A history of traffic sign boards

WEB DESK: Curious about the origins of traffic signs? If so, join us on a fascinating journey through the history of traffic signs, dating back almost a century, as we explore the insights provided by the YouTube channel ‘Drive Partner.

In the early 1900s, the United States was witnessing the emergence of the automobile era. As citizens took to the roads in their newfound automobiles, a need arose to ensure safe and efficient travel. It was during this period that automobile clubs began to form, comprised of passionate individuals who saw a need to mark their local highways with signs to warn and guide drivers.

However, this grassroots effort resulted in a patchwork of sign designs and messages scattered across different sections of highways. This lack of uniformity in road signage soon led to confusion among motorists, highlighting the necessity for standardized traffic signs.

In the year 1924, a significant step toward achieving national uniformity in road signs was taken by the Bureau of Public Roads. Designers faced a unique challenge: they needed to create signs that would effectively guide a largely illiterate population of motorists. Consequently, the early traffic signs placed great importance on color and shape, two components that have remained fundamental to road signs ever since.

In this era, the signs lacked the reflective technology we commonly see today. It was in 1924 that bright yellow became the designated background color for all warning signs, while white became the background color for all other signs. These lighter hues provided optimal contrast with black lettering, particularly when viewed by headlights during nighttime travel.

Later on, signs incorporated glass beads to produce a reflective effect, enhancing visibility for nighttime drivers. These beads, about 0.75 inches (20 mm) in diameter, were strategically affixed to the signs, forming numbers and symbols to inform and warn those navigating the roads after dark.

A groundbreaking development in the world of traffic signs occurred in the 1940s when the 3M company introduced retroreflective sheeting. This material, featuring reflective elements such as glass beads embedded in or under a transparent plastic film, revolutionized the visibility of signs, particularly during nighttime hours.

Unlike diffuse reflection and mirror reflection, retroreflection involves light beams bending and returning toward their original source. This unique property greatly improved the effectiveness of road signs.

The very first traffic sign employing this reflective sheeting was installed on the outskirts of Minneapolis in 1939. The surface of the sheeting was covered in tiny glass beads that facilitated the desired retroreflectivity. However, early versions of this technology had their challenges, such as accumulating dirt on the grainy surface and reduced reflectivity in wet weather conditions.

Innovation and problem-solving prevailed within a few years. An enclosed lens system was devised, essentially shielding the beaded sheeting with a transparent film that preserved its retroreflective qualities. This type of sheeting, known as “flat-top sheeting” at the time, is now recognized as engineering grade sheeting and is cost-effective for use on signs in areas with light traffic and slow speeds.

A significant leap forward occurred in the late 1960s with the invention of encapsulated lens sheeting, which involved adding a resin base and an additional reflector coat behind the glass beads. This high-intensity material proved to be three to four times brighter than engineering grade sheeting, and it maintained its reflectivity over a longer period. Consequently, it became the most commonly used type of reflective sheeting.

The next major innovation came in 1989 when microscopic prismatic reflectors replaced traditional glass beads in sheeting design. With approximately 7,000 microprisms per square inch (about 10 per square mm), this sheeting type boasted three times the brightness of its encapsulated lens predecessor. Moreover, it proved to be the most durable and, understandably, the costliest type of high-performance sheeting available in the market.

Over time, there have been enhancements in standardization, accompanied by the introduction of additional signs and symbols to align with new traffic laws and regulations. As traffic patterns, road layouts, and vehicle technologies evolve, traffic signs will remain adaptable to these changes, as we see today.

The journey of traffic sign evolution, from the scattered efforts of automobile clubs to the development of advanced retroreflective sheeting, has undoubtedly contributed to safer and more efficient travel on our roadways. It serves as a testament to human ingenuity and the continuous pursuit of enhancing road safety for all.