This is definitely a post for cyclists. If you’re in a car, you’ll just turn on your lights for tunnels, and if you’re walking, you’ll probably not be using them. No pictures this time, as the insides of tunnels aren’t that picturesque, even if the geology and engineering are fascinating. I’ll do the major tunnels first, followed by the others. If you know you’ve got tunnels on your route, take lights, but if you get caught out, all is not lost, in many cases. But there are exceptions.
There are tunnels ranging from just a few metres, to over 1km. Each one is a solution to the area’s challenging topography for road builders: the question always being whether to go round or through. But in many cases there was no choice: through was the only way. But, as you enjoy the experience of going through the varied tunnels also try appreciating the ingenuity of solutions.
Anyway, enough preamble. Practicalities and specifics for cyclists…
Col de Rousset. About 880m, straight. Pretty well lit, and though you don’t need a front light to see, one would be wise. A back light is more advisable, though many cyclists go through without one, and drivers are very considerate.
Les Grands Goulets. About 1.2km, curved, medium gradient. Exceedingly well lit. Safe without lights. Its gradient means that it is fast heading towards Pont-en-Royans. (If the old balcony road is ever opened to the public again, go and see it, as it is a wonder of the world. It’s insane, and you’ll appreciate the safety of the tunnel afterwards.)
Boulc. About 800m. Steep (11%), curved, and badly lit, but hardly any traffic ever. Don’t ride without lights, at minimum a back one. I’ve never ridden it descending, as it looks terrifying with that gradient. At least ascending you’re travelling slowly enough to see and for it to be safe.
Col de Menée. About 400m. Unlit, but always lots of light from either end. Lights advisable, but decent-enough sight lines and light.
Gorges d’Écouges. About 500m. Single-track rabbit warren entirely unlit, and limited passing places. Do not attempt to ride without lights under any circumstances. In fairness, road signs warn you well in advance, but you’ll have a long back-track if you miss the signs.
Combe Laval. Short tunnels, the longest one (still short) lit. Lights unnecessary.
Gorges des Gâts. Five very short tunnels. Front light advisable to make sure oncoming is aware of you. Beware of sharpish turn onto bridge, if descending, after longest of short tunnels.
So, in short, if in doubt, take some lights. They might save an extremely long detour.