Crash cushions are a lifesaver

Managing a 385 km toll network, Bakwena is responsible for the N1N4 sections in Gauteng, North West and Limpopo provinces, the N1 from Pretoria to Bela-Bela, and the N4 from Pretoria to the Botswana border. André Wepener, traffic engineering manager, Bakwena, speaks to IMIESA about new safety systems being installed.

Monitoring vehicle patterns and ensuring that optimal crash prevention measures are in place is a top priority for Bakwena. This dovetails with its ongoing asset management, maintenance and new construction programmes to ensure that road users enjoy a world-class experience.

In terms of safety, Bakwena continues to research the best solutions from around the world and recently specified Lindsay Africa’s Tau TubeTM crash cushions at two sections of the N4. The first was installed at the Helen Joseph Interchange to provide impact protection at the approaching ends of new median concrete barriers. The installation of this Tau Tube system was carried out by Basella Maintenance.

“These concrete barriers were installed to prevent illegal U-turns,” explains Wepener. “A key consideration was that the adopted solution to prevent the U-turns would not create an additional hazard to motorists. Investigations showed that concrete barriers were the most effective option. We then added the Tau Tube crash cushions to improve the safety of the installation.”

Designed for 110 km/h impacts

Lindsay Africa fields a wide range of traffic safety systems. The Tau Tube range meets EN1317-3 specifications and caters for impact speeds of 50 km/h, 80 km/h, 100 km/h and 110 km/h. As Ivan van der Westhuizen from Lindsay Africa explains, the specification rating is for light to medium vehicles up to 1 500 kg. The Tau Tube cushion installations for Bakwena are rated for a 110 km/h direct impact. The system also functions as a deflective barrier for side collisions.

Composed of high-strength steel, each crash cushion is a freestanding structure anchored into position on a concrete base. Lindsay Africa supplies them as wide or parallel units. Lengths range from 2.7 m to 6.7 m, with widths from 850 mm to 2 430 mm – and installations can be permanent or temporary.

The temporary installation can be used during road construction. When a head-on impact occurs, parts of the rail-mounted system are designed to slide back or concertina, absorbing and releasing the kinetic energy caused by the crash. Designed to be reusable, the cushion can subsequently be pulled back and restored to its original position by maintenance teams.

Bapong Traffic Control Centre

“Safety and safety compliance are core priorities,” stresses Wepener. “And we took this into account during the construction of the Bapong Traffic Control Centre that operates 24 hours a day.”

All approaching trucks are entering a screening lane and are weighed electronically in motion via pavement-embedded sensors – so called Weigh-in-Motion (WIM). When the WIM indicates that trucks are close to or exceed their legal load limit, they are required to enter the weighbridge to be measured statically, which is significantly more accurate and enforceable. For the approaching west- and east-bound screener lanes, wire rope crash barriers were

installed to provide a barrier between higher-

Lindsay Africa’s new telescopic architecture is designed to absorb energy in a completely new way. The vehicle occupants in this collision survived without injury

A Tau Tube parallel crash cushion installed on one of the approaches to the Bapong Traffic Control Centre

speed light vehicles and the slower travelling trucks in the screener lane. Then, to complete the safety system, Tau Tube cushions were placed at both approaching ends, with this installation carried out by Emeka Civils

“At Bakwena, we combine engineering interventions with strict traffic management control. Safety systems are designed to improve driver behaviour and to preferably prevent or minimise crashes. We’re aiming for zero loss of life and damage to our assets,” Wepener concludes.

www.bakwena.co.za

www.lindsay.com

Bakwena’s new 24-hour Bapong Traffic Control Centre