Michael Upchurch, author of the novels “Passive Intruder” and “The Flame Forest,” is the former book critic for The Seattle Times.

Sometimes the infrastructure of the United States seems to be hanging by a thread — or by a much-neglected girder. Average citizens, looking to Europe or Japan, can’t help but marvel at the bullet trains, the sleek transit systems and the bridges and highways that don’t seem to be crumbling quite the way ours are.

They also can’t help wondering: What are we doing wrong?

Henry Petroski provides welcome background to our problems and a prognosis in “The Road Taken.” As the title suggests, he frames his book around lines from Robert Frost’s poem “The Road Not Taken,” concerning the choice an uncertain traveler has to make about the route he will take. Petroski’s chapter on “public-private partnerships: pluses and minuses,” for instance, is captioned with Frost’s words, “Telling This With a Sigh.”

A professor of civil engineering and history at Duke University, Petroski has written books on engineering feats that range from the minuscule (“The Pencil”) to the magnificent (“Engineers of Dreams: Great Bridge Builders and the Spanning of America”). He has a clear eye, a mellifluous prose style and a knack for spicing deep research with personal anecdotes (including some obsessing about the shortcomings of the streets and drainage systems in his Durham, N.C., neighborhood).

"The Road Taken: The History and Future of America's Infrastructure" by Henry Petroski (Bloomsbury)

Our national dilemma, Petroski says, is that the United States now has 4 million-plus miles of increasingly congested roads and bridges, many of them built for an earlier time and in a poor state of repair. “Potholed and traffic-jammed roads mean that it takes commuters longer to drive to and from work; it takes truckers longer to deliver raw materials and goods from mine to plant to supplier to factory to warehouse to store; and it takes everyone longer to pay off repair bills for wheel alignment and damaged suspension systems.” As far back as 1988, the National Council on Public Works Improvement stated, “Our infrastructure is inadequate to sustain a stable and growing economy.”

Not much has changed since then.

Over the past two decades, Petroski notes, the American Society of Civil Engineers has given our infrastructure (roads, bridges, rail corridors, water supply, energy grid, etc.) an average D or D+ rating. Headline-making structural failures — Petroski focuses particularly on the Interstate 35 bridge collapse in Minneapolis in 2007 — haven’t been quite the wake-up call you’d think they would be.

While Petroski sounds Cassandra-like alarms, he also offers informative pleasures. He gives a terrific account of a cross-country road trip young Lt. Col. Dwight D. Eisenhower made with the military in 1919. It took 62 days and left the future president painfully aware of the nation’s lack of a decent road network — an awareness heightened later by his experience of German autobahns during World War II. Hence his strong push for the creation of our interstate highway system after he was elected president in 1952.

More surprising are Petroski’s histories of certain “tools” of the road we take for granted: stop signs, traffic lights, road stripes, Jersey barriers. The first painted pedestrian crosswalk, he believes, dates back to 1911. The present form of the traffic light, with red at the top, yellow in the middle and green at the bottom, wasn’t introduced until 1928 — and wasn’t standardized until 1930. Stop signs were ruled illegal in Illinois in 1922 because they were seen as “a violation of the right of individuals to cross streets,” and their iconic white lettering on an octagonal red background didn’t become standard until 1954. More amusing, the concrete road dividers known as Jersey barriers were — despite their name — first developed in California in the mid-1940s.

For the non-engineers among us, Petroski offers lucid explanations of why roads, bridges and other infrastructure essentials eventually wear down. His insight on what triggers and accelerates the development of a pothole is helpful. His take on the traffic beatings that bridges undergo is sobering: “Every vehicle, and especially a heavy bus or truck, that crosses any bridge causes the structure’s fabric to flex and creates a situation in which so-called fatigue cracks can be initiated and grow.”

If anything, he slightly understates how frequently structural collapses occur in the United States when he speaks of “one major failure every thirty years.” Along with the I-35 collapse, he mentions the crumbling of a portion of New York’s West Side Highway in 1973, the destruction of the Tacoma Narrows Bridge in a 1940 storm, the failure of an Interstate 5 bridge north of Seattle in 2013 when a truck grazed its overhead braces and the earthquake-induced collapse of a span of the San Francisco-Oakland Bay Bridge in 1989.

Several biggies are missing, including the 1983 failure of the Interstate 95 Mianus River Bridge in Connecticut (three people were killed, three injured) and the sinking of two floating bridges in Washington state in 1979 and 1990 during storms (no casualties).

To Petroski, the source of these problems is obvious. “Infrastructure does not take care of itself,” he writes. “Infrastructure demands vigilance.”

The trouble, he says, is that we’re usually oblivious to infrastructure until something goes wrong with it. And even when we’re aware of the problems, the political will and the necessary funding to fix them can be difficult to raise.

Petroski highlights the tangled nature of the interactions between government agencies and public-works projects without providing any clear remedy for their sometimes counterproductive results. He’s more optimistic about technical advances that may improve matters. Those include “self-healing” asphalt and concrete that could eliminate potholes before they happen, wireless monitors that could track bridge deterioration at a reasonable cost and, less convincingly, the advent of computer-navigated cars that, if universally deployed, could save infrastructure costs by eliminating the need for stop, yield and other road signs.

Want to cross that rusty bridge without a driver at the wheel or any traffic lights to guide you?

It may be a brave new world, in more senses than one, that’s coming our way.

The Road Taken
The History and Future of America’s Infrastructure

By Henry Petroski

Bloomsbury. 322 pp. $28