This article discusses various road infrastructure history and perspectives that could help in improving future infrastructure. The visibility of pavement markings has continued to be problematic, especially where winter and snow are virtually synonymous. The American reinvention of the highway centreline has been described as ‘the most important single traffic safety device in the history of auto transportation.’ The solid white line that marks the right-hand edge is thus considered another significant innovation. The white line delineating the pavement’s right-hand edge was explicitly advocated in the 1961 manual, and the 1978 edition made it required for all multilane rural highways. Such standardization, while it may take time to be codified, certainly does make our highways safer and less stressful to navigate.
Trying to follow barely visible highway lines is a frustration drivers have experienced on many a road, in good weather and bad, in day and nighttime conditions, especially where the lines have become all but totally erased by the rubber tires of traffic relentlessly driving across them.
This is not a new problem, and as long ago as the 1930s the California Department of Transportation—familiarly known as Caltrans—began looking for improved ways to mark highway pavement. However, it was not until the greatly increased traffic and traffic accidents brought about by the postwar boom that serious research began under the direction of the Caltrans engineer Elbert Dysart Botts. The result was slightly raised round pavement markers that came to be known as Botts’ dots. When these white ceramic objects were used in place of or in addition to painted lane markings, they not only projected out of standing water on the road but could also be felt and heard when a driver's tires ran over the line they formed. The problem with Botts’ dots was that they could be used reliably only in regions of temperate climate, for snowplow blades tended to slice the markers right off the pavement. A variety of raised and depressed reflective lane markings has since been developed, but problems with keeping them undamaged, uncovered, and in place remain.
The visibility of pavement markings has thus continued to be problematic, especially where winter and snow are virtually synonymous. Where salt is used to keep roads clear of snow and ice, its whitish residue masks painted lane markings. During the winter of 2014, the Wisconsin Department of Transportation tested an orange-colored reflective epoxy paint at several locations around the Milwaukee Zoo interstate highway interchange to determine if that color was more readily visible than the federally mandated white and yellow pavement markings even under light snow accumulation and in dark and rainy conditions. Drivers did find the bright orange an improvement, but the results of the test remained to be reviewed by the Federal Highway Administration, which as history shows tends to move slowly.
As late as 1917, pavements on rural highways were unadorned with lines or stripes of any kind. It was supposed to be understood that an automobile was to hug the right side of the road when encountering a vehicle coming the other way. However, when approaching a tight curve to the left, some drivers were accustomed to cutting the corner and so driving on the left side as they rounded it. This was of little consequence when traffic was slow and sparse, of course, but if a fast-moving vehicle coming the other way was hugging the inside of the same curve, the vehicles would encounter each other in a sudden game of chicken that would leave little time to react and escape a collision.
Before there were standardized road signs, especially dangerous curves were marked by local residents in an ad hoc way. A “horror sign” might have featured the image of the grim reaper and the words “Just Around Curve” or a skull and crossbones and the warning “Danger—Go Slo.” Such notices were expected to serve as adequate reminders and warnings to the driver to proceed with caution. Marking the road to keep moving vehicles from encroaching upon one another's space is actually an old idea. About five hundred years ago, a road near Mexico City had its centerline defined by stones of a lighter color than the rest of the pavement. This practice persists in some European cities to this day. In the late nineteenth century, bridges on which a collision would likely do damage not only to the vehicles involved but also to the bridge structure itself had lines painted on their road surfaces to lower the risk.
It was also important to control automobiles at crossroads and cross streets and to separate motor vehicles and pedestrians. As early as 1907, stop lines were painted on roads in Portsmouth, Virginia; the first crosswalks are believed to have been painted in 1911 on the streets of New York City. The American reinvention of the highway centerline dates from the early twentieth century and is commonly attributed to Edward N. Hines, a charter member of the Wayne County, Michigan, Road Commission, on which he served from 1906 until his death in 1938. It is Hines's idea that has been described in the trade magazine Michigan Roads & Construction as “the most important single traffic safety device in the history of auto transportation.” Among Hines's other notable achievements was instituting the construction of the first full mile of concrete roadway, which was placed in Detroit in 1909. Two years later, Hines is said to have observed a milk wagon leaking some of its contents and leaving a white stripe behind it as it progressed down the road. This gave Hines the idea for the modern centerline, the first of which was painted on River Road in Trenton, Michigan, just south of Detroit.
The American reinvention of the highway centerline, attributed to Edward N. Hines, has been described as “the most important single traffic safety device in the history of auto transportation.”
The first centerline on a rural highway is believed to have been painted in 1917 in milk white on the portion of the Marquette–Negaunee Road known as Dead Man's Curve, which is located on Michigan's Upper Peninsula. The line was the work of Kenneth Ingalls Sawyer, who was veteran superintendent of the county board of road commissioners and had drafted the state's first gas and weight tax laws, along with a good deal of its other basic highway legislation. As he wrote in the September 1920 issue of Municipal and County Engineering, “the handling of motor traffic upon our main trunk highways through the country is rapidly becoming as serious a problem as traffic control has ever been in our cities.” It was, therefore, necessary to adopt methods of urban traffic control in rural areas. Sawyer related how traffic between the towns of Marquette and Ishpeming, farther down the road past Negaunee, had “become heavy enough to make travel dangerous unless some means of control is adopted.” His means was “white 8 in. center lines upon the black surface of the road upon the more dangerous curves, with an arrow pointing down the right hand side of the road at either end.” He believed that drivers responded to the white line because they had become accustomed to obeying similar devices controlling traffic in cities. The result was an “immediate reduction in the number of accidents.”
Sawyer acknowledged, however, that the centerline was not a panacea; it worked on that road because of its “smooth black surface,” which allowed the white line to “stand out in sharp relief.” To maintain that condition of visibility, the highway patrolman touched up the line every Saturday morning, something not practical on today's interstates.
Clearly the goal of road safety would be better served if the design of road markings and signs did not vary from urban to rural roads, from state highway to state highway. Following studies, conferences, and reports, the American Association of State Highway Officials and the National Conference on Street and Highway Safety issued in the late 1920s manuals for signs and control devices on rural and urban roads and streets. But two separate manuals did not help standardization, and so in 1932 a Joint Committee on Uniform Traffic Control Devices was formed, and in 1935 it published in mimeographed form the first Manual on Uniform Traffic Control Devices, known as MUTCD, which soon became an American standard.
As important as keeping vehicles from crossing over the centerline is, preventing them from veering off the side of the road is equally imperative.
The great demand for the manual caused a printed version to be issued in 1937; the 166-page document covered signs, markings, signals, and islands. (The latest edition, published in 2009, is 864 pages long.) The first manual did not require centerlines everywhere. They needed to be painted only on hill-crest approaches with limited sight lines; tight or restricted-view curves; and pavements wider than forty feet. The acceptable colors for the lines were white, yellow, or black, the choice being dependent on which provided the greatest contrast against the pavement, whose color could vary from coal black for asphalt to almost white for concrete. (Such considerations remain important and dictate that lane markings on concrete-surfaced bridges consist of white lines painted over wider and longer black ones. Concrete taxiways and runways at airports are typically marked with yellow or white lines outlined in black.)
By 1954, forty-seven of the then forty-eight states had adopted white as the standard color for the highway centerline. The holdout was Oregon, whose highway department believed yellow to be the more visible color. Indeed, it is easier to see under a dusting of newly fallen snow, but the State Highway Commission capitulated. In an editorial on the matter, the Oregonian newspaper incidentally noted that the claim that the highway centerline originated in Oregon was unsubstantiated, attributing the concept to “several states” that had “hit on the idea independently at about the same time.” However, in a letter to the editor, Peter V. Rexford, a retired captain of the Multnomah County Sheriff’s Office, claimed that “the first yellow centerline ever painted on pavement” was done under his direction in April 1917. He may have been correct that it was the first yellow centerline.
Oregon citizens were not happy that at midcentury their traditional yellow road markings had been changed, and public pressure caused the highway commission to reverse itself. However, after two years of trying out white, yellow was reinstated. And then just two years later, in 1958, the Bureau of Public Roads decided on white as the standard for lines marking the new interstate highway system. If Oregon did not conform, it stood to lose at least $300 million in federal funds. Citing a series of tests that found yellow to be the safest color deer hunters could wear, the Oregonian editors argued for keeping yellow lines on roads under the sole jurisdiction of the State Highway Department. As for the interstates and U.S. highways, the yellow lines would have to be changed to white.
Soon the federal government reversed itself. The 1971 edition of the MUTCD declared a new standard for marking two-way roads, whether containing a median or not. To emphasize that they separated traffic moving in opposite directions, all centerlines were to be painted yellow. Where there was a median, the line marking the left edge of the leftmost of two or more lanes was to be yellow. White was to be reserved for regulating traffic moving in the same direction. Thus, broken white lines would continue to separate adjacent lanes carrying traffic in the same direction. Oregon had to change its roadway colors again, but this time it did so gladly.
As important as keeping vehicles from crossing over the centerline is, preventing them from veering off the side of the road is equally imperative. The solid white line that marks the right-hand edge is thus considered another significant innovation. Although the idea may have been on the minds of many in the early 1950s, it was the chemist and metallurgist John Van Nostrand Dorr who was prompted by his wife to do more than talk about it. The Dorrs, like a lot of drivers using dark rural roads at night, tended to hug the center line, which aggravated the glare of approaching headlights and caused a driver to veer to the right toward the shoulder and often go off the road. Dorr convinced the Connecti-cut highway department to paint an experimental right-edge line on a four-mile stretch of the Merritt Park-way. When the line proved to help drivers stay centered in their lane, the entire parkway was so painted, along with many additional miles of the state's busiest roads. Other states soon followed.
Whereas wheeled contraptions attributable to numerous Rube Goldbergs were used to paint highway centerlines as early as the 1920s, the invention of an edge-line machine is attributed to one John Edward White, who worked for the Ohio Department of Transportation. One day, while driving down a highway in dense fog, White was having difficulty seeing the road. To drive on, he had to hang his head out the window to keep the median line in view. Apparently independent of Dorr, he conceived of painting a white line on the right side of the road to mark its edge. In dense fog a navigator might have to stick his head out the passenger window, but that would be safer than the driver exposing his head to oncoming traffic. In 1956, to implement his idea more efficiently, White developed a prototype edge-line machine employing a subcompact Crosley automobile chassis. He was encouraged to do this because, whereas the 1948 manual had recommended against the use of edge markings generally, a 1954 revision modified the prohibition. The white line delineating the pavement's right-hand edge was explicitly advocated in the 1961 manual, and the 1978 edition made it required for all multilane rural highways. Such standardization, while it may take time to be codified, certainly does make our highways safer and less stressful to navigate.