Traffic sign

Traffic signs or road signs are signs erected at the side of or above roads to give instructions or provide information to road users. The earliest signs were simple wooden or stone milestones. Later, signs with directional arms were introduced, for example the fingerposts in the United Kingdom and their wooden counterparts in Saxony. With traffic volumes increasing since the 1930s, many countries have adopted pictorial signs or otherwise simplified and standardized their signs to overcome language barriers, and enhance traffic safety. Such pictorial signs use symbols (often silhouettes) in place of words and are usually based on international protocols. Such signs were first developed in Europe, and have been adopted by most countries to varying degrees. International conventions such as Vienna Convention on Road Signs and Signals have helped to achieve a degree of uniformity in Traffic signing in various countries. Countries have also unilaterally (to some extent) followed other countries in order to avoid confusion. Traffic signs can be grouped into several types. For example, Annexe 1 of the Vienna Convention on Road Signs and Signals (1968), which on 30 June 2004 had 52 signatory countries, defines eight categories of signs: A. Danger warning signs B. Priority signs C. Prohibitory or restrictive signs D. Mandatory signs E. Special regulation signs F. Information, facilities, or service signs G. Direction, position, or indication signs H. Additional panels In the United States, Canada, Ireland, Australia, and New Zealand signs are categorized as follows: Regulatory signs Warning signs Guide signs Street name signs Route marker signs Expressway signs Freeway signs Welcome signs Informational signs Recreation and cultural interest signs Emergency management (civil defense) signs Temporary traffic control (construction or work zone) signs School signs Railroad and light rail signs Bicycle signs In the United States, the categories, placement, and graphic standards for traffic signs and pavement markings are legally defined in the Federal Highway Administration's Manual on Uniform Traffic Control Devices as the standard.