A rise in traffic volumes has necessitated the development of a second, northerly bore at the Western Cape’s Huguenot Tunnel to allow for a dual carriageway, South Africa announced during a media briefing at the tunnel on Tuesday.
The 4 km tunnel reduced the road travelling distance between Paarl and Worcester by 11 km and eliminated a climb of some 500 m over the steep Du Toitskloof Pass, providing safe passage for over 75-million vehicles during its 27 years of operation.
While the average traffic volume had increased for all vehicles, heavy vehicle traffic had risen in the order of 5% to 18% a year, which had significantly increased the risks of accidents and was a fire hazard.
South African National Roads Agency Limited (Sanral) Western Cape project manager Tiago Massingue noted that the existing safety equipment in the tunnel had reached the end of its life cycle and its replacement had become urgent.
“The tunnel is one of the Western Cape’s most vital economic assets and it is Sanral’s mandate to maintain the tunnel in such a state that it functions optimally and in the best interest of road users.
“We don't want to sound melodramatic but it is important for the public and the authorities to know the risks we face if works on the tunnel are delayed or do not proceed,” he commented.
Massingue said extensive improvements would have to be made to the current safety and firefighting equipment, including the installation of jet fans to improve airflow; the installation of mechanical controlled dampers in the tunnel ceiling; and the replacement of switchgear and ventilation bypass doors.
A period of six to eight months would be required to carry out the refurbishments and, owing to the nature of the work, no traffic could be allowed in the tunnel during this time.
“To reroute traffic over the Du Toitskloof Pass for such a long period is just not a viable option. Scaffolding will have to be erected to carry out the work and a stop-go control is not recommended, as it would increase the risk of accidents.
“The only viable option is to construct the north bore and once it has been completed, to divert traffic to the new tunnel. The existing south bore systems can then be improved,” he explained.
Sanral Western Cape regional manager Kobus van der Walt added that the socioeconomic benefits of a second tunnel have a major positive knock-on effect for the Western Cape economy.
He said the refurbishments of the existing tunnel and the upgrading of the second bore would be funded as part of the N1-N2 Winelands Toll Highway Project, noting further that a twin-tunnel operation would also make maintenance easier, vastly reduce the impact of an incident or a fire, and allow for better traffic control.