Review of The Road Taken: The History and Future of America’s Infrastructure by Henry Petroski

Henry Petroski is the Aleksandar S. Vesic Professor of Civil Engineering and a professor of history at Duke University. He has written 18 very popular and highly regarded books on engineering history. Petroski has the unique gift of using case studies to enlighten the evolution of objects ranging from the small such as toothpicks to the large such as bridges. One of his many creative contributions is to convincingly argue that major failures of engineering structures such as bridges need not be considered setbacks, but signals, pointing to where the limits of the present engineering theory and practice are, and thus playing an important role promoting innovations. In his many writings, he underlines the importance of case studies to understand and prevent human error in design.

In his newest, unputdownable book, Petroski describes in fascinating detail the history of North American infrastructure. He puts the spotlight on the more than four million miles of roads and bridges; but in contrast to mainstream authors, he also discusses elements of roads such as centerlines, road signs, and traffic signals. The book’s title refers to Robert Frost’s poem “The Road Not Taken” to address the general issue of making choices without certainty of their long-term outcome. The building of the current infrastructure involved numerous choices such as whether to use asphalt or concrete pavements and white or yellow road lines. The book lays out case studies on roads and bridges, covering their entire lifespan, from inception to operation, taking a close look at the technological, political, and economical context influencing infrastructure choices. The case studies illustrate how choices are made and how correct and false ones result. Thus, the case studies provide valuable insights on courses of action to follow or avoid. Carefully chosen historical drawings and photographs throughout the book illustrate the concepts laid out by Petroski.

In Chapter 2, Petroski explains the origins of the word infrastructure and cites reports on the decline of North American infrastructure due to reduced construction and maintenance for economical reasons. A 2013 report of the ASCE gives the aging infrastructure an overall grade of D+ and estimates the costs of bringing the infrastructure up to shape at $3.6 trillion by 2020. Chapter 3 begins by mentioning tracks stamped by buffaloes, being probably the first “roads” in North America. Then, it goes on to describe how the Romans built their stone-paved roads and how the English word pavement for the hard road surface is derived from the Latin pavimentum. The chapter further describes how modern road design began in France and was advanced by Scottish engineers such as Thomas Telford. In addition, reasons are provided as to why about 94% of North American paved roads are covered with asphalt instead of concrete. Chapter 4 describes the origins of number codes for identifying and signaling roads. Fascinating details are provided on efforts to improve the readability of road signs. Chapter 5 is devoted to how road lines, traffic signs, and three-color traffic signals were introduced. The disputes, delays, and massive cost overruns involved in the completion of the East Span of the San Francisco–Oakland Bay Bridge are laid out in Chapter 6. The next chapter is devoted to the unfortunate elevated highways and the successful New York City subway. Chapter 8 is on the replacement of the Tappan Zee Bridge north of New York City and highlights the role politics sometimes play in large infrastructure projects.

Later in the book, Petroski alludes to Oxford professor Bent Flyvbjerg who estimates that 9 of 10 megaprojects (defined as those costing at least $1 billion 2015 U.S. dollars) have cost overruns. Details are given on the design of road guardrails and barriers: often, they incline their sharp end into the ground, to avoid serious injury to impacting automobiles. Later on, a simple, clear physical model explains the formation of potholes in asphalt roads. In contrast, due to reinforcing steel, potholes are less common in concrete roads. The passages on Petroski’s personal concerns, such as whether to cover his driveway with asphalt or concrete and his frustration with imported tools of low quality are among the most engaging, since the reader can straightforwardly relate to them. A later chapter underlines the importance of well-timed maintenance in order to avoid future costly repairs amounting to four or five times the total required for maintenance. For example, the costs of asphalt roads are often lower than those of concrete roads; however, due to pothole repairs, asphalt roads can be costlier in the long run. The book would not be complete without a chapter on fraud and corruption on infrastructure projects. However, fraud and corruption are not prevalent in North America.

One of the topics discussed in Chapter 18 is the economic relevance of infrastructure. The ASCE estimates that investments in the order of $157 billion per year are needed for infrastructure. Because the demolition of large, aged bridges is often costly, they are sometimes changed to charming pedestrian structures. The next-to-last chapter is on public-private partnerships, intended to attract private investment in public infrastructure. Opponents of public-private partnerships argue that they provide disguised subsidies to private investors. The book concludes with a chapter on “smart” self-driving cars and infrastructure such as bridges that use sensors to warn of growing cracks and self-healing asphalt to automatically repair potholes. In the closing pages, Petroski reminds that the decaying infrastructure leads to longer transportation times, higher fuel consumption, and therefore, higher product prices. Thus, in addition to increased safety, an adequately maintained infrastructure offers major economic benefits.

In this highly valuable and readable book, Petroski brings many carefully selected and thrilling case studies from the evolution of infrastructure to help us understand and rise to the challenges posed by current infrastructure. The detailed case studies make the book an exciting read for all readers, not only those interested in construction. The book will be highly appreciated by American and non-American readers alike, since similar technological, political, and economical forces shape the development of infrastructure in many countries.