Highways 101

Origins

The origins of traffic management reveal a fascinating evolution of the stop sign. Kurt Kohlstedt explains that early attempts at traffic control were ad hoc, with people standing in streets to manage the chaos as cars became more prevalent 1. Eno, a pivotal figure in traffic safety, laid the groundwork for modern traffic innovations, including stop signs, which varied in design across regions 2. The octagonal shape we recognize today was standardized in 1923 by the Mississippi Valley Association of State Highway Departments, linking geometry with safety 2.

They believed that the shape itself could communicate something like part of what the sign was trying to do could be achieved through the shape of that sign.

--- Kurt Kohlstedt

Roman Mars and Kurt discuss how Eno's contributions extended beyond the stop sign, influencing traffic systems worldwide, including roundabouts in London and Paris 1.

   

Design

The strategic design of traffic signs involves more than meets the eye. Roman Mars notes that the number of sides on a sign correlates with the level of danger it represents, with circles indicating the highest danger for railroad crossings 3. The octagonal stop sign, second in danger level, was initially yellow due to material limitations, but became red in the 1950s as the color became more durable and reflective 4.

The more sides a sign has, the higher the danger level it invokes by the engineers' reckoning.

--- Roman Mars

Kurt Kohlstedt explains that red's association with stopping was reinforced by its use in stoplights, making it a natural choice for stop signs 4. Additionally, blue stop signs in private areas like parking lots are intentionally distinct to avoid confusion with official signage 4.