Oct 312011

Traffic signs are a part of every day life. The symbols, shapes, colors and pictorials are etched in our minds and help facilitate a safe journey along our roadways. But where did all of this start?

Milestone to Traffic Sign

Today’s road signs evolved from Roman milestones. The early milestones wereTraffic_sign Roman Milestone reference points that provided numbered markers typically seen along the road or at intervals of one mile.  For example, the Romans used large stone columns to convey directions and the remaining distance to Rome. Indeed, all ‘road signs’ point to Rome.

During the Middle Ages (5th -15th century) road signs had marginally evolved. It was common to see many multidirectional signs at intersections pointing the way to distant villages and towns. In some cases, there were also mile markers that showed the distance to cities.

Traffic Signs For High Bicyclists

Ordinary_Bike_TrafficSignsAs more and more travelers became riders of the high or ‘ordinary’ bicycles in the late 1870s and early 1880s, the cycling organizations began to erect signage that warned of potential hazardous conditions along the thoroughfares. These eager road pioneers navigated unfamiliar roads and called out the need for signage that warned of slippery or steep slopes rather than giving distance or directions.

It wasn’t until the invention of the automobile that traffic signs became more important. In 1895 the Italian Touring Club designed one of the first modern-day road sign systems. By 1900, a Congress of the International League of Touring Organizations in Paris reviewed proposals for standardization of road signage.

In 1908 the International Road Congress in Rome set the basic patterns for most traffic signs. Shortly afterward, in 1909, nine European governments agreed on the use of four pictorial symbols, indicating “bump”, “curve”, “intersection”, and “grade-level railroad crossing”. Between 1926 and 1949 governments worked on adopting international road signs that evolved into the European road system of today.

The U.S. Traffic Sign

The invention of the automobile was the real ‘driver’ behind the adoption of signal devices and improved signage along roadways.  Even though the European sign system was the basis for the American sigh system, the United States, in keeping with their pioneer spirit, decided to develop their own signage systems.

Traffic signs_MunicipalSign

Beginning in the 1960s America gradually acquiesced, using the international symbols to depict road conditions, speed limits, and other travel information for drivers. Adopting international symbols and pictorials for road conditions and speed limits helped all international travelers, including Americans,  navigate with fewer problems.

Traffic Sign Construction

Pre-industrial signs were made from stone or wood. In the late eighteenth and nineteenth century painted cast iron was used in sign construction. By the mid twentieth century, aluminum and other materials gradually replaced cast iron.

In 1924 bright yellow was the background color for warning signs, and white was the background color for all remaining signs. These lighter colors provided the greatest contrast with black lettering, especially at night aided by headlights. Early signs lacked the reflectorized technology prevalent in today’s signs.

Later signs used glass beads to produce a reflectorized effect at night. Beads—approximately 0.75 inch in diameter—were glued on the signs in the shape of numbers (i.e., the speed limit) or symbols to assist nighttime drivers. But these signs did not work well at night. Their porous nature trapped dirt and frozen snow limiting visibility.

The development of retroreflective sheeting by the 3M company in the 1940s 3M retroreflective sheetingchanged the face of traffic signs forever. This material enabled reflective encapsulated lens technology similar to the glass beads but in a transparent plastic film, to increase nighttime visibility.

In 1989 a significant development increased visibility with the substitution of microscopic prismatic reflectors for the traditional glass beads. With approximately 7,000 microprisms per square inch, the improved sheeting produces about three times the brightness of the encapsulated lens. This improved sheeting material is seen in signs today and is is the most durable type of high performance sheeting currently available.

Electronics is the New Generation of Traffic Signs

Today’s new generation of traffic signs feature large electronic displays that change symbols and provide intelligent behavior via sensors or remote controls. These signs can be wheeled along the road to provide electronic messages.

Electronic road sign
Travelers can also see these electronic signs overhead along roadways. These signs can flash pictures or words and can be instantly updated by computer to reflect changing conditions. These electronic signs are even used to alert travelers to potential dangers and give travelers information. Whenever an Amber Alert, an alert for a missing child, is issued these signs flash the information to drivers who may be able to help.

Traffic signs certainly have traveled a long road from the early milestones that were huge stone monuments essentially pointing to Rome.