The purpose of a tunnel is to get you from one place to another, preferably alive. The Anzob Tunnel is making no promises in that regard.
5,040 meters of tunneled asphalt make up the connection between north and south Tajikistan, arguably a step up from the former dirt road that was regularly closed due to frequent, almost year-round avalanches. Called "The Tunnel of Fear" by locals, its importance lies in the fact that, unlike the previous route, it avoids cutting through less-than-friendly Uzbekistan. The construction of this route between major cities Dushanbe and Khujand has allowed commerce to flow with far less interruption, and Tajikistan no longer has to be split in two through the entire winter season.
Sounds fantastic, so what's the problem? It can't be that dangerous, at least not as dangerous as an unfriendly territory or a snowed-in dirt road, right?
Let's start with illumination in the tunnel–there isn't any. Aside from the headlights of your vehicle and those of your fellow tunnel dwellers, there is no lighting to speak of. Not completely unheard of, an inconvenience really. Until you realize there are potholes. Not small potholes that give you a little rattle as you truck along, but BIG potholes. Big, axle-snapping potholes that are difficult to see in the dark tunnel, that also happen to be filled with water. Some of them have several feet of water, and are basically small, tunnel ponds.
There is a typical two-lane system, which is obviously completely ignored as vehicles try to survive an obstacle course that includes broken down construction equipment, tunnel ponds, and oncoming traffic attempting to run the same gauntlet from the opposite direction. Things could be worse though, you could always break down. There's a few reasons why breaking down in this tunnel would be less than ideal, especially since the odds are so stacked against getting to the other side unscathed. Besides being trapped in a dark, wet tunnel where other cars are careening around you in chaos, the most terrifying reason to want to keep moving is the lack of ventilation.
With one, pathetic fan attempting to push air around, the tunnel is filled with exhaust so thick that visibility is only a few feet in front of you. While carbon monoxide poisoning is certain, the amount of time you spend trapped would determine whether that exposure becomes fatal or not. There have been many reports of deaths in the tunnel caused by suffocation from the toxic fumes, however, if you can survive all that, then you're home free!
Except for the rocks. There is always the occasional falling rock to keep an eye out for.
That's it though. Other than giant, water-filled potholes, no lights, every-man-for-himself navigation, toxic gasses and the sporadic avalanche, the Anzob Tunnel is totally safe.