Wisdom of crowds on the roads?

My daily commute takes me on a route which has a very narrow bridge on a two-way road - just enough room for cars to squeeze through in one direction. This obviously creates a huge requirement for spontaneous co-operation among the drivers since there is usually traffic flowing in both directions. Not an easy thing to do in India where we are notoriously poor when it comes to sharing of scarce resources, esp road space. Obviously the best solution to this would be
an enforcement mechanism like a traffic signal that regulate the flow of traffic in both directions. For some unfathomable reason, the boffins at the traffic department have not yet thought it necessary to provide that. And so that leaves it to the 'Wisdom of Crowds'. If all the drivers were homo economicuses (economicii?) then they would have done the most optimal thing to do - that is to follow an alternating strategy - one car at a time in each direction. This would even out the flow in both directions and most importantly, make it a predictable process where the costs (of waiting) are evenly spread across all the parties. Obviously - this does not happen.

What actually happens is rather intriguing. Let's say that the vehicles are flowing in one direction and there is no backup from the opposite direction. All is well - until the queue starts building up in the opposite direction. At this point, it is completely left to an individual driver's selfless act of
stopping and letting the opposite side start. From that point onwards, it is left to the random occurrences of altruism from drivers in both directions, until there is no backlog in any one direction. Not a very rational process - since there is clearly no incentive for any driver to stop voluntarily because by doing that, she would have selected a high cost option (of waiting) as against the zero cost option (in units of waiting time) of driving through. However, someone or the other ends up doing that each time and what's more, this seems to settle down to a fairly predictable pattern. I have noticed that after 4-5 cars, the opposite side takes over. Which is remarkable since this essentially means that an altruist emerges for every 4-5 drivers. Is it that the drivers, battered by the abysmal infrastructure that passes for our road network, spontaneously arrive at this solution, i.e. is there really a 'wisdom of crowds' phenomenon working here? And then you begin to wonder - why doesn't this happen at all other bottlenecks? For instance, when a traffic signal fails (a not-infrequent occurrence!) then there is almost always a logjam and there is no such self-regulating flow mechanism that emerges.

The only possible explanation is that in case of the bridge, given that it is a predictable situation (the flow problem repeats itself every day), it is in each commuter's 'enlightened' self-interest to contribute to solving the problem. If that be so - why have traffic rules at all? Would a completely self-regulating mechanism appealing to the collective self-interest of the commuters work?? Or is there a tipping point beyond which aggregated individual behavior descends into chaos?