Though tunnel entrances can provide welcome relief from the hot sun or the threat of a lightning strike in an electrical storm, they usually are nasty obstacles for cyclists. The deafening, rumbling echoes of trucks and cars; unreliable lighting; poor ventilation; narrow lanes and the absence of sidewalks can all converge to make a tunnel traverse a nerve wracking experience. We avoid them if we can but sometimes it's just not possible.
The very worst situations are when something changes once inside a tunnel. A couple of times we've confidently ventured into a wide and well lit tunnel only to have it quickly narrow and dim once well inside. Another time we had a dreadful experience when going through a long, steep, curving tunnel a second time and discovering the lighting was out when just a few days prior it was well illuminated.
One long term solution to improving your vision in tunnels is to increase your intake of carrots. Years ago Bill proved it to himself that increasing his Vitamin A intake with carrots really did noticeably improve his night vision, just like the nutrition books said. We make it a habit to eat a carrot a day to support our night vision, even when abroad. It's also available in multi-vitamins, but there are concerns in the medical literature regarding the safety of the vitamin formulation most often used in supplements.
Learning to spot the tunnel symbol on your maps is the first
skill in tunnel management so that if you can't avoid them, you at least know
that one or more is on a day's route. We make sure that our reflective
Illuminite vests and extra lights are handy when packing in the morning if
tunnels are a part of the day's ride.
We've drawn the line on weight and price economy on the side of only having 1 headlight between the 2 of us. Since it is our policy to never ride at night, the headlight is essentially only used in tunnels and is primarily for being seen by motorists. . In addition, the other visibility aids that are always in place are good taillights on each bike and reflective patches on our helmets (that we applied), on the backs of our Shimano sandals and on the ends of our Vaude or Ortlieb panniers. We now have tires with reflective strips on each side and I usually have some type of light on the back of my helmet.
Scouting the Tunnel
Once at a tunnel, we take time to look for a bypass road as sometimes the old road is still passable. We've shuttled our bikes and gear over barricades to get on some old roads and other times have found openings just for bikes. More than once we've gone half the length of the tunnel on the old road only to find it's impassable, usually due to the debris of a rock slide or too much of the road has dropped away. But other times we've delighted in a scenic road without traffic that affords grand ocean or mountain views.
Once we've determined there is no bypass, we size up the
situation at the tunnel entrance. First, we assess the width of the lanes, the
width of any sidewalks, the amount of traffic, the amount of debris or obstacles
on the roadway and sidewalks, the amount of uphill grade and
the lighting to decide whether to walk or ride. Regardless if we walk or ride,
if the tunnel is long or the lighting is poor, we'll don our Illuminite
reflective vests for better visibility. We also have added blinking fob lights
by Cateye to our arsenal, and we'll slip one on each arm for more visibility. I
also have a fabric strip cut from an old Illuminite vest to drape over the back
rack gear on my bike, as I am the caboose in our duo through tunnels.
Bill has the headlight on his bike, so he goes through first. I follow with the better rear view illumination from the helmet lights and reflective fabric strip. We've found that 2 people can get through an unlit tunnel with 1 headlight, but learned the hard way that 3 cannot. Based on that experience, I now carry a Petzl headlamp in with my light fobs to have handy in an unexpectedly dark tunnel. I loop the headlamp's elastic strap around my aero bars, which directs the light at a good angle. It's not bright enough to ride through a completely dark tunnel, but it's sufficient to help me navigate if the lighting in a tunnel disappears.
If it's a bright day and you are traveling through an unlit tunnel, roll into it to the point where it is dark and wait at the curb. Wait a couple of minutes until your eyes adjust to the diminished light. This is especially important on a downhill tunnel as you'll travel much faster than your eyes can adjust. Going uphill it is less important as your pedaling speed is more closely aligned with the speed at which your eyes switch over to night vision.
If you suddenly find yourself blinded by darkness as has happened to us a couple of times, get your feet on the ground, turn your front wheel sharply to the right and very slowly walk with the bike until you hit a curb or a wall. We did this successfully once and another time I dumped over when my front wheel hit a post on the sidewalk's edge. (It was surprisingly frightening to go down in pitch black.) Once at the curb, you can safely shuffle along until your situation improves with a passing car providing some needed light, activating a flashlight, or benefiting from reflected daylight at the exit. We also had trouble in one unlit tunnel with weak batteries in the headlight. We were startled to discover that riding into sudden darkness in a tunnel is extremely disorienting and both times we tended to end up out in the center. An account of our harrowing experiences in unlit tunnels is on the last half of our 2005 journal #6, "The Lake District" under the heading "Tunnel Vision".
Please send us an email if you have any advise for making tunnels safer or more tolerable.