There are plenty of signs that warn motorists and pedestrians. Road safety signs are a common sight among plenty of highways while other stock safety sign like "Exit" or "Fire Escape" is usually found in buildings.
So, one might wonder where do these come from. History dates it back to the use of Flags. To identify a body of army moving through the battlefield. Some even state that old inns and places of interest used to hang a board with a painted picture by the door. To identify themselves to people who then couldn't read.
Present signs could actually be broken down into four functions:
1. Information: Providing information about functions or services. e.g. Maps, directories
2. Direction: facilities, signs leading to services, e.g. Sign posts, directional arrows
3. Identification: signs indicating service or facility. e.g. Room numbers, floor numbers
4. Safety and Regulatory: Signs giving warning or safety instructions. e.g. warning signs, traffic signs.
These four could then be broken down into two categories. Safety and general. Safety signs are used to warn of possible danger, hazard, or which life or limb could be lost if sign is to be ignored. General signs would point towards directions, and be informative but without any danger to a person.
There are several Internet websites that sell these items. Since safety signs makers in Sydney usually have the World Wide Web as their main outlet for advertisement and customer base. Most that are in use for buildings and others that does not include road safety signs are often made of plastic. With the warning sign printed by a machine. While these were used to be done by hand, in most countries, they have now been replaced by automated printers that are able to make thousands of these signs on a daily basis.
Road safety signs however are made entirely different. They are made from metal, mostly aluminum to keep the costs down, and are painted with a rust proof coating before being painted with their signature reflective paint. Most countries around the world use the color yellow as a basis of warning. Sometimes with either red or black borders.
Though these are more expensive than the plastic signs, they are made to be resistant to rain, wind, dust, and anything short of a tsunami or something that drastic. These signs are made to stand the test of time and be standing for years to come to minimize costs of replacement.