The inseparable Twins of Land Use and Transportation

The relationship between land use and transportation sounds like a geeky topic. 

The twins of land use and transportation usually enter our mind as separate subjects: either as transportation or as land use. Likely we would use more tangible terms such as "traffic" in the context ofcongestion or development,or when another forest is cut down for a subdivision. We see no utility to connect the two, so it is only logical that solutions would come separately, too. Too much traffic? Build more or wider roads! New people coming to a region? Build more houses! We may not always like those solutions, but there seems little that could be done about it, right? 

Feedback loop diagram (source:
Jean-Paul Rodrigue, Routledge 2013)

If modern economics began with Adam Smith, modern location economics began with Von Thunen (1826). He was the first to develop a basic analytical model of the relationships between markets, production, and distance. THE GEOGRAPHY OF TRANSPORT SYSTEMS.

There is hardly anything that we experience more often or more directly than land use and transportation, even though we don't think about it. It's just like gravity, which we never think about, not even when we stand on a scale to check our weigh.t Gravity becomes only interesting when it is absent (the floating astronauts in the space station), and land development and roads come into focus when something is unusual. For example, the absence of gas stations and fast food at a highway interchange may strike us as noteworthy. Or a long stretch of roadway near a city where there are no shopping centers, ranchers, mailboxes or subdivisions. 

 

Commercial corridor sprawl

Development cast about along roadways and interchanges is so common that we assume the centrifugal dispersal force that scatters everything everywhere to be as normal as gravity. Until, that is, we travel to small and densely packed countries like the Netherlands, England or Germany and are astounded to see those pristine landscapes often entirely free of development. Where does all this nature come from in a small and densely populated place? Used to seeing all commercial service strung along suburban roadways the tourist travelling in Europe will be even more surprised to find even smaller towns to have a full selection of retail with lots of people milling around. It may dawn on the tourist that a vibrant downtown is the flipside of the protected landscapes,and that the simple act of walking from store to store requires much less space than suburban shopping centers surrounded by parking lots. 

What appear to be simple, not at all complicated linear solutions (more road-space to resolve congestion, more houses for growing  populations) become far more tangled upon closer inspection.

What if someone would turn the normal assumption that development causes traffic on its head and says that a new roads cause development? Or if someone says that more roads cause more congestion? Swapping cause and effect across two seemingly distinct categories or reversing them seems like voodoo trickery.

Yet, those two pronouncements are precisely what many studies suggest. Transportation and land use are entangled in dialectic ways. Many tend to dismiss those non-intuitive findings as ideological propaganda of liberals and tree-huggers or flat-out fabrications of the media, the usual suspects out there to kill the American way-of-life. And that way-of-life includes generous use of space, high mobility and the freedom to build or live where one wants as everybody knows.

To realize the complexity in which the systems of nature and civilization function and interact requires that we take the blinders off that guarantee us the comfortable tunnel vision of expert silos. Only then one realizes that only a few things are what they seem to be and that unintended consequences easily outnumber the intended ones. That building roads can indeed, cause congestion.

Transportation and land use are tied together by a number of factors:

• Loose, low density sprawl development requires larger distances to reach destinations, i.e. more travel. 
• Separating all uses instead of mixing them also requires more and longer trips. 
• "Time is money". Where to live is often decided based on how long it takes to get to work. Maps showing what areas can be reached from a certain point within certain acceptable time-frames like 5 minute walks, 15 minutes drives or transit rides all the way to 1 hour commutes or more show up as isochrone lines. In such a map time is not only distance but also of speed. The faster a connection, the further I can move in a given time and therefore the further away from a job can I select my place of residence. 
• External factors such as land and energy cost influence both land use and transportation and affect the relationship between them. A trip that is reasonable from a time perspective can become unreasonable if gas costs $5 as it does in many European countries. Aaccessible land can become unattainable if it costs a lot.

....community design similar to what developed prior to 1950 can reduce vehicle ownership and travel 20-40%, and significantly increase walking, cycling and public transit, with even larger impacts if integrated with other policy changes such as increased investments in alternative modes and more efficient transport pricing. (Todd Litman, Land Use Impacts on Transport, Victoria Institute, Aug. 2015)

European settlement patterns are clusters

We see,  not only where development occurs influences travel, but also how development is shaped. How development is laid out does not only influence how much space it needs but also affects how much travel is needed. For example, if mobility can only be achieved by one mode (the car), or if one get around in a development on foot, by bike or via transit, whether a street network is redundant (like a grid) or hierarchical (where all branches lead to one trunk) all are factors that affect the vehicle miles traveled per person (VMT). Population growth in a traditional city adds little VMT (The District of Columbia added almost 40,000 residents in recent years but VMT stayed constant). The same growth added to a typical low density US suburbs adds massive amounts of traffic because everybody has to drive, everybody goes longer distances and everybody gets funneled through a few intersections. 

Transportation projects lead to multifaceted forms of economic development impact, which may include effects on employment, income, land use, property values, or building construction. The form of impact varies by the type and setting of the project. (Transportation Research Board)

Now we already have a pretty complex web of factors that link land use with transportation. We can begin to explain why people in Europe have much lower VMT, why landscapes are pristine and why cities are more vibrant there, or why road construction could cause development or even additional congestion. Much has to do with regulatory and economic factors.

American subdivision pattern. Stevensville MD (photo: ArchPlan)

In many parts of Europe farmers cannot simply sell their farm for a subdvision because land use rules would require a complicated sequence of events before land would become development land, with the chief requirement that development has to be contiguous to an existing village or town and that all services are available. No developments are permitted to leap-frog into the country side, no subdivisions without water, sewer and underground electric lines and no developments in environmentally sensitive areas. And even once a new development area is approved, many countries would heavily tax the windfall of such a conversion reducing the motivation for farmers to sell.

European new development would never happen on 2, 3 or even 5 acre lots except for farm-houses. Instead new development would follow principles that we came to call "New Urbanism", it would be clustered and schools, fire-stations and shops would be designed right in the middle of larger developments. Typically, plans would not only require a mix of uses but also building types so that there would be single family homes, apartments, rowhouses, in short a range of options and price points in such a manner that the new developments look a bit like little towns in their own right (unless they are just small extensions of the existing fringe of towns).

Large lot fringe development takes up a lot more space. PFA's are
Maryland's priority funding areas. 

Rarely would developments be approved where the only mobility choice is the car. Even small villages have bus stops, many towns and cities have rail stations. There would always be sidewalks and safe walking routes to the centrally located services. In short, the whole land use planning process is focused on efficiency, small footprint and choice in the mobility options. Thus land use restrictions and zoning make a crucial difference between development patterns in the US and Europe. It is not that Europeans would love their cars any less but they are also really protective of their farmland, forests and other open spaces. Instead of the US pattern where subdivisions and individual homes and businesses string along all types of roadways except limited access highways, Europeans cluster new development contiguous with existing towns and villages. There, rural protection is not achieved through large lot requirements but through prohibiting development altogether except for the farmer's own farm related needs.

Large lot development in Howard County

Whether in Europe or here, if many people make the same decision and move to new development clusters, congestion goes up and speed goes down. Here and there if politicians and road planners  can't resist the itch to add more lanes, they will alter the isochrones and thus open new demand for even more development that was previously too remote. 

The difference is how growth is managed. Land use management prunes the freewheeling real estate market in the name of public interest. Like capacity restrictions and exit requirements in a movie theater, such management protects people from themselves. With such management strategies in place, moving to the countryside is by no means prohibited or impossible. To the contrary, there will actually still be a country side left because denser, clustered developments will leave it open and accessible to everybody. Additionally clustered development will allow the roads to be traveled more efficiently and faster. For un-congested travel, for example, it can be very effective to limit development between nodes and clusters to avoid the many curb-cuts, driveways, intersections and traffic signals that make travel on exurban arteries often such a nightmare in this country.

Most Americans have been fine with a system that lets the market play itself out. We don't want to live in high-rises or any kind of density. We love to be tourists in Europe, but at home cherish large lots, big cars and easy parking. But this edifice of the American way of life begins to buckle under its own weight. The fact that land consumption far outpaces population growth is simply not sustainable in light of a few irrefutable facts pertaining to land and transport:

• The US is still a nation of growth, both in population and economically
• Most US growth occurs now in metropolitan areas, but with a few exceptions most of the growth in metro areas occurs in the periphery of traditional urban cores 
• The middle of the country still empties out in favor of development along the coasts
• Growth in land consumption far outpaces growth in population to a point that in some US areas development in the last 40 years takes more space than all development 200 years before
• Nobody makes additional land. In fact, if anything, land is lost to shore erosion or rising sea-levels.
• Dispersed allocation of growth bankrupts municipalities, counties and States.

Depleted former Baltimore retail dsitrict

Although these matters have been debated for at least forty years, it is still possible for the Governor of the State of Maryland in 2016 to get wide support for a redistribution of transportation funds to building roads and bridges. "Put the money to what people actually use" is his popular line of thinking. It is persuasive since no doubt more people drive than use transit. That this isn't a matter of American DNA but the result of at least 70 years of policies subsidizing dispersal over concentration is conveniently omitted in this type of reasoning.

It is also a type of reasoning that ignores the fact that the two largest cohorts of Americans in the history of the country, the Boomers and the Millennials are pushing back to a more urbanized living, the one cohort out of the necessities of age, the other for being tired of the monotony that comes from dispersal. 

The desire to simply "build your way out of congestion" by constructing more roads is a return to tunnel vision and strictly linear thinking that hasn't worked for 70 years and won't work in the future.

It is the type of thinking that makes the average US citizen use twice the energy of her European brethren and drive many more miles to boot. It is the thinking that not only fouls our air and waterways, spoils our landscapes and has sucked the life out of our city centers, it also makes our public sector and school systems less and less capable of keeping our infrastructure in decent shape. Due to inefficient land use, there is just too much infrastructure to take good care of it all.

Downtown Copenhagen

All this comes to a head in Maryland's recently rekindled debate about the widening of Route 32 in a portion of Howard County that was once designated as the county's agricultural preserve. Howard County, midway between Baltimore and Washington is one of the richest counties in the nation, a recipient of peripheral growth of two national metropolitan power regions. With congestion growing, what is to be done?

Proponents for the road widening argue for less congestion, more safety and yes, for up-zoning of the adjacent lands. Opponents say that the congested road serves as a barrier for opening up the western agricultural preservation zone of the county to development and that such a project violates the smart growth laws of the state.

The discussion about the complex relation of those land use and transportation twins indicates who is right.

Klaus Philipsen, FAIA

Western preserve: Howard County Comp Plan

Links:
Land Use Impacts on Transport, Victoria Institute, Todd Litman
9 Reasons the U.S. Ended Up So Much More Car-Dependent Than Europe (CityLab)

Interactions BetweenTransportationCapacity, EconomicSystems, andLand Use (Transportation Research Board, 12/2015)

Urban Land Use and Transportation, Jean-Paul Rodrigue, Routledge 2013