Route de l'Hongrin is a spectacular mountain road climbing up to Lac de l'Hongrin with a length of 35.2 km, located in Vaud, Switzerland. The road goes through the «Petit Hongrin», a military zone. Unrestricted access to the area at weekends. Monday to Friday the road is closed for shooting exercises.
The route starts from Aigle, the capital of the district of Aigle in the canton of Vaud at an elevation of 415 m (1,362 ft) above the sea level. After 35km starting in vineyards, then climbing through light woods, the road arrives to Lac de l'Hongrin, at an elevation of 1,255 m above the sea level.
The road crosses the Tunnel de la Sarse (also known as Tunnel de les Agites), a very narrow and rough tunnel built between 1938-1940. This is a single lane tunnel and during weekends and bank holidays users must adhere to a strict timetable for one-way traffic. Cyclists need to be aware that the tunnel, carved out of the rock, has no other illumination other than a few shafts of natural light. The tunnel official opening time is 1 June. Weekends and bank holidays from 7h to 19h : ascent (direction Lécherette) during the first quarter of each hour (00 to 15), descent (direction Corbeyrier) during the third quarter of each hour (30-45).
The road climbs up to Les Agites, a high mountain pass at an elevation of 1,569 m above the sea level. This part of the road is open to private motorized vehicles only in summer. In winter, both the Hongrin road and the Agites tunnel are closed to traffic.
The road includes some steep sections, without market central lines, is very narrow, scarcely wide enough for two cars to pass at the same time. The climb is roughly 13 kms at 9%. In parts, extremely steep even +20% and well above 10% for much of the way.
Pic: Joachim Segui