The pass was constructed between 1984 and 1988 at the then staggering cost of R125 000 000. Leading up to the Huguenot Tunnel from its south side, is an awe-inspiringly beautiful, high-altitude viaduct bridge (the first of its kind to be built in South Africa) The bridge is simultaneously curved and cambered --constructed by the incremental method.  It soars high above the farm-patchworked Miaspoort Valley. The 4km-long tunnel drastically reduced the distance of the old pass by 11km. (Please note that the Google Earth satellite imaging cannot 'read' a tunnel; it instead follows the track of the road, so ignore the steep spike in the middle of the vertical profile.
The Huguenot-Tunnel is a two-lane carriageway of 3913 metres. There is two way, left side driving traffic. The main control centre is 6 km from the nearest end of the tunnel. 
It extends the N1 through the Du Toitskloof mountains that separate Paarl from Worcester, providing a route that is safer, faster (between 15 and 26 minutes) and shorter (by 11 km) than the old Du Toitskloof Pass travelling over the Mountain.
Geological surveys and design started in 1973, and excavation followed in 1984, tunneling from both ends using drilling and blasting. The two drilling heads met with an error of only 3 mm over its entire 3.9 km length. The tunnel was finally opened on 18 March 1988.
The construction of the older, Du Toit's Kloof Pass, has a long and interesting History that dates back to long before the Italian Prisoners of War, during World War11, built wonderfully constructed road, with its beautiful scenic route, travelled these days by many motorists. The pass is named after Francois Du Toit, a French Waldesian, who with the Huguenots arrived as refugees in the Western Cape, fleeing religious persecution in their own country. On his arrival he acquired a piece of land for farming by the Dutch Authorities, which he called: 'Kleine Bosch', just below the Hawequa Mountains. He was the first to cross the "Neck" above his Farm, and look down into the Valley beyond, that bears his name. There was a gradual expansion of farming activity in this region, and by 1738, Jacobus van der Berg was grazing his cattle in Du Toit's Kloof , beyond the top of the Pass. Gradually the cattle track called the "Hawequa", by the Bushmen Community of the Cape Wineland Drakenstein. (It was a steep and tricky a route, that only cattle could really make use of it.)
In 1778 Governor, Van Plettenberg made mention of a wagon road that was being constructed, but of that plan, nothing really of note came from it. The Hawequa cattle path started not very far from the old farm of 'Kleine-Bosch'. Blouvlei Valley falls between Wellington and the Hawequa neck, taking a zigzag course up the slope, then turning north-east crossing the buttresses, before straightening into the Kloof beyond the neck. Forty years past, when then a enterprising German farmer called Detlef Siegfried Schonfeldt, a former lieutenant in the 45th Württemberg Hussars, who had purchased a Farm in the Du Toit’s Kloof, approached the farming community areas of Worcester, Paarl, Stellenbosch and Franschhoek, suggesting that they should contribute to the building of a road through the Du Toits Kloof , which would benefit them all. After much debate the farming community agreed, and the money for the construction of the road was raised. Funds were even received from far away towns such as Beaufort West and Cape Town itself. Soon the government of the day though, became involved in the project and supplied the necessary explosives for the task, as well as the necessary tools. Soon Schonfeldt went to work, concentrating on the 'Kleingat'- small hole. This was the  most difficult section of the Pass. Within two years, he managed to build a wagon road over it. This depleted the funds that were made available to him by the farming community, so he approached the Government, offering to donate the Kloof to them on completion, should they supply the necessary amount of money required to complete the project. In his opinion 60 laborers would be enough manpower required for this task within 4 months. Lieutenant Charles Alexander of the Royal Engineers was assigned to investigate the matter. He cast doubt on the project, and to his mind the old path was more than sufficient for the purpose intended. Taking in his advice, the authorities turned down Schonfeldt’s offer, as a result he was financially ruined. The matter was again raised in 1858, this time by George Pilkington, a civil engineer, who surveyed a proposed route through the Mountains. Again due to the lack of funds brought this project to its end!
In the 1890’s, a manganese mine was opened in the Mountain above Du Toits Kloof, situated between Miaspoort and the old Kleigat. Transporting the ore was the mine’s main problem. An attempt to overcome this was to use an aerial cableway. The cableway was to carry the ore from the the mine to the top of the neck, then down towards Wellington. The problem was never solved, and the mine eventually closed down!
The next road builder of Du Toit’s Kloof was Jannie le Roux of the farm called 'Verdun'. He started farming in the Area at the end of World War I, and built himself a private road in order to have easier access to his various camps. He used a special little donkey-cart only 3 feet wide, and was able to reach his lands. Now the road was only 4 feet wide! Fortunately for his own personal safety he decided to build a second road higher up the slope, which was better constructed, running about 600 feet below the present pass of today. The le Roux's road could not be used as a public road and in 1935 a National Road Board meeting was held. Interest in building a Pass was revived. In 1940 the Government Engineer Mr. P.A. de Villiers conducted yet another survey and finally it was decided to go ahead with his plan to build a road through Du Toits Kloof. Not long afterwards South Africa with the outbreak of World War II, was to host a large amount of Italian Prisoners of War, with some 10,000 detained at Worcester.
The Government had knowledge of the Italians, whom they considered amongst the best Road and Pass builders in the World at the time, which would just cost them for their labor- their food. The Italians agreed, and those specializing in civil life back in Italy in this type of work were chosen, and rail coached down to the nearest stopping post to the construction area, from where the necessary machinery and tools were provided.
World War II came to an end, and the Italians had to be repatriated, leaving the work left to be completed by local labor. In 1949 the Pass was completed. At a cost of 750,000 English Pounds. A well worthwhile project despite the cost involved. As this would benefit future generations tremendously.
Article of the History of the Du Toits Kloof Pass courtesy of Cav. Andre E. Martinaglia
This Pass has been undergoing tremendous improvements, in the 2020's and now has a few double-lanes for passing and new circles as it passes through Ashton.
-33° 43' 57.3849", 19° 8' 47.3723"