Does the moon offer enough light to drive at night? The Argentinians used to think so, often only using the moon to light the road in the southernmost part of the country. That didn’t happen out of economy but had tangible benefits – only in this part of the world though.
Patagonia is a sparsely populated region. From a statistical point of view, only two inhabitants per square kilometer live in this southernmost part of South America, which also includes the Tierra del Fuego archipelago. So virtually no-one outside cities and villages. The largest part of the region belongs to Argentina. And the most important route through Patagonia is National Road 3 which goes from Buenos Aires to the Chilean border at the Strait of Magellan.
In South Argentina it’s currently light until late because it’s summer in the southern hemisphere. In the winter, the region has about the same lighting conditions as Central Europe though, so the duration of the night and moonlight is equally long because of the comparable geographical latitude. But traffic was extremely different a few decades ago.
Let’s take the density of traffic for instance. Although density is the wrong word, really. Even on the national road called the AU03, in the 1970s you’d sometimes only encounter one vehicle per hour or even per night. But lots more animals instead. Llamas, feral horses and cattle, and even up to 1.5 meter tall birds called rheas would jump onto the road. Mostly at night when they were attracted by car headlights. That’s unpleasant not just in Patagonia and may end badly.
To prevent this, someone came up with the idea of driving without lights in moonlight. The Argentinian Government didn’t lose any sleep over it and okayed it. It turned out that not only did the number of dangerous encounters with animals sink dramatically but visibility also increased. At least on clear days and when it wasn’t just a measly crescent in the sky above the Pampas, the moon provided enough light for kilometers of visibility on roads that were generally clear of oncoming traffic.
Today, Argentinians drive with their lights on at night because even in Patagonia and the part of Tierra del Fuego that belongs to Argentina there’s more traffic on the roads. And this takes us to the reasons why the South American experiment is not recommended in other regions.
The AU03 and many other roads of Patagonia often go on dead straight for hundreds of kilometers and the terrain is flat. Well, Pampas, what can I say. So the route is easy to identify. To the left and right were rarely human settlements and hence no light. As little as a meager light in a building or car headlights make the eyes less sensitive for quite a few minutes. They then take up to a quarter of an hour to go back to full sensitivity. And then even the light of the stars would be enough for walking.
Today, there are virtually no corners of the world with such lighting conditions. And then there’s the moon which won’t always provide ideal lighting for driving at night after all. By the way, it’s not known whether truckers used to schedule their tours of Patagonia following the moon calendar. Quite possibly.