrade.

Assistant resident engineer for alternative routes, Mikhail Ramlukan said: “Significant improvements are being undertaken on alternative routes to the N3. These will increase the overall level of service for the wider road network. There are about 50km of alternate routes that we are upgrading, repaving and improving road safety on. This includes upgrading a gravel road to an asphalt road and significant improvement of its drainage.”

Critically, out of the R4-billion budgeted for the whole project, 30% or R1.1 billion is earmarked for enterprises targeted for empowerment as part of SANRAL’s transformation commitment.

They are owned by women, youth, military veterans, those with disabilities and some are enterprises graded 1-4 by the Construction Industry Development Board.

In line with national governments objectives SANRAL has determined that 10% of the workforce should be recruited locally. Although the project has until 2027 to run and only 25% of the work has been done, already at least 450 people have found employment and have been paid R17-million. More than R89-million worth of work has been undertaken by the targeted enterprises.

Just under R10- million has been allocated for training as part of a programme to impart some skills to the community and leave behind a legacy long after the N3 upgrade has been completed.

The mentorship program is for the duration of the project. It helps to breach performance gaps by the subcontractors and addresses any skills gap for the labourers and their supervisors and managers.

The selection of mentees is based on the skills analysis conducted for the Key Ridge-Hammarsdale package, the scope of work that the subcontractor is undertaking and through interactions with the subcontractor during the project life.

Indeed, not only is SANRAL straightening curves on the N3, the lives of local people are also being aligned for the better.