In Belarus lynxes quite often visit road pipes. In the warm season, they mainly use road pipes without running water. In winter, when water is covered with ice, almost all pipes that are large enough are in lynx usage.
We tried to investigate this phenomenon and found four different purposes of lynxes to come to a road pipe. First, a road pipe is something visually outstanding in the habitat structure at forest road. Such remarkable spots are marked by carnivores, including lynxes. Snowtracking data suggest that about 90% of visits of road pipes by lynxes (more than two hundreds cases were registered) was, at least, partly for territorial marking. Also, we noticed that approximately in 60% of the registered cases lynxes were walking at the road-forest ecotone, then they entered the road pipes and suddenly (i.e. suddenly for the possible prey) appeared on the opposite side of the road. Once, a lynx killed a roe deer at the opposite side of the road close to the pipe entrance. Another time a raccoon dog was killed by a lynx with such a manner. So, passing road pipe by lynx has also a hunting sense. During rainy weather or wet snow cover a lynx, while entering a road pipe, shake up and sometimes roll to dry the wet fur (17 registrations), and sometimes they rest inside (5 registrations, at least). Two of the five resting (maybe hunt-watching at the same time) continued quite long, for approximately 7 and 11 hours. Being inside road pipe, lynxes couched on some substratum inside (sand, dry remains of vegetation).
Zoology by Vadim Sidorovich 
That’s interesting. Maybe the road pipe is like a temporary lair for the lynx.!
It seems the Lynx is using these manmade road pipes as part of its hunting strategy , a big surprise to me which shows great intelligence on the part of the Lynx , thanks for posting
Maybe it’s for safety or protection from its enemies. Any animal attacking it has only one way to do so. When your back-up onto a wall you can fight better, and your enemy can’t get you from behind especially if there is more than one attacking you. Plus, it probably stays cooler in hot weather, holds the nighttime coolness. Also, a great hideout for getting closer and catching its prey.
Why not, maybe these needs are also essential for lynxes to visit road pipes.