When it opened in 1940, the Arroyo Seco Parkway looked like the future. Its sweeping curves transported motorists between Los Angeles and Pasadena without encountering a single stop sign, traffic light, streetcar, bicycle or pedestrian. It was a roadway designed for the uninterrupted, unimpeded flow of automobiles. It was the work of civil engineers.
If L.A.'s landscape bears the imprint of any one group of professionals, it must be engineers. From the 1880s onward, engineers like William Mulholland and Lloyd Aldrich prescribed bold measures to ease Los Angeles' growing pains. By the 1960s, they had recast the City of Angels as a city of concrete, a metropolis structured around the personal automobile, built to simultaneously tame the excesses of wild nature and correct its deficiencies.
Civil engineers and their creations are the subject of "The Road Taken: The History and Future of America's Infrastructure," a new book by Duke University historian Henry Petroski, himself a civil engineer.
Subtitle notwithstanding, Petroski's book focuses on transportation infrastructure at the exclusion of nearly every other type, including aqueducts, oil pipelines, telecommunications cables, power lines, and the other conduits that, as Petroski writes, "enable civilization to function in a civilized way."
Still, roads and bridges alone provide enough fodder for an author like Petroski, who excels at revealing the origins of everyday, utilitarian things. His previous books include histories of the toothpick and the pencil, and his latest contribution bristles with fascinating details about the elements of road design we often overlook.
Take the stop sign, for instance. When private automobile clubs first erected them in the 1910s to signal "boulevard stops," the signs were diamond-shaped and usually featured black letters on a yellow background. (California's stop signs have nearly always been white on red.) The sign owes its now-familiar octagonal shape to a Detroit police officer who took it upon himself to cut off its corners, thus doubling the number of sides from four to eight. Thanks to international standardization, the work of this police officer is now reproduced around the world.
Curbs and gutters earn their own chapter. So do guardrails and Jersey barriers. Americans' rapid adoption of the automobile in the 20thh century placed great demands on the nation's transportation infrastructure, and engineers responded with such innovations, along with a host of others — yellow centerlines, Botts' dots lane indicators, typefaces designed specifically for directional signs — to keep roads safer at increasingly higher speeds.
Petroski pays particularly close attention to pavements, tracing the evolution of the technology from ancient Rome to the innovations of Scottish engineer John Loudon McAdam, and from the now-ubiquitous asphalt to the self-healing road surfaces of the future. Yes, potholes will one day repair themselves.
But "The Road Taken" is more than a straightforward history of innovation in road design. It argues forcefully that the United States ought to invest considerably more in its public works.
Indeed, the book's title is a play on Robert Frost's famous (and oft-misread) poem "The Road Not Taken," and Petroski suggests that, like Frost's traveler, the United States has encountered a fork in the road — one "representing choices that must be made regarding the nation's infrastructure."
Petroski trumpets the dire warnings of the American Society of Civil Engineers, whose series of infrastructure report cards have given the nation's public works progressively worse grades. In its 2013 release, the category of bridges stood out for its comparatively good mark: C-plus. According to the organization's 2013 report, "Failure to Act," our infrastructure's dismal overall G.P.A. reflects a growing shortfall in public investment.
By 2020, the report projects, the nation's accumulated deficit in infrastructure spending will reach $1.1 trillion. By 2040 it will balloon to $4.7 trillion. Events like the 2007 collapse of an interstate highway bridge in Minneapolis powerfully illustrate the profound consequences of under-investment.
Spending alone, though, will not resolve dilemmas about the social and environmental costs of infrastructure projects.
Cities like Los Angeles no longer anoint engineers as their principal urban visionaries. They now also enlist the imagination of architects, planners, environmentalists and even artists. The poet Lewis MacAdams, for example, reimagined the Los Angeles River Flood Control Channel as a habitat for biological diversity, a recreational space for park-poor neighborhoods and a public commons for the entire city — a vision that now boasts the support of developers, public officials and, crucially, the U.S. Army Corps of Engineers.
Petroski acknowledges the contemporary role of activists such as MacAdams in a chapter on historic preservation, arguing that antiquated infrastructure like Manhattan's High Line can find new, socially beneficial uses. Another provides a tantalizing glimpse of the smart highways of the future, with bridges that detect their own structural anomalies and cars that drive themselves.
But as the 20th century ideal of urban transportation championed by engineers — one that privileged the free movement of the automobile above all else — fades in our collective rear-view mirror, "The Road Taken" says surprisingly little about how to invest in our transportation future while avoiding the road hazards of the past: fractured neighborhoods, polluted air, civic anomie.
Consider the Arroyo Seco Parkway. As Petroski would correctly point out, the road is functionally obsolete, designed for the slower automobiles of the 1940s. At 70 miles per hour, its curves are dangerously tight, its on-ramps laughably short. What, if anything, is to replace the parkway and the obsolete autopian vision it represents?
Today it's hard to see the once-futuristic road as anything but an artifact of the past.
As we speed ahead through the 21st century, we will continue to depend upon the triumphs of civil engineers. We may just ask others to help navigate.
Masters is a Los Angeles historian and host of the television series "Lost LA" on KCET.
The Road Taken: The History and Future of America's Infrastructure
Bloomsbury: 336 pp., $28