Today’s carport is usually constructed out of steel buildings, which frequently are made with a very high proportional amount of steel that is recycled, including the 95 percent plus of water used to make these products. This idea of recycling steel and the water used to make these metal carports is good because recycling steel helps save the same amount of energy that would power 18 million houses for an entire year. Recycling is an obvious benefit of buying a carport or similar garage buildings, but it by no means is the sole benefit.
Another benefit to adding a carport is the protection that it offers. Boats and recreational vehicles that are stored out in the elements often suffer from damage caused by snow, wind, hail and ultraviolet rays from the sun. But when they are underneath car ports, they are very well protected. The carport is not just used to protect RVs and boats, though. Cars often can be seen underneath these metal garages, as can outdoor power equipment like lawn mowers. And interestingly enough, a car port first was used as educational centers, when Prairie School architects started using them in 1909.
The carport originally was called auto space, but only for a short time. The name was recommended by an architectural firm in Minnesota, but the name never stuck. It could have been because these ports are used to protect much more than autos, or it may just not have had as nice a ring to it.
See this reference for more.