The finances and physics that gave us red barns and firetrucks
Red is for apples. Red is for cherries, red is for stop signs, red is for barns, and red is for firetrucks. We’re taught these associations from a pretty young age, mainly because they’re commonly true, which may in turn bias our future choices about what to paint our barns and trucks when the choice arises. While evolution, genes and cultivation may explain red apples, at a certain point trucks and barns weren’t anything, and someone had to make a choice. So why red?
Price and perception
Starting with firetrucks, the answer isn’t totally clear. We don’t have a written record of the first time someone painted their truck, but there are some stories about the motivation behind picking red. One is that, after an era where volunteer fire-departments sometimes competed with one another, American fire departments wanted to stand out, and painting your truck in expensive red paint was a way to do that. However, this is contradicted by another history which says red was picked because it was the cheapest color for volunteer fire departments to purchase. Finally, a third version points to early automobiles being black to save costs, and that red was picked to stand out from the Model Ts starting to take over the roads in early 1900s.
There are a few problems in these bits of lore, starting with the value of the color red. On a physiological basis, red does stand out to us in daylight, which means that trucks would have stood out from other vehicles on the road. However, that advantage doesn’t hold in dimmer light, and from dusk onward red objects have been found to be harder to see than other colors. To deal with that, more and more fire departments have opted to paint trucks the bright lime-yellow often associated with safety equipment and clothing, as it should stand out in a wider range of light conditions.
Sadly, even that doesn’t guarantee that other drivers will heed firetrucks’ right of way during an emergency. In 2009 it was found that if people are used to red trucks, that’s what they look out for, not noticing the brighter yellow trucks as quickly. This last point might not answer why trucks were first painted red, but it may help explain why they stayed that way so long.
Colors from the cosmos
To figure out the more financially-motivated explanations for red trucks, it may be time to bring up red barns. Barns have historically been painted red because red is often the cheapest pigment to make into paint, which may knock off the “expensive red” theory mentioned above for trucks. It’s cheap because the core ingredient, red ochre, a form of iron oxide (Fe2O3) is quite abundant and therefore cheaper to produce. The reason for that apparently goes well beyond human invention though, extending into deep space.
Stars like our Sun are ‘powered’ by a multitude of fusion reactions, releasing energy, breaking and fusing protons together and triggering more reactions. As the amount of energy in the star decreases, the reactions slow, taking more time to build up enough energy to trigger another round of atomic fusion. At the same time, heavier and heavier elements have a chance to settle in each of these cycles, until at a certain point the energy required can no longer overpower the elemental mass that has built up. The heaviest element that can be produced through this process is iron, and so as stars have cooled and shrank over and over, the universe has had a lot of chances to make a lot of iron. Enough of it has then ended up on Earth, where we can afford to slap it on our signs, trucks and barns.
Source: Why are fire trucks red? by Sarah Calams, Fire Rescue 1