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The Post-Carbon Highway

“The five and a half million kilometers of asphalt-surfaced roads that make up North America’s highway network have rendered the entire continent accessible to motorists, and have arguably been the single most instrumental factor in structuring settlement patterns and economic development during the last half century.”

By Geoffrey Thün Kathy Velikov RVTR

The 1930s saw the beginning of the construction of this astonishingly efficient strategically engineered system, designed to optimize the logistics of mobility. The infrastructural matrix of the highway system now allows the rapid movement of goods and people throughout North America and supports the growth of a robust just-in-time production and distribution economy. Across the continent, the system’s outward expansion is almost complete. While the twentieth century witnessed the establishment of this fine-grained distribution network and the production of ever more length, planners predict that the twenty-first will be defined by the consolidation of supersized, multicentered urban areas, where the sprawl-related growth and interconnection of proximate centers is creating the emerging megaregions of North America. This recently identified urban form is an agglomerated network of metropolitan areas with integrated labor markets, infrastructure, and land use systems that share and organize interdependent transportation networks, economies, ecologies, and culture (RPA 12; Goldfeld 4). The economic, transportation, ecological, and societal needs and dynamics of the megaregions are proving to be much more complex than a simple scaling-up of adjacent cities and systems. This appears to be a new species of human inhabitation. Indeed, we are on the eve of an era where scale, complexity, redundancy, and multiplicity will be the most urgent considerations for planners working to organize and integrate these new urban regions.

Situation: 401

The Regional Plan Association (RPA), which has been studying the development of megaregions throughout North America, has defined the Great Lakes Megaregion to include the cities of Chicago, Detroit, Toronto, Buffalo, Rochester, Pittsburgh, and Cincinnati. Within this region, Highway 401 is a freeway that runs for approximately 820 kilometers across Southern Ontario from the US border at Detroit through Toronto and into Quebec. It is North America’s busiest highway, and one of the busiest in the world. The section of the 401 that cuts across the northern part of Toronto has been expanded to eighteen lanes, and typically carries 420,000 vehicles a day, rising to 500,000 at peak times, as compared to 380,000 on the I-405 in Los Angeles or 350,000 on the I-75 in Atlanta (Gray). While the United States’ interstate system is a widely distributed network, with multiple routes between primary centers, the 401 is virtually the only line of movement spanning southern Ontario, where 39 percent of the Canadian population and 37 percent of Canadian business is concentrated (Statistics Canada). The 401 splits into tributary highways (the 403 and the QEW) only as it approaches the US border at Detroit and Buffalo. It carries 60 percent of all vehicular trade between Canada and the US. Daily, $900 million worth of goods crosses the Ontario-US border (Ontario Ministry of Transportation), and annually the 401 carries over $1.2 trillion worth of goods to global markets (Government of Ontario, MTO News). Furthermore, it supports the majority of commuter traffic to and from several urban centers, including Toronto and its outlying municipalities.

Pattern Reorganization

The history of North American highway construction is a story of immense political and economic will marked by intense battles between competing visions as well as by fierce fights and tradeoffs over routes, proximity to cities, disruption of neighborhoods, and public expenditures in support of private enterprise. On the one hand, the highway has been positioned as a force for economic and social progress, while on the other it has been cast as a villain bringing environmental damage and the destruction of historic communities.

There are no such tales of friction in the case of the 401. Indeed, the process by which the route of the 401 was established may even be cited as an illustration of an unusually inclusive and democratic planning practice. Planning was underway in 1939 when the outbreak of World War II brought the process to a temporary halt. The Ontario Department of Highways (now the Ministry of Transportation or MTO) took advantage of the construction delay to undertake a survey asking 350,000 Ontario motorists what they would consider the most desirable line of travel from Windsor to Quebec, if such a road were to be built (Shragge).The resulting “desire line” thus established as the route of the 401 followed no existing road or rail line, and its entire length passed well out of the way of many of the settlements that it connected at the time, especially in southwestern Ontario. In fact, the portion that passes through the city of Toronto, known as the “Toronto bypass,” was criticized at the time for being located too far away from the city’s core to allow for convenient access and use (Bagnato and Shragge 93).

It quickly became apparent that the new highway would stimulate urban growth in adjacent communities. An entirely new settlement pattern began to emerge as, section by section, the highway was completed, and proximity became instantly popular, with development responding to this demand. The cities of southern Ontario were all originally located on water and rail access routes, the key determinants of eighteenth- and nineteenth-century settlement and trade patterns. Growth patterns after the construction of the 401 show a definitive movement towards the highway, with the larger municipalities building business parks and residential subdivisions on both sides of the highway’s route, expanding to absorb this line into the municipal footprint.

Critical Capacity

The 401’s desire-line route through a convenient path of least resistance has become a victim of its own success. Three years after the Toronto Bypass had been completed in 1956, it was carrying almost double the volume of traffic for which it had been designed, necessitating an ongoing series of expansion projects. Fortunately, due to its original distance from the city, a 300 meter right of way across the north of Toronto was relatively inexpensive to acquire and has proved invaluable as the 401 expanded multiple times to its current maximum width of eighteen lanes (Bagnato and Shragge 93). Yet, even with such an immense girth, the 401 is currently operating at capacity.

This overloaded artery is a fundamental piece of economic infrastructure. In 2006, an estimated 4.6 million trucks traveled the Detroit-Toronto corridor (Shragge). The 401 is an essential conduit for the automotive industry concentrated in southern Ontario and Detroit; parts are shipped from the US for assembly in Canadian plants and then shipped back across the border in a coordinated just-in-time production system that is a mainstay for the economy of the megaregion and both nations. In 2006 947,000 tons of agricultural products were shipped to the Ontario Food Terminal in Toronto (Belanger and Iarocci 238), which acts as a distribution hub for the entire region, and Toronto shipped approximately 450,000 tons of garbage back into Michigan for landfill (City of Toronto). The 18 million acres of farms in the region use the 401 to distribute Canadian produce globally, and access to the corridor has created North America’s most intensive concentration of greenhouse farming, mediating climate limitations on food production and facilitating rapid distribution of locally grown produce during winter months; 70 percent of the greenhouse produce is shipped to the US (Ontario Vegetable Growers). The 401 carries 448,000 tons of aggregate (MTO 2004, 197) and hundreds of thousands of commuters daily. The highway is an essential infrastructural system, whose operation is critical to almost every aspect of the region’s economy.


Southern Ontario’s population will grow by 30 percent, or four million people, in the next twenty-five years, primarily through immigration. The provincial government’s 2005 plan for growth proposes to concentrate densification in certain urban and exurban centers, the majority of which are located along the Highway 401 corridor, which the report identifies as the major economic driver for the region (Ontario Ministry of Infrastructure Renewal, Places to Grow, 12).

Unsurprisingly, this pattern reflects the developmental trends of the megaregion. The official vision declares that access to mobility and physical connectedness will define a prosperous future, and the logic of densification appears to support that view: capitalizing on existing transportation networks sounds like a good idea, because the cost of maintaining remote physical infrastructures is high. But there is a risk involved in pairing rapid growth and an already congested system within a limited geographical space. The implications may be catastrophic: analysts are predicting that the system could degenerate into complete gridlock in a matter of years. The latest reports indicate that over 15,000 collisions occur on the 401 annually (Gray). Traffic congestion and delays on the 401 are already so severe that they are estimated to cost over $5 billion in lost GDP every year (Places to Grow, 7). In order for the region to remain competitive, new strategies are required to mediate these symptoms of dysfunction.

System Load

Over 71,000 tonnes of salt (NaCl) is dumped on the 401 annually in deicing operations. Fuels and pollutants containing nitrogen, phosphorus, lead, zinc, iron, copper, cadmium, chromium, nickel, and C5H12 contaminate surface water and soils along its length (East-West Gateway Coordinating Council, Table 2). The 401’s original planning located the route in direct proximity both to acres of the most valuable agricultural land in the country and to the drinking water supply of the watershed. The province currently exempts road salt from its environmental protection laws even though it is toxic to plants and animals; a comprehensive study to evaluate the net economic and ecological effect of escalating salt concentrations in ecological systems immediately adjacent to the 401 system has yet to be undertaken. What is clear, however, is that an ever-increasing number of vehicles currently demand the maximum velocity available from the 401, and during five months of the year continuous deicing is essential to road safety.

Dumb System

Architect Keller Easterling has pointed out that, instead of being designed as differentiated, adaptable, and interchangeable, the interstate highways were designed as “dumb networks with dumb switches” (Easterling 77). Like all North American highways, the 401 is a dumb system. It has only one purpose: to allow vehicles to move horizontally on a hard surface. All cars, trucks, and buses, regardless of their size, destination, freight type, or maximum speed, share the space of the highway equally. The asphalt surface systems that connect with the highway give access exclusively to the motor vehicle. Thus, the favored mode of transport becomes the only one possible.

The singular type of access and interface that was built into the original design is the basis for its success, and the “dumb” simplicity of the system has made it the dominant model in North America and around the world. The highway system, combined with the automobile industry, has surpassed all other transportation typologies in the last century.


Every initially simple system, if it is successful, reaches a critical level of complexity at which it begins to fail. Beyond that point, it will need to be retooled and redesigned in order to continue to operate. For the 401, this moment of complexity is imminent. The simplicity that worked so well in the beginning has led to a condition of practical absurdity nearing system collapse. This crisis happens to coincide with the moment when the gasoline-powered motor vehicle also appears to be close to the end of its usefulness, as the plentiful and cheaply accessible carbon-based fuels we have depended on grow scarce. The world is entering a post-carbon energy era.

It was once thought that the depletion of carbon-based fuels would precipitate a decline in mobility coupled with the corresponding demise of the automotive industry, but trends point in the opposite direction. Against all good advice, people continue to rely on their cars, shifting jobs and residences with increasing frequency on the assumption that they can always drive wherever they need to go, and spending increasing amounts of time in transit. Suburban developments are as popular and profitable as ever even as sprawl continues to displace them further and further from employment centers. At the same time, economies are also becoming more and more dependent on mobility as the cost of moving goods continues to decline even as the cost of fuel is increasing. In fact, truck-borne freight is expected to double by 2035 (American Association of State Highway and Transportation Officials, 2007 report, 57). Given these trends, it appears that the road system will not be abandoned and instead will need to be retooled to accommodate new modes of access, interface, and energy delivery to meet increasing demand.

The future of energy is emerging as a transformation from single-sourced fuel to a blended matrix of inputs from a variety of sources, including solar, wind, nuclear, carbon, geothermal, biofuel, and others. The collapse of the fossil fuel system does not mean that the highways will be empty. Rather, the system will have to be reevaluated and genetically redesigned to do more. Simply adding lanes to the existing system cannot avert the crisis facing superhighways like the 401. The post-carbon highway will need to become much more intelligent in how it organizes goods, people, and energy along its length.

Increasing Bandwidth

“Bandwidth” has become a household word; anyone who uses a computer to access the internet is familiar with the term, which refers to the data transfer rate measured in bits per second. When engineers consider the capacity of a highway, they measure the transfer rate of vehicles per hour. When traffic, accidents, or inclement weather slow this transfer rate to unacceptable levels, entire regional economies suffer. In 1998, internet access providers began switching from telephone lines to cable in order to gain increased bandwidth, and thus speed. Most short-distance-communication optical cables comprise what are known as multimode, or multiplex, fibers. These allow multiple wavelengths of light to be transmitted along the same cable bundle. Cable companies call this “increasing power.” What it actually means is that multiple transmissions of light can travel at different speeds, within the same space.

A similar concept can be applied to the post-carbon highway. Instead of having the surface of the highway being universally accessible to all vehicle types traveling at various speeds, the power of the highway would be increased if it were differentiated to accommodate different vehicle types and speeds, in effect becoming a network of parallel, cooperative modes of mobility. A simple version of this scenario exists in almost every North American metropolitan center where faster through traffic (express) is separated from traffic entering or exiting from the urban road system (collector). This differentiation could be further exploited, also separating vehicles by type, size, fuel, destination, and maximum speed. The notion that one surface can serve all is ultimately a naive result of the early days of motorization when private motor vehicles were the primary users of the highway, and transit and shipping used primarily rail or water. Now that the open road is terminally congested, what is needed is a new, intelligent approach to horizontal mobility. In order to optimize the highway’s bandwidth, a variety of transportation types including high speed rail and dedicated vehicle lanes will be configured in a “thick” system where transport types are stacked and separated to maximize speed, safety, and accessibility.

The maximum speed posted on the 401 is 100km/h, but the highway was designed to operate at a much greater velocities, at least 130km/h, and it curves only gently, if at all, for most of its length. The vehicles operated by most drivers are also designed for higher speeds, and the boredom of not being allowed to go faster has been a common complaint among regular 401 travelers. This very aspect of the 401’s design means that it could easily be adapted to include dedicated high-speed travel corridors, providing efficient and rapid long-distance transit.

If the population of the region grows at the expected rate (and the data indicate that this increase is already underway), public transit systems linking this continuous urban corridor will certainly be a viable option, especially if intermodal interchanges, where passengers can easily and efficiently transfer from private vehicles to mass transit, are integrated within the system at key sites. Given the volume of regular freight and just-in-time delivery that currently passes between locations along the 401, a high speed rail (HSR) freight system capable of moving standardized containers should be incorporated. A version of this system is already under development by Siemens utilizing maglev technologies, and includes container and trailer based options.

The post-carbon highway’s innovations will begin with increasing speed, efficient mobility, and interchange with other transport systems, but the changes will not end there. The space of the highway could become further multiplexed with the addition of a self-generated power supply. It could carry main water lines to support growth on its edges. Indeed, the 401 could be configured as a form of mega–trunk line whose primacy within the region is the equivalent of a geologically scaled feature central to the organization of all physical and logistical distribution. The transformational potential of such a radical reimagining of its components is enormous. Beyond its performative capacity as an enabler of distribution, the generous buffer zones of open land on either side of the highway could be strategically planted with species such as staghorn sumac, snowberry, and red-osier dogwood, and combined with chemical separator infrastructure for processing salts and other hazardous vehicle-based oils and particulates, could serve as an immense landscape project with all the traditional scenic benefits to the driver while generating complementary economies and ecologies.

Multimodal Transfer Interchange

As the 401 intensifies, a new typology, the multimodal transfer interchange, will become the key node along the highway and a dominant post-carbon urban construct. These interchanges will be places where the highway and its travelers will be able to interface with its dependent population concentrations. The strategic sites and available footprint for such interchanges are already determined by the logic of the existing system. At the moment, each of the 160 off-ramp interchanges along the 401 simply facilitates changes of speed and direction. Exquisitely engineered choreographic arcs allow individual drivers to negotiate these movements smoothly, but the architecture of each interchange renders unusable an average of 44.3 acres (18 hectares) of surface immediately adjacent to these flows. What if we placed intensively programmed nodal hubs directly on existing exits? These new structures would cohabit with the space of the highway and mediate the increased bandwidth of the system, while forming impressive interior public spaces whose mix of program and transportation confluence could rival the grand railway stations of the nineteenth century and the major airport terminals of the twentieth.

The traditional highway service center with its minimal amenities—fuel station, fast food joint, strip motel—is no longer sufficient. In the post-carbon era of new fuels, a variety of refueling systems will be needed at every service point, each fully integrated with the differentiated modes of travel. Freight transfer points complete with sorting and distribution capacity will facilitate the transfer of goods along the highway’s length. Parking facilities, easily accessible to the transit interchange, will encourage people to leave their cars and choose to take advantage of a faster and far more energy-efficient mode of travel. The transfer interchange will also become a vibrant site for new services, shops, and entertainment for the people living in the multicentered urban region. Fresh food terminals for local organic farmers, daycares, shopping centers, postal and courier stations would connect residents and businesses with the space of the highway.

In a post-carbon era, it is clear that we need to reimagine the potentials of our existing infrastructure systems. Adapting and retooling the 401 into an intensified, complex economic trunk line and as an urban and ecological enabler will yield rich opportunities for new occupations and modes of living in the post-carbon era.


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