Warning Sign - History

History

Some of the first roadside signs —ancient milestones— merely gave distance measures. Hazard warnings were rare though occasional specimens appeared, such as the specific warning about horse-drawn vehicles backing up which was carved in stone in Lisbon's Alfama neighborhood in 1686. The early signs did not have high-contrast lettering and their messages might have been easily overlooked. Signs were written in the local language (example); symbolic signs, though long used on certain tradesmen's signs (like the pawnbrokers' tri-ball symbol) were to be used for traffic only much later in history.

Complex signage systems emerged with the appearance of motorcars. In 1908 the automobile association in West London erected some warning signs. In 1909, nine European governments agreed on the use of four pictorial symbols, indicating bump, curve, intersection, and railroad crossing. The intensive work on international road signs that took place between 1926 and 1949 eventually led to the development of the European road sign system.

As the 20th century progressed and also as traffic volume and vehicle speeds increased, sign-visibility and nighttime use capability gained significance. Earlier flat painted signs gave way to signs with embossed letters. Circa 1940-50 in countries with many vehicles, wording might be spelled out with so-called "button copy" —letters dotted with reflective glass spheres for night visibility. Button copy signs with plastic pips rather than glass appeared in the 1970s. Flat metal signs reappeared in the 1980s with the widespread use of surfaces covered with retroflective sheeting materials like Scotchlite.

In Eurpoe, the 1968 Vienna Convention on Road Signs and Signals (which became effective in 1978) tried, among other things, to standardize important signs. After the fall of the Iron Curtain and greater ease of country-to-country driving in the Eurozone, European countries moved toward lessening the regional differences in warning signs.

In modern regulations, U.S. warning signs are classified as Series W signs, such as: W1 Series (curves and turns), W2 Series (intersections), W22 Series (blasting), et cetera, ending with the W25 Series (concerning extended green traffic lights). For no readily apparent reason, there is no W21 Series. Some U.S. warning signs are without category while others like the warning stripes at tunnel portals or plain red End of Roadway signs are classified as Object Markers (OM Series). In the U.S., Stop and speed limit signs fall under the R Series (Regulatory). Modern U.S. signs are widely standardized; unless they are antique holdovers from an earlier era, oddities like a yellow Stop sign or a red Slippery When Wet sign would typically appear only on private property —perhaps at a hospital campus or in a shopping mall parking lot.

Street sign theft by pranksters, souvenir hunters, and scrappers has become problematic: removal of warning signs can contribute to traffic collisions and also costs municipalities money to replace lost signs. Some authorities affix theft-deterrence stickers to the back sides of their signs. Some jurisdictions have criminalized unauthorized possession of road signs or have outlawed their resale to scrap metal dealers. In come cases, thieves whose sign-removal lead to road fatalities have been charged with manslaughter. Artistically-inclined vandals sometimes paint additional details onto warning signs: a beer bottle, a handgun, or a boom box added to the outstretched hand of the Pedestrian Crossing person, for example.