In the first few pages of his new book Overbuilt: The High Costs and Low Rewards of US Highway Construction, Erick Guerra lays out several essential points.
First, while the originally planned Interstate expressway system was completed in 1992, the pace of highway construction spending since then has not slowed.
Second, though President Dwight Eisenhower intended the Interstate system – officially initiated by legislation in 1956 – to be rural, most of the construction funding went to urban and suburban sections, and nearly two-thirds of vehicle travel miles in the system also occur in urban and suburban areas.
Third, though the length of highways may not be increasing, “There are nearly twice as many lane miles of urban interstate” today as in 1990. (All quotes in this article are from Overbuilt, by Erick Guerra.)
But has 70 years of ceaseless highway oonstruction met the stated goals of relieving traffic congestion and making drivers safer?
On the contrary, “The average time spent in traffic per car commuter increased from twenty-nine hours in 1991 to fifty-four hours in 2019.” Meanwhile, “The US traffic fatality rate is two to four times higher than in Canada or wealthy European countries and has improved much more slowly over time than in peer countries.”
From a political economic point of view, it’s easy to understand one reason the highway system continues to grow: construction companies and their investors expect steadily growing revenues and profits, and successfully prevail on politicians to keep the government funds flowing.
Guerra, an urban planning professor at the University of Pennsylvania, provides another reason: the highway lobby has insisted for nearly a century that more highway lanes were needed to relieve congestion. But since more roadway has always induced more traffic, the battle against congestions is never won.
The only thing to do, then, is to keep on adding more highway lane miles. Just as the US economic system demands infinite growth of GDP, its transportation system demands infinite growth of highways.
This fondness for highways seems to match the view of Premier Doug Ford in my current home – Ontario, Canada. Guerra’s book, however, is US-focused and makes only occasional comparative references to other countries. Yet the lessons that emerge from Overbuilt are valuable for any country or city struggling with car dependency.
“Dan Ryan Expressway bridges over 24th Place in Chicago, seen from Archer.” Photo by Eric Allix Rogers, August 2008, accessed via flickr, licensed under Creative Commons BY-NC-ND 2.0.
A history of contestation
Guerra looks back to the early years of the 20th century to trace the growth of the highway lobby, but most of Overbuilt discusses the period since 1956. In that year President Dwight Eisenhower signed the National Interstate and Defense Highways Act into law, and a massive, decades-long construction program shifted into high gear.
Though the legislation was associated with the Interstate expressways (or “freeways” as they were often termed), Guerra makes clear that the commitment of funding was far wider. Indeed, it had to be. As controlled access roadways, expressways don’t provide direct access to any homes, businesses, hospitals, schools, or parks. The expressway system requires an even more elaborate system of feeder highways, service roads and arterials to connect the motoring public with their actual destinations.
Many of these roads cross state lines, and are referred to as (lower-case) interstate highways. The 1956 legislation funded both Interstate and interstate highways at a rate of 90% federal funding to 10% state funding.
The program also funded the acquisition of land for new or expanded highways.
In urban areas, that land was occupied by homes and businesses. By the late 1950s, “New interstates were displacing nearly one hundred thousand families per year but providing no relocation support.” Disproportionately, highways were directed through Black, Brown and poor neighbourhoods. (See Justice and the Interstates for a close look at the ongoing struggle to rebuild these neighbourhoods and provide recompense for families that lost their homes or businesses.)
The highway program was criticized on other grounds as well. For one thing, the phenomenon of induced demand was evident even seventy years ago. Guerra writes that “As noted by early observers such as [US Senator Daniel Patrick Moynihan and [philosopher of technology] Lewis Mumford, increased traffic was generally the largest and most substantial effect of new highway investments.”
Even without adequate payment for expropriation of urban lands, urban highway building is exorbitantly expensive. Guerra writes that about $2.5 trillion (in inflation-adjusted dollars) have been doled out by the federal Highway Trust Fund since 1956 – with most of that funding going to urban highway projects. The spending continues today. Although the Biden administration’s Infrastructure Investment and Jobs Act (2021) has been widely praised for supporting renewable energy and urban public transit, Guerra writes that the Act will also put “hundreds of billions of dollars into building, rebuilding, widening, and maintaining an already overbuilt roadway system.”
This 1973 photo shows “Heavy traffic on the Dan Ryan Expressway in Chicago Illinois. It is the busiest in the United States with 254,700 vehicles daily, according to figures released in March, 1975, by the Federal Department of Transportation. The Kennedy Expressway in Chicago is the second busiest (not shown) with 234,100 vehicles per day.” Photo by John H. White, October 1973. in the holdings of the National Archives and Records Administration. Accessed through Wikimedia Commons.
Meeting peak demand
Going back nearly a century, the nascent field of traffic engineering developed a method that is still used today to provide a rationale for highway expansions.
That method was to peer into the future and guesstimate what the future car and truck traffic demand will be – not to find ways to reduce that demand, but always to provide enough highway space to meet that demand. And not just “meet the demand” but “meet the peak demand”. And not just meet “peak demand” but “demand in the thirtieth busiest hour projected during the next twenty years.”
Why the thirtiest busiest hour, instead of the twentieth or fortieth or one-hundredth busiest hour? Guerra says the choice was arbitrary, but was codified as a standard nevertheless. But the choice to plan and build highways to meet demand in the 99.98th percentile busiest hour has kept highway builders busy, and made the US ever more car-dependent, ever since. Due to induced demand, however, the new or expanded highways quickly fill up and even the demand during routine weekday “rush hour” stays ahead of roadway supply.
Guerra shows how gas-tax revenues from less-than-peak hours are used to subsidize traffic at the most congested times – the reverse of congestion pricing. Accordingly, he cites congestion pricing as one of the most significant ways to reverse the pattern of overbuilding.
But surely all these roadway “improvements” have led to greater public safety? Many highway engineers will claim success on that front, pointing to a drop in deaths per Vehicle Mile Travelled (VMT). Guerra responds:
“From 1955 to 1980, the fatality rate per vehicle mile had halved. To put it succinctly, Americans were driving nearly twice as much, thanks to wider and higher-capacity roadways, and killing about the same number of people after adjusting for population growth.”
In agreement with engineering professor and author Wes Marshall (Killed by a Traffic Engineer), Guerra believes we should discuss traffic risk primarily on a per capita basis as is done with most other public health hazards. Judged on this basis, the expanding highway system looks like a very bad safety investment:
“The places with the most highways have the most arterials, the most local roads, the most driving, and the most traffic fatalities. Across urban counties, each 10 percent increase in roadway per capita corresponds with about a 4 percent increase in traffic fatalities per capita.”
A looming fiscal crisis
Of course the highway system can’t keep on expanding forever, given the finiteness of land and resources. Guerra writes that “the current transportation finance model is unsustainable and fast approaching a fiscal crisis.”
Thus the first step to ending the pattern of overbuilding is to stop funding new highways, and stop maintaining, and even dismantle, some of the highways now in existence. A second step, as mentioned previously, is congestion pricing.
Better funding for public transit might help too, but Guerra cautions that in most areas of the United States, public transit is nowhere near competitive with cars in terms of travel times and convenience; increased funding may convince very few drivers to switch to transit. Such is the legacy of 70 years of induced car dependency.
He also draws on the distinction between accessibility and mobility to advocate another change:
“Measuring accessibility – people’s ease of getting to the places they are trying to go – instead of mobility – traffic speeds, traffic volumes, and highway capacity – is perhaps the single most important shift that needs to take place to begin to evaluate and assess the impacts of transportation investments properly. Movement and traffic are quite simply the wrong way to measure the transportation system.” p 162
Guerra has done a great job of describing the recipe for overbuilding. But the recipe for converting an overbuilt network into a safe, sustainable transportation system is still being worked out in countries and cities around the world.
Teaser image credit: “Passing over the Dan Ryan Expressway, with a good view of the skyline in the background.” By The West End, August 2008, accessed via flickr, licensed under Creative Commons BY-NC-ND 2.0.