The tunnel honors the French Huguenots who settled in the Western Cape in the late 1600s, fleeing religious persecution in their homeland. Among them was Francois Du Toit, whose name attached itself to the mountain range -- Du Toitskloof, Du Toit's Rift -- and persists in the landscape three centuries later. The connection between the tunnel and the Huguenots runs deeper than nomenclature. These refugees established the farming communities in the valleys on either side of the mountains, communities whose need to move goods and people across the range eventually justified boring through solid rock. The tunnel is, in a sense, the final resolution of a transportation problem the Huguenots created by settling in a valley hemmed in by mountains.

Construction firms Hochtief and Concor attacked the mountain from both sides. Excavation crews drilled and blasted their way through 3,900 meters of rock, working from the Paarl portal on the west and the Worcester portal on the east. The tunnel is the largest curved structure in South Africa, following a gentle arc through the mountain rather than cutting a straight line. It shortens the journey between Paarl and Worcester by 11 kilometers and saves between 15 and 26 minutes compared to the old Du Toitskloof Pass. Currently, the tunnel carries one lane of traffic in each direction, though plans exist to open a second unfinished bore -- the northern tunnel -- for eastbound traffic, which would double capacity and separate directional flow.

On an average day, 12,000 vehicles thread through the tunnel's single bore. During holiday peaks, that number can nearly double -- 22,500 vehicles squeezed through on busy days, with a record 18,200 on a single April day in 2002. Managing this volume through a two-lane tunnel requires vigilance. Thirteen video cameras feed an automatic incident detection system that monitors for stopped vehicles, wrong-way drivers, speed anomalies, and traffic queues. The system can trigger alarms for any deviation from normal flow. Tolls as of March 2025 range from R53 for light vehicles to R371 for trucks with five or more axles, funding the ongoing maintenance of a structure that never stops working.

When the tunnel opened, it rendered the Du Toitskloof Pass redundant as a national route. The pass was renumbered from N1 to the regional R101, and through-traffic vanished almost overnight. But the mountains themselves remain unchanged. Du Toits Peak still rises to 1,995 meters above the tunnel, its slopes still catching snow in winter and cloaking themselves in fynbos in spring. The tunnel has altered human geography -- making Worcester a reasonable commute from Paarl, integrating the Breede River valley more tightly with the Cape Town metropolitan area -- without touching the landscape above it. Travelers who take the old pass can see the tunnel's portal from the heights, a concrete mouth swallowing vehicles that would otherwise spend an hour navigating switchbacks. Below ground, drivers see nothing of the mountains they are passing through. The convenience is total, and the loss is invisible.