How a city painter curbed bad driving by inventing rubber safety cones
10 March 2023
The modern PVC safety cone evolved out of very humble beginnings. Getty Images
Safety cones are abused in so many odd ways. Everyone at all ages has run them over, kicked them a country mile, or bellowed animal noises out of them into the void. But as fun and silly as these antics are, what makes the safety cone such an ingenious invention is simply this: It’s a nearly indestructible item with a commonly understood message. How often do those come around?
For Charles D. Scanlon, managing the chaos of vehicle traffic was an everyday reality. You see, Scanlon worked as a city painter for Los Angeles in the Street Painting Department in the late 1930s. He was no stranger to the hell that would break loose when the stroke of a brush altered the status quo of traffic. Drivers’ unpredictable responses to the interruptions made the road repairs more dangerous than they ever should’ve been. The safety barriers, which were often made of wood, were common casualties on the job sites.
Wood barriers wall off a viaduct project at the intersection of Huntington and Soto in Los Angeles, California, 1937. Los Angeles Examiner/USC Libraries/Getty Images
Whether lugged out to protect wet paint or city workers, wooden barrier designs were primitive and bulky. They were also easy for drivers to clip, and not very forgiving to vehicles that might impact them. (Heavy iron pedestals were also used to deviate traffic back then. Yikes.) As noted in Scanlon’s first patent application for the “Safety Marker,” filed February 17, 1941, he lays out the arguments—obvious, in hindsight—against using wood construction:
At present, it is customary to use small wooden tripods or larger wooden barriers to indicate the presence of dangerous spots in the highway such as those caused by repairs, etc. but the smaller tripods are not easily seen and are readily broken, while the larger barriers present a real hazard to an automobile which may accidentally strike them. Furthermore, the tripods must usually be made up for each job, while the barriers present considerable of a storage and transportation problem.
Scanlon’s reasoning worked from several angles. Firstly, it’s easy to agree that no driver needs a 2×6 penetrating their windshield, and that no pedestrian wants an impromptu projectile. The old markers raised durability concerns, as well. Unless you’re a craftsman working in fine furniture, wood is a bend-it-and-it-breaks material. Constant repairs—or, even worse, filling up landfills with splintered remains—aren’t practical for money-conscious city officials.
To top it all off, the larger, sawhorse-styled barriers were inefficient to set up, store, and haul around. While safety concerns may attract bureaucratic interest, improving the budget’s bottom line always grabs serious attention. Scanlon’s design wisely addressed both.
USTPO
Scanlon focused on using rubber and fabric from old tires. Since the early 20th century, rubber had taken the automotive world by storm. Tires, seals, valves, wiring, and all sorts of components utilized the material. By the 1940s, rubber was an understood medium, and the perfect realization of Scanlon’s concept: a tough-as-nails, cone-shaped marker that was lightweight, stackable, and difficult to topple. Even better, Scanlon knew a local tire-shop operator—Rodney B. Taylor, who would eventually become his business partner—who could help make prototypes.
Scanlon initially thought that, for the cones’ bodies, layering lightly rubbered fabric (like papier-mâché) was the way to go. The cones’ bases were to be heavier, to ensure a low center of gravity, and could be built from more rigid layers of fabric. The cone could then be vulcanized together—one solid form of reused scrap. However, Scanlon kept an open mind to the possibility of new materials and from-scratch manufacturing methods.
While I prefer, for reasons of economy and convenience, to form both the body and the base in the manner just described, it will be apparent that new materials instead of reclaimed materials may be used throughout if that is desired. In either event, however, I prefer to employ a relatively large amount of fabric in the base, both to decrease the expense and also to prevent the base from being too “live.”
Scanlon went so far as to make considerations for his fellow painters, the guys toiling over crisp roadway lines.
On the underside of the base, I provide a plurality of pads or feet which hold the base above the surface of the highway and permit the marker to be placed on freshly painted surfaces without danger of smearing.
The hole in the top of the cone had another important function. As Scanlon explains, it prevented suction and allowed air to escape more easily when cones were stacked or separated quickly. He also suggested that it could provide an opening for a flag, with the cone serving as a holder of sorts.
Early models are considered antiques today and are periodically listed with online auctions. For this 28-inch model, the seller asks $180. eBay
In 1951, California Interstate Rubber Corp. began producing square bases on Scanlon’s design. eBay
Scanlon’s first patent was finally approved on November 2, 1943, during the throes of the Second World War, which caused material shortages and stunted his progress.
Four years later, the California-based Interstate Rubber Products Corporation, led by Charles Terry, teamed up with Scanlon to finally begin manufacturing his design professionally in 1947. Leaving behind Scanlon’s original recipe of tire scraps, Interstate Rubber used heat-pressed rubber sheets to make cones in abundance, and the City of Los Angeles soon became Scanlon’s inaugural big-fish client.
The cones were an irrefutable hit.
From California to Michigan: The Michigan State Highway Department (now known as MDOT) placed an order for Interstate Rubber cones in 1962. eBay
But what’s a great success story without an adversary?
One day, a fellow by the name of Isador D. Blumenthal, president of the Radiator Specialty Company, Inc. in North Carolina, took a shine to the traffic cone after seeing it during his travels out West. He wanted in. Repeatedly, he tried to court Scanlon and Interstate Rubber into a transcontinental partnership by securing a license to the patent. Again and again, Blumenthal was rebuffed.
He couldn’t let go of the cone. Blumenthal eventually realized that because Scanlon’s safety marker was a cone-shaped derivative of other historical objects, he could legally argue that the cone wasn’t a novel invention but merely a replication, and thus under less-ironclad copyright protections.
What did Blumenthal do? He began making strikingly similar traffic cones en masse, tweaking the shape of the base (a square vs. Scanlon’s circle) in a transparent attempt to skirt infringement claims.
Safety Cone Traffic Corporation, an offshoot of Interstate Rubber, had already begun to try square-based designs in tandem with the round-footed originals. Blumenthal’s square “Safe-T-Cone” began sprouting up in 1951 anyway. Mr. Sour Grapes even went so far as to pursue his own patents in Canada and the United States.
And so began: The Cone Wars.
Not really. But a legal battle did ensue. Interstate Rubber and Scanlon couldn’t keep control of their intellectual property. Rival cones soon flowed from both American coasts, and in 1958, rubber and plastic safety cones started gaining international appeal, spreading to the United Kingdom.
General Curtis LeMay, Air Force Vice Chief of Staff, pilots a go-kart around Andrews Air Force Base runways in 1959. This moment of hoonery made possible by Scanlon’s safety cones. Bettmann Archive/Getty Images
Scanlon never rested on his laurels. Preferring his inventor’s cap on, he constantly looked to improve his original safety marker, amongst a handful of other traffic safety innovations.
On February 14, 1955, he applied for yet another patent that advanced his life-changing cone design: little kickstands for the bottom of the cones. When crews hucked cones into place, perhaps tossing them from the bed of a moving truck, the rubber additions meant the cones were more likely to stay upright, thus saving the crew time. The nubs also prevented the round-based cones from rolling when tipped over—crucially, without impeding their stackability.
These nuances were a sort of cherry on top of an amazing contribution, even if circular bases were ultimately inferior to square ones. Scanlon’s unrelenting attention to detail, and his consideration for the worker’s experience, show that he never forgot himself, where he came from, or the problems he sought to resolve.
USTPO
Today, hundreds of safety cone designs (comprised of PVC polymer, mainly) have taken over the traffic landscape all over the world, speaking with an unanimous voice in a language everyone can understand: go this way, not that way. Do they keep every conehead driver in line? Of course not. But they do a darn good job, and in a much more forgiving manner than what preceded them. We can all thank Scanlon for that.
Now, if only autonomous vehicles could understand their brilliance the way that we humans do …
Bear tested. Bear approved. Wolfgang Kaehler/LightRocket/Getty Images
Article courtesy of Hagerty