Sign within signs

Today I was thinking about signs and what they mean to us and how we know what they mean or what we make them to be. I looked up street signs on google images and found a sign that had the meaning of unusual ice conditions. However, within this sign are many others. There was a picture of a car swerving which to me at least means be careful there could be ice or that there is a sharp turn ahead usually so I should watch out. There is also a picture of a temperature gauge that is like half red. This usually means to me that it is not freezing but still not really hot outside. However, beside the temperature gauge is words that say <-0 Celsius. So when you add this into the mix there is a whole different meaning. It is not just a sign that has two really random pictures on it but it tells us that we need to watch out for those conditions when it is below 0 degrees. We can also pick up the fact that it is a warning because of the color of the sign. We usually put the color red with stop or the color green with go or a street sign but this sign was yellow and to us that means it is warning of us something not what the weather is like outside. It is not a matter of what the sign says in parts but as a whole that makes it have some type of meaning to us and makes us pay closer attention. Although without the words below that say unusual ice conditions someone who is usually from Florida or a warmer climate might be confused and make it mean something else because they are not use to those weather patterns. So even though someone like me who is from Pennsylvania may understand it or get the warning behind it someone from a warmer place would be confused besides they know that it is a warning because of the yellow color. Signs mean so many different things to different people so sometimes like in this case words are required to get the point across.