Tag Archives: Urban

Building Hybrids

By Fanis Grammenos

Our house types lexicon includes standard, familiar species such as single detached, semidetached, townhouses, walk-ups and apartments. Each of these carries a set of images, an identity, and with it, deeply rooted feelings.  “House,” for example, spontaneously evokes privacy, independence, tranquility, a garden, and, frequently, a happy family and wealth.

These stereotypical associations often misjudge specific samples of homes and places; a “house” can range from a simple abode to an elaborate estate.  The same is true for other types. Some past “townhouses”, for example, were homes to prosperous citizens and were so exquisite that are now coveted masterpieces of domestic design. Prominent public figures raised families in spacious and well-appointed “apartments” at the city center close to their offices. Today, select downtown condominiums provide space, amenities and finishes that only few houses can boast about.

A new type of Townhouse provides privacy and comfort
A new type of Townhouse provides privacy and comfort

Yet there is some basis to the typical reaction and rushed judgement by established residents when they object to certain “types” in their community. Commonly, each type of accommodation has been segmented by district, price range, amenities and, inevitably, by income or lifestyle groups. Walk-ups, for example, usually have no common open space or, when they do, it is a leftover, uninviting, unattended area that detracts, rather than bolsters, overall desirability. Similarly, townhouses are often too narrow for a driveway and a proper entrance, leaving no space to grow a welcoming tree. These drawbacks sustain a stained image but are not inevitable; they can be overcome with ingenuity and innovation.


Breaking the mould and demolishing stereotypes burns creative builders’ candles. Innovators search for adaptations, combinations and fusions. The typical narrow-front townhouse mould, for example, has been broken in at least two ways: by moving the car to the back in a lane-way or by making the lot wider and shallower; both increase house appeal and make economic sense. The next adaptation of the townhouse type includes a fusion and a transformation.  It blends one-storey units with two or three-story ones in groups of six to eight and sheds the boring, unattractive,  endless repetition of identical units in a military row. Each group is crafted to give the appearance of a unique, large Manor House. This fusion attracts a wider range of individuals from different strata, income and life stages, from the young family to the retired couple. One more successfully tested hybrid on the repertoire.

The lines of hybrids keep expanding from the well-used residential tower on top of a commercial ground floor to shopping malls with libraries or universities and to multi-story parking structures with at-grade commercial uses. All these blends increase project viability, street vitality and customer appeal.

But a major fusion has been happening recently in housing types both in function and in appearance. An extension of the reconfigured townhouse is its fusion with the conventional, and usually plain, three-and-a-half storey walk-up. Walk-ups occupy the top rung of layout and construction efficiency and, with it, the claim to affordability. With these two advantages entrenched, the new hybrid blends the merits of the townhouse with this form and opens up new opportunities for neighbourhood site layout.

The new building form creates exclusive pedestrian streets and private outdoor patios

The fusion gives every unit a front door, as in a townhouse, and to the units at grade a front patio for favourite outdoor activities and the occasional neighborly talk. The addition of balconies on the upper floors placed judiciously, gives the assembly the look of a grand villa with a portico.  Finally and crucially the new form acquires urban civility by putting the cars under the building. You might call it a triple fusion except that this new building allows for a fourth: fusing roads with exclusive pedestrian streets. Gone is the asphalt with sidewalk cuts for access to each townhouse garage. In its place, there is a pedestrian bricked path, fully landscaped, free of risk, noise and car fumes; a refreshing experience. Gone also are the miniscule, almost unusable townhouse backyards; they are reborn as a sizable neighborhood park landscaped to accommodate play, rest, contemplation and casual socializing: a breath of community.

The new hybrids in building and neighborhood layout are showing the way to safe, enjoyable and satisfactory living; a living that also has a lighter carbon footprint: the most frequent and pleasant way to move around in such neighbourhoods will be on foot. Due to its modest density, conveniences will emerge a short walk away. And with parents and kids re-appearing in the exclusive pedestrian paths, the familiar image of a car-packed street will fade into memory.

Blending traditional building types and fusing pedestrian streets with common roads, opens the hybrid way to efficient and rewarding neighborhoods.


Church Time : Renovation and Renewal


Canadian statistics about faith and churchgoing show an institution in crisis – a crisis for the church but a real opportunity for communities, developers and builders. Here are some foreboding clouds with a silver lining.

Until 1971 less than one percent of Canadians said they did not abide by any religion. By 2011 the number jumped to 23 percent. Church attendance numbers show the consequences of this sharp rise in faith absence. In 1985 almost 50 percent of women and about 37 percent of men attended church at least once a month. A mere 20 years later the numbers are 30% of women and 25% for men. A similar drop occurred in Quebec in a shorter 10-year period, between 1988 and 1998: from 48% to 29%; almost one fifth of the population discontinued attendance.

The demolished Church on the Hill is reincarnated on the ground floor of an apartment building
The demolished Church on the Hill is reincarnated on the ground floor of an apartment building

This is not a particularly Canadian story. Compare the almost one quarter of Canadians  going to church in 2011 with 5% of Swedes and 3% of Danes;  figures may be low for Canada but it has roughly more than five times the churchgoers of Scandinavia.

With dropping congregation numbers the church coffers can’t match the expenses for running and maintaining their buildings, especially older ones with high heating costs and large maintenance bills due to the complexity of the structure and the labour-intensive detailing that must be respected. Being in financial straits and seeing mostly empty naves, parishes choose the inevitable: closure of buildings and either conversion or demolition.

The United Church of Canada closed more than 400 churches in the last ten years. In Quebec 340 places of worship have been closed, converted or demolished in the same period. All denominations experience the same trend, and the pace of closures is accelerating. Though closures may be inescapable, there is a third, creative alternative to conversion or demolition – renewal.

The opportunity

Just as old houses can be preserved, renovated and change use, so can churches, with the added advantage of a usually central, accessible location and a memorable building image. Old large houses have been turned into fine restaurants, law and consulting offices to mention only a few use changes. But churches with their uncommon, specialized building shell offer fewer options of conversions. The neighbourhood may also object to another restaurant with its evening traffic and required parking.

When conversion is not an option, old houses and other buildings are demolished and the site redeveloped. The logic that applies to churches, however, is somewhat different: Whether conversion or demolition, a community function disappears from the neighbourhood that is essential to its vitality and vibrancy.

Bethel Baptist Church and Seniors Apartments by Robert Reimers Architects (Google Image)

The solution to avoiding this loss? Growing small and combining functions; the same strategy that the post office and banks have adopted: a small counter in a neighbourhood store, and a teller machine practically anyplace.

For a church there is no better union than with housing, particularly homes that are moderately priced for seniors or struggling families. Such a union preserves the function of the displaced building and in many cases can also retain some of its cherished interior elements and decorations that are imbued with symbolism and memories.

Such a rebirth of building and its function benefits all parties. The church continues its spiritual mission in the parish, the neighbourhood gains residents and becomes more lively, the municipality gains additional tax revenue, and the developer constructs a viable, profitable building. With smart, flexible building design and management, the church space can, in time, be used for other community functions planned or unforeseen.

There are many examples of this creative thinking. Combining uses, making unions between compatible and mutually supportive functions creates smart and viable communities. The trend is catching on and you can now see a university attached to a shopping mall (as in Surrey BC), another university on top of a Canadian Tire store (in TO) and movie theatres or municipal libraries also inside a large multi-storey, galleria-type buildings, that house many functions.

The time for transformation and renewal of church buildings is ripe and an obvious opportunity to enrich communities is calling.

Navigation and Legibility


In an earlier article, Beloved and Abandoned, we presented the grid plan, using Portland’s layout, as a historic relic perhaps deserving of attention but clearly unfit for replication in contemporary settings. That, evidently, is not occurring in any case. Several commentators quickly pointed to the supreme legibility of the simple grid as a counterpoint; clearly an indispensible attribute, they said. But is it?

The value of legibility lies in its presumed link to navigation. It is assumed that good legibility makes navigation easier. But does it?  Is a simple, orthogonal geometry aligned with the cardinal directions a necessary condition for easy city navigation? Apparently not, as we shall see.

Though related, the two concepts, navigation and legibility, are quite distinct. One is about an act and the other about a mental construct. “Navigation” and “way-finding” appear interchangeably in architectural and planning literature and they both mean reaching a destination with ease. “Legibility” which originates from text reading, is harder to grasp, but it does relate to a map in the mind, be it a letter, a picture or a configuration of streets. Legibility expresses the ability to project an image and discern its match with what one sees. Navigation as an act could be compared to dancing – a sequence of rhythm-coded steps that is partly or entirely preset and that becomes intuitive.

The first notion to consider in deciphering this puzzle is that navigation, or finding one’s way to a destination, not only predates geometry by millennia, but it is also a basic skill of most sentient, even “non-intelligent,” life. Examples abound from bees to birds to fish and turtles and many more. Closer to home, emotional, and sometimes incredulous, recounting of pets returning from a distant foster home, point to that instinctive ability.

In humans, a few striking examples, first from the non-urban world, show the distinctiveness of the two concepts and the independence of navigation from geometry.

Inuit will trek for many kilometers beyond the base horizon in pursuit of game, often in poor visibility, in what seems an undifferentiated, unremarkable, featureless landscape and, surprisingly to us urbanites, find their way to a destination and back home with astonishing efficiency.  Legibility, understood as a geometric order or map, is entirely irrelevant in this landscape.



Figure 1. The feat of seafaring for thousands of kilometers in the Pacific Ocean without a single navigation aid still astonishes cultural anthropologists and navy captains (image from Wikipedia)

An even more astonishing example comes from Polynesia. For many centuries before they were “discovered” in 1595, the Marquesas inhabitants had ploughed the vast Pacific Ocean in stone-age-tool-crafted open catamarans to trade with and settle in other distant pacific islands. The crew of ten included a captain and a “wayfinder”, two very distinct roles (the wayfinder does not sleep!). Not a single navigational aid existed on board. These seafaring traders and settlers were able to regularly reach distant ports well beyond the visible horizon, often thousands of kilometers away, with accuracy and efficiency that surpassed by far the skills of fully equipped European sailors.  A great captain, Magellan, for example, sailing west from Cape Horn, missed the Marquesas and other pacific archipelagos to land, months later, with a malnourished and decimated crew, on Philippines.  The Marquesas wayfinder “knew” his directions with infallible precision. Nothing could be less “legible” and more disorienting than a vast, featureless ocean during weeks of sailing.  Evidently in this case, legibility, as a geometric construct, has little to do with navigation.

 Figure 2: A typical medieval city street network within a perimeter wall, now a peripheral arterial. Visitors get easily lost in the maze, but not its residents.
Figure 2: A typical medieval city street network within a perimeter wall, now a peripheral arterial. Visitors get easily lost in the maze, but not its residents.

 Figure 2: A typical medieval city street network within a perimeter wall, now a peripheral arterial. Visitors get easily lost in the maze, but not its residents.

From the urban world, examples also show that navigation does not depend on legibility.  Most visitors describe Arab cities such as Fez, and Marrakech or Medieval cites such as Vienna and Martina Franca (Fig.2) or Asian cities such as old Tokyo and Mumbai, as mazes, impossible to navigate even with a map in hand. In each case, the street pattern lacks clear geometry, has no uniformity or repetition, is rarely rectilinear and seldom abides with cardinal directions. Yet for many centuries, the residents of these cities thought nothing of navigating through their streets. Even more surprising, these same labyrinthine streets had no names and house numbers, yet posed no difficulty to reaching destinations.  Intensifying the surprise, are the cases of planned Roman cities with a highly legible orthogonal grid that were transformed into maze-like patterns by their subsequent occupants as if legibility was undesirable.


Figure 3. Old Vienna’s street network is typical of many medieval cities: irregular, idiosyncratic, varied bock sizes and shapes with multiple orientations,  maze-like. (green indicates pedestrian-only  streets) Giving verbal instructions to a destination could be an insurmountable challenge; following them, an impossibility.

If navigation was not an issue in these early pre-urban, non-urban and urban conditions, then the introduction of a simple geometric arrangement of straight streets and repetitive blocks would seem unnecessary for that purpose. In fact, Aristotle, long after Hippodamus drew the famous grid plan of Miletus, argued against his configuration and in favour of the old, “organic”, labyrinthine pattern on the grounds of defence, as did Alberti 1,500 years later. Camillo Sitte made the same case on aesthetic grounds, entirely unconcerned about legibility, having lived in Vienna, (figure 3) a medieval city, and grown to admire many other similar cities, with irregular street patterns.

These examples show clearly that humans on foot, on horses, carts and in boats have been able to find their way to a destination in natural, non-urban and in urban environments unaided by geometry and printed maps. The one presumed outstanding feature of the simple grid, legibility, proves to be unnecessary for navigation and simply an after the fact attribution by post-Guttenberg humans looking at maps.

Fanis Grammenos is a principal of Urban Pattern Associates and was a Senior Researcher at Canada Mortgage and Housing Corporation for over 20 years. He focused on housing affordability, building adaptability, municipal regulations, sustainable development and, recently, on street network patterns. Prior to that he was a housing developer. He holds a degree in Architecture from the U of Waterloo.




Low Carbon Communities

Many speak of the need to measure the sustainability of development projects in order to avoid confusion and prevent the unchecked “greenwashing”.  Sustainability measurements involve aspects such as energy use by housing units, offices, and cars; watershed protection and sensitive land preservation, to list just a few. But while some aspects are relatively easy to measure (e.g. electricity use), others are quite difficult and some almost impossible because they get tangled up with influences that cannot be separated easily; health, for example.

 A community with affluent residents will generally have more cars and, invariably, more cars mean more driving, particularly when there are young children in the household. Some critics would quickly jump to the conclusion that these residents will be less healthy due to the amount of driving and downgrade the community on that score. Research has shown that this may be a hasty conclusion*. The affect of driving on health, if present, may be overwhelmed by the influence of income and education (two of several factors), both of which correlate with better health.  Until there is a sure way of separating the influence of each factor, we can defer the health-via-driving judgement. However, we need to remember that one community element that has been clearly linked to a positive influence on health is the presence of nearby open space – no project could neglect that feature, if it seeks the brand of “healthy”.

Photo Caption: Pedestrian Streets, featuring houses and offices, dominate this new district. All rainwater is collected for local use.

Measuring watershed protection (another item on the green list) is easier, given that rainwater outflow can be calculated using the subdivision plans, weather data and soil conditions. Assigning scores to a project gets complicated, however, when the size of the site enters the picture. Larger sites, usually suburban, have more opportunities to dissipate rainwater than smaller “Centertown” redevelopment ones. Small water retention numbers may indicate serious site constraints rather than lack of effort to green the project; the verdict could not be clear-cut.

We have less difficulty measuring carbon emissions whether they come from house energy use or from driving.  For building energy use, there is plenty of software to do an estimate with a proviso.

Car usage and emissions in seven European projects
Car usage and emissions in seven European projects

 We know that, once the occupants move in, the predictions can be off the mark by as much as 50% or more; the real numbers emerge after occupancy. But the estimate is still a useful benchmark.  For the amount of driving residents do, prediction is close to impossible; we can measure it only after built-out and full occupancy. Claims about a low car-use community any earlier are simply hopeful aspirations.

Yet, unreliable as they may be, trustworthy projections about driving can be made based on precedents for which there are precise numbers; enter the seven European projects described in a recent report*. These are impressive numbers. The simple chart lists the amount of driving in each, the amount in their surrounding district and, for shock value, the driving in some “good” and “bad” Canadian subdivisions.

It shows that these stellar projects made substantial gains in reducing car emissions. Driving dropped by 30% to 60% of the surrounding district’s share of trips. By contrast, and as an indication of the potential for betterment, even the best performers among Canadian suburbs show multiple times the amount of driving of these projects and also their districts. Even the differences among them are telling: they seem relatively unimportant by comparison to the drop that the seven European projects achieve; a 15% reduction in driving, at most, among Canadian subdivisions as compared to a 25% drop of the lowest achiever among the seven European projects. This cross-continent comparison may be somewhat unfair because of the many differences in context but it serves to demonstrate the enormous potential for gains in our communities.

How did the European developers do it? Many tricks come into play but three top the list: a) layouts that promote walking; b) Priority on bicycle networks and c) support for high-quality transit.

Then comes the important element of overall density: Density and quality transit are the chicken and egg question of low driving communities – they cannot be separated; they must come together from day one. This is the one prescription you cannot do without, if the project is to reduce driving.

In Canada, including these and other recommended elements in the plan will not guarantee less driving but, if we take cues from these examples, it may usher the prospective community in the direction of a greener place.

 Fanis Grammenos

Urban Pattern Associates

 * Two articles on driving and health can be found at:

www.planetizen.com/node/53728 and www.planetizen.com/51851.

** The full report on the 7 projects is available in PDF format at:


*** A research report from CMHC:

“Comparing Canadian New Urbanist and Conventional Suburban Neighbour­hoods” (66954)






Innovation in Regulation


Regulation has a Jekyll-and-Hyde, split personality – attentive and autocratic. On one hand it cares and protects, and on the other, it restricts and confines. Abolish it, and watch people begrudge living in a place where everyone makes their own rules. Conversely, few of us wish to live by somebody else’s. Where do you draw the line? There lies the dilemma that many municipalities face when they enact regulations; between ensuring public protection and not limiting the public’s choices; a tricky juggling act.

This dilemma in planning regulations stems from the clash between tradition and innovation, between experience and exploration, and between practices that have worked and techniques that could work. Tradition asserts that something has worked but exploration counters that a new way could deliver better results. Can a balance be achieved between the assurance of past practices and the promise of new?

It can, and here is how Red Deer in Alberta achieved this balance.

A segment of a subdvision plan shows the pedestrian connectors
A segment of a subdvision plan shows the pedestrian connectors

The issue was, and it will puzzle other municipal heads for a while yet, how to give people on foot an advantage in getting to nearby destinations without restricting their choice of a place to live. Resident location preferences have been documented in market surveys which show consistently a strong desire for living on cul-de-sac and loop types of streets. These types are a fairly recent addition to the street vocabulary, but have quickly gained enormous popularity. Distressingly, they come with a disadvantage – they limit the options for walking to nearby places.  Before the car, that limit would have been an unthinkable restriction on movement; no one would want to walk longer than absolutely necessary for a physically exerting errand. With the car around, this disadvantage seems unimportant. But, it still means limiting personal choice. The obvious solution: Return the 19th century pedestrian era plan where no cul-de-sacs or loops could be found. Too simple: such a solution would limit another personal choice – the preferred place to live; hence the need for innovation.

A newcomer to the realm of neighbourhood planning, the fused grid, showed a solution to this riddle. Many developers quickly grasped the idea and embraced the fused grid model for its many advantages and, importantly, for allowing choices for mobility AND for a place to live. A few ventured forward and applied it, but many others, mindful of existing municipal policies, have shied away from it, fearing approval delays. Delays mean unplanned and unwelcome costs; not an option in a competitive market. The result: new ideas go on the shelf, for a while, at least.

A mini-park connects three looped streets – a Fused Grid technique

Smart regulation

Regulating a street pattern, even if it appears ideal, could stifle innovation; it would stop evolution and adaptation to new circumstances. By contrast, regulating the public benefit and choice that patterns should provide, could become a stimulant to innovation. There may be many untried ways of achieving these benefits. A balanced, smart regulation would let them all come forward and become part of the planning vocabulary.

And that where the innovation lies in Red Deer’s approach to regulation found in its Community Planning Guidelines and Standards document. Rather than prescribing “preferred plans” by means of sketches, the guidelines describe “preferred results” or preferred performance. In simple terms, it says that whatever pattern you chose for your plans, mind the pedestrians and do not disadvantage them: use paths or parks or both to shorten their trips.

 Quickly, variety site-specific solutions started to emerge from developers and planners. For example, the City of Saskatoon designed collaboratively and approved a community plan that applies this very idea (drawing 2). The plan shows, in one case, two cul-de-sacs and a loop  converging on a small park; homebuyers get both mobility and street type choice and a bonus – the delight of nearby nature, tranquility and a valuable property. In another approved development three loops converge to a park: choice, sociability, safety and delight are also present in this layout. (drawing 1)

The Guidelines point the way to a pragmatic approach to regulation: one that protects residents’ options and does not restrict design freedom. As more municipalities follow the Red Deer’s leadership, developers will turn a new page and produce walkable, delightful neighbourhoods. The Guidelines have changed the game rules.  And, inevitably, new layout ideas will emerge and propagate.

The Red Deer guidelines can be downloaded here: http://www.reddeer.ca/City+Government/City+Services+and+Departments/City+Planning/Community+Development+Plans/default.htm

Many neighbourhood layouts that meet the intent of walkability  can be found here: http://www.flickr.com/photos/22392855@N08/sets/72157626176042534/


The Transformative Power of Energy


A shocking piece of news recently brought home the formidable potency of energy: over 300 million people in India were left without electricity, all of Canada ten times; chaos ensued. Factories, offices, hospitals, and traffic came to an abrupt and apocalyptic standstill.  The engines of the economy, cities, were silenced.  Losing power to such epic proportions has never been the case in the past and for good reasons.

Up to a century ago, in 1850, men and animals supplied 94% of the world’s energy and 5% came from fossil fuels; a ratio that lasted for millennia; no power interruptions in that scenario. But by 1950, a mere century later, the numbers were reversed: 93% of energy came from fossil fuels and 6% from people and animals. And much of the fossil fuel burned to supply the electricity grid which provides power to 75% of the world’s houses, offices, factories etc. Astonishing, unimaginable things happened in that century and the years that followed and, reportedly, more are in store. About 90% of all inventions since the Promethean fire emerged in these last 150 years.  Why so?

What lies behind this enormous creativity? Ultimately, energy. As more hands are displaced by machines, more brains can switch to nurturing ideas. But a second and equally powerful lever to this creative surge is cities: apparently, the bigger they get the more innovation they generate: doubling a city’s size increases its creativity by 15%. Several cities have doubled a number of times in the 20th century producing a compounding effect.  Cities become beehives of creativity  because they connect people. As different brains interact, more synapses fire, each leading to yet another potential innovation or enterprise. A new tool in the hands of others finds uses unforeseen by its inventor; and the spiral grows exponentially. 

Animals provided most transportation power until the 1900s


The storyline of connectivity between people traces the path of transportation which shapes the city and determines its size. When human and animal power provided all transport, making a connection meant a trip on foot or hoof and a face to face encounter. News spread at walking speed of 5 km/hr; a slow and often arduous process. In that era most cities reached a population around 30,000 people and a size of about 20 minute walk across. News emanated and propagated from the barber shop, the communal water spring, the pub and later, when coffee become common, the coffee shop.  The circle of interaction was small and the ideas local; inventions were also mostly local and stayed local for generations. When the coal-fired steam engine came on board and followed by the electric motor, cities changed dramatically.

Steam-engine trains and electric trams boosted city size at least ten times and now news and ideas  could be had from places weeks away on foot, in just a day; a double benefit for creativity.  Still, relatives, friends and businesses could only talk to one another by letter; long trips were unaffordable for most.  But the beehive was now much larger, more people interacting and the speed of inventions started to accelerate to the point where a US Patents Office director would declare around 1900s “all that could have been invented has been invented”. The news transmission tower was still at a street corner in the pub or coffee shop.  All of that changed when electrical wires became the highway of communication with the invention of the telegraph and then the telephone, radio and television. 

Overnight the creative “city” was as big as the reach of the telephone line or of the radio signal, which had no practical limits.  Important news about discoveries, opportunities and people came out of speakers or screens.  The barber shop, pub and coffee shop talk was demoted to trivial chit-chat, gossip; little gain to be had from it.  The transmission hub moved to a secluded room someplace no one knew; it didn’t matter.  Electricity made connectivity possible without travel by using wires or airwaves; without travel and at the speed of light!

Not only communication was freed of travel, it was soon freed of filtering, control and reach. With the internet and the cell phone everyone is a hub and a receiver of ideas at the same time.  A video story by anybody can reach a million people or more; at least twenty times the foot and hoof city population.  While you teach a trick to someone on line you can learn another from someone else. Anyone’s ideas can “infect” countless unfamiliar people. City creativity was given another rocket booster.

From walking down to the corner to get news and share ideas to being virtually at every corner of the globe without leaving your living room, connectivity has traveled a long way in a hundred years, thanks to the power of electricity. Power is key to a better future.

A Fused Grid Milestone: Red Deer, AB planning guidelines


has been reached in the adoption of the Fused Grid model – embedding its principles in a municipal standards book.


While the fused grid is being vigorously debated in planning and academic circles, as any new idea normally would, an obstacle to its implementation by pragmatic developers remained: municipal policies set on a whimsical view of what constitutes a “good neighbourhood plan”.

Figure 1: A small park serves also as a connector between two streets
Figure 1: A small park serves also as a connector between two streets

A key criterion of merit, that plans are judged by, is connectivity, which means how directly and quickly people can reach their destinations, particularly close-by destinations such as a bus or light-rail stop, a convenience store, a playground or a grade school.

Measuring connectivity can be tricky, and often not required. It can also be unfair to pedestrians. The simplest method counts the number of intersections per unit area. This usually means normal street intersections – streets that are used by cars and pedestrians.

But pedestrians would rather choose other, more direct and safer routes to get to places if they are available: paths, parks, lanes and, in urban environments, side lanes, parking lots, interior “streets”, plus-15 networks or below grade connectors. Counting intersections ignores all these other options, some of which are more pleasant than an often congested, noisy, risky and noxious street environment. 

Figure 2: Three grid-like plans with indreasing number of intersections

Apart from neglecting other options, counting intersections brings in a baggage of associations that slant the judgement of a plan. Because intersections are generally orthogonal, and because they occur most frequently in grid-like plans of older cities, the automatic, but untrue, inference is that a grid would be a better plan because it results in having many intersections. Consequently, non-grid plans are prejudged as unsuitable for good connectivity.

As it happens, more intersections do not necessarily guarantee good connectivity. For example, Figure 2 shows three grid-like plans, each with a higher count of intersections. Plan C with the highest number makes it almost impossible to find a convenient way in the north-south direction.  Where they happen is far more important than their number.

Rather than starting with a a vague notion of the “good plan” or by counting intersections that neglect certain options of movement, why not keep in sight the objective – directness and ease of reaching a destination – and measure the performance of a given plan. 

That is exactly what the Red Deer Community Planning Guidelines and Standards   book does. It says under interconnectivity: Where a dead end street, P-loop crescent or a curvilinear collector roadway increases the distance of indirect travel for alternative transportation modes the neighbourhood design must provide a short cut for these travel modes via park linkages or walkways. A lane is not an acceptable short cut for this purpose.”

Figure 3: A park that functions as a connector displacing a previous street

And it clarifies in footnotes what is meant by each alternative approach to laying out a neighbourhood as, in the case of the fused grid: “Fused Grid Street Pattern: Within a modified grid of expressways and arterial roadways, on the quarter section level this pattern consists of a modified grid of collector roadways and green spaces to connect cul-de-sac ends, thereby improving local level connectivity for non-motorized travel. This helps reduce automobile use for local destinations and improves community livability.”    

In this light figure 4, a Fused Grid neighbourhood pattern illustration, would perfectly match the intentions of the guidelines.  

 Other plans by developers also move in the same direction and accomplish the goal of connectivity as implied in the guidelines – via paths and parks

This innovative code goes beyond stereotypes and introduces performance, not configuration, as the prime criterion for a well-connected neighbourhood.

A sensible lead to follow. 

Choosing a grid, or not

In an earlier article we discussed Portland’s grid flaws, prominent among which was inefficiency of land use.

We looked at Portland’s 200’ by 200’ block in the context of other layout options and, when we compared it on a number of criteria, it did not fare well. New data* on other American city grids, that emerged since, which are analysed here, sheds more light on this assessment and also open an opportunity for refined versions.

We argued earlier that if the merits of the specific Portland grid plan were self-evident to planers or developers, its use would have been expanded in the city beyond the original plating of 1846 and imitated by other cities, neither of which has been the case.

For this analysis, we used twenty city grids that range from a mere 150 by 150 feet, just over one half acre, to the ten acres of the largest American grid of Salt Lake City (660 by 660 feet). These gridiron layouts also span a range of street right-of-ways (ROW) from 30 feet to 120 feet.  The present analysis focuses exclusively on comparing land use efficiency among the twenty grids. It consequently raises the inevitable question as to which would be a suitable candidate for a contemporary “town”, “Planned Unit” or a suburban subdivision, if any at all.

Figure 1: Chart showing the influence of the right-of-way width on developable land.

We did two types of calculations: a) we measured the land use efficiency of each one in the set by calculating the ratio of buildable (or saleable) land to the total land that includes the right-of-ways (ROW) for streets, as platted and b) we did the same calculation by adopting a constant ROW for all in order to see the effect of the grid frequency (street frequency or street density).

Chart one finds Portland as the third least efficient of 20 urban grids with a buildable land use ratio of 59% and an implied 41% of land dedicated to ROWs. This finding confirms the earlier assessment. The trend lines in the chart reveal the inverse relationship of ROW width to the efficiency of land use, as might be expected. What emerges as more instructive however, is the amount of difference between a low performing grid (e.g. Houston) and a high one (e.g. Charlottesville). From the 57% of the former to the 75% of the latter there is an approximate 30% jump in land use efficiency. Such difference would impress any urban planner and would be decidedly a priority for a developer. Each for a different reason is keen in optimizing the yield of land put to urban use: sustainability for the former and economic viability for the latter. Interestingly, the Houston city block is 1.3 times larger than Charlottesville’s, yet less efficient; a counterintuitive fact that lead us to look at the influence of block size.


Figure 2: A chart showing the correlation of grid block size and land use efficiency

Chart two demonstrates the impact of block size after removing the variability among ROWs and adopting a uniform 60’ width for all cities. Portland now appears as the second least efficient grid in the set, confirming again earlier assessments.  The difference in efficiency between it (59%) and Denver’s (71%) is about 20%, not an insignificant gain in saleable land and reduction in infrastructure costs.  (The exceptional efficiency of Salt Lake City is only apparent as we shall see later.) Instructively, Charlottesville migrated from the most efficient in chart one to the third least efficient (below Houston) in chart two, due to the adjustment of its ROW. This chart reveals a strong correlation between block size and land use efficiency; the smaller the block the lower the efficiency of the grid. Looking at both charts simultaneously, the correlations among all three variables become clearer.

Based on this analysis, we can now consider an optimal, simple, open grid; or perhaps not. There may well be other considerations that would suggest abandoning the homogenous, repetitive grid altogether in favour of another type of layout. Endurance, for example: If replication is any indication of merit, the record does not bode well for the simple grids of the set (as can be seen in Google Earth images): Few of the examples in this set show a continuations beyond the original mile square plan; the majority begin to grow in size, change proportions and even geometry. And as for new towns or subdivisions using them as stencils, the current record is empty. In addition to low survival rate, there are also persistent old and new criticisms.

Key planning figures either through theoretical works or by virtue of built projects have denigrated the simple grid and, in some cases, even orthogonal and rectilinear layouts.

Olmstead in the 1800s abandoned orthogonal planning and introduced curvilinear streets that were to become the model for innumerable subdivisions. Camillo Sitte portrays the grid as unimaginative and unworthy of consideration for new towns. Raymond Unwin in his writings and works rejects the simple, open grid, succeeds in ushering the cul-de-sac through the British parliament and lays out plans free of the rigidity and repetitiveness of the simple grid. Serge Salat tells us that “Unwin joins Sitte in recommending a great variety of street widths, which would enhance the specific character of each street. In the design of districts, the interior streets should not be too wide.  Wide streets planted with trees should be reserved to the outer boulevards where they offer the threefold advantage of serving as promenades, ensuring traffic between districts and delimiting the districts”. In other words uniformity of street width diminishes character and inhibits delineation. In the same vein, Lewis Mumford writes a scathing critique of its use in town planning adding that “..The new gridiron plans were spectacular in their inefficiency and waste”. Clarence Stein creates a model that follows in the footsteps of Unwin dismissing the grid as entirely unsuitable for our times. Recent pioneering projects such as Village Homes, Davis ,CA; Seaside, FL; Kentlands,  Gaithersburg, Maryland;  and Laguna West, Sacramento, CA use layouts that abandon the simple gridiron pattern.

Figure 3. A sampling of 3 simple grids and their corresponding percentage of land used for ROWs.

From the very recent perspective of seeing cities as organisms that obey fractal laws (seen in the works of Alexander, Salingaros, Mehaffy, Mashall and Salat), more fundamental weaknesses of the uniform grid emerged. For example we read that: “Making a line straight, or regularizing a street, as 19th century urbanism has often done, eliminated intermediary scales and hence the possibility of geometric interaction and coupling of smaller scales. In other words it killed life. For thousands of years, historical cities avoided straight lines, creating multiply connected rich structures by way of slight discontinuities in relation to straight lines.”(Salat)

The same author infers that the intent that drove the creation of the simple grid may not have been entirely benevolent: “It is only when an absolute power absolutely controls the ownership and use of the ground that the city can conform to a perfectly geometric form, as was the case in the ancient Chinese capitals or the cities of colonial occupation in North and South America”

In the last 20 years, researchers confirmed the heightened risk of collisions that grid layouts engender and the negative role its unfiltered permeability plays in maintaining security and sociability in a neighbourhood.  Also, from a sustainability perspective, the grid plan has been found deficient because of its potential high ratio of paved surfaces; its land waste; its disruption of natural land features and its low operating traffic speeds.

In spite of this evidence against the simple grid and the complete absence of new applications of it, we may still wonder if a simple grid can be chosen on the basis of two known grounds: its legibility and the speed at which it can be surveyed. All simple grids in the set share these attributes irrespective of their size.

Figure 4: The turning radius of a team of four oxen pulling a four-wheel cart determined the width of the streets in Salt Lake City. (Image source: Wikipedia)

Knowing the relative impact of the variables we examined, the choice among grids becomes easier but, heeding the criticisms, also irrelevant. However, an opportunity opens up to manipulate them by selecting desirable elements from each; no need to copy uncritically. For example, the highly unusual, 120-foot ROW of Salt Lake City’s streets (based on the long-outdated need for a team of four oxen pulling a cart to turn around within the street) would be unjustifiably wasteful and unpleasant if used for residential streets, where traffic is low and buildings small. Similarly, its 660 by 660 (10 acre) block size (based on homesteading family units, mostly extinct now) cannot be subdivided efficiently for current two-income-earner family houses. These historic changes in socio-economic structures are in fact reflected on the ground; many of Salt Lake City’s original blocks have been divided in half by a mid-block road. Consequently, its exceptional theoretical efficiency on the chart evaporates in practice and renders the block as found unusable. Clearly, choices should be made with an eye to current socio-cultural conditions.

 Modifying the ROW width can definitely lead to substantial efficiencies, as we saw. Charlottesville shows the way with the narrowest streets in the set (30’ and 40’) and highest land use efficiency (chart 1). But we need not copy Charlottesville. We know many Greek, Roman, medieval and Arab streets to be much narrower, starting at 6 feet and averaging around 15 feet wide. All these streets functioned adequately for pedestrian movement and still do in surviving city centres that date back to original layouts. But, as with the block sizes, current trade, work and transportation modes bear little resemblance to those when these streets were conceived and used; direct copying may not work.

Figure 5: A 6-foot (left) and 12-foot wide streets (right), millennia old, worked well for the foot-and-hoof traffic of their time.

It is plausible that earlier street dimensions might find an application in contemporary networks: Salt Lake City’s 120 width, for example, as a divided boulevard with six lanes of traffic and a 30-foot linear park for pedestrian movement on either side while a 15’-wide Roman street, as a pedestrian-only, landscaped route connecting wider residential streets that are designed for car access. In this vein, efficiency can be matched with purpose.

Figure 6: Savannah’s composite, 13-acre cellular grid, at 55%, and a 40-acre, contemporary cellular grid at 74% land use efficiency. (Plans at same scale)

Breaking the convenient, but unnecessary, uniformity of the 18th and 19th Century American grids would be a first step in recovering the land efficiency mandated by current ecological and economic imperatives. Pointing in that direction, Savannah’s composite, cellular grid includes variable size streets and blocks for private, civic and religious functions. A second step would be to include block sizes that can accommodate comfortably prevalent building types and sizes unknown in the 1800s, again defying block uniformity. A third step would be to adapt its streets for the now universal motorized mobility, of cars, buses, trucks, trams and motorcycles, that is radically different from when oxen, equine and legs shared the transport of goods and people.

In summary, examining the simple grids in this set serves as an introduction to optimizing land use, people circulation and the movement of goods. The resulting challenge is to use these insights to develop patterns that accommodate contemporary urban land economics, transportation, environmental priorities and citizen aspirations as these patterns may have done in their time.

Fanis Grammenos, Director
Urban Pattern Associates

*Credit goes to Daniel Nairn (http://discoveringurbanism.blogspot.com/) for the list of American grids with dimensions.

This article was first published in Planetizen.com


Healthy Travel Modes: Correlations, Causality and Caution

Discussions about the negative influences of car travel as the dominant mode of mobility regularly include its potential detrimental health effects. One example is the association that was recently made between car travel and the lower average healthy life expectancy (DFLE) (by 1.5 years) of US citizens versus their OECD counterparts. The author of the Planetizen.com article cautioned us, however, that “…this is a pretty crude analysis’ and encouraged ‘.. anybody with the skills and time to develop a better model.”

In this vein, and being neither a statistician nor a specialist, I offer a few thoughts that may help refine the analysis or shift its direction.

A short preamble first: Most seasoned researchers acknowledge that stats can almost always provide evidence for what we wish to be true. This is particularly true in social sciences, such as the case at hand. Inadvertently, even with all their mathematical rigour, stats often conceal as much as they reveal (a fact unintentionally made unintelligible in the “study limitations” sections).

To expand the horizon of the health-travel conversation, I explore additional statistics that I believe need to be assimilated into it. These may reveal the multiplicity of factors and their interactions and raise questions about misapplied correlations and improbable causalities.   This article does not aim to deny the merit of proposing policies to increase active travel (a worthwhile goal) but seeks to limit the licence to use statistics incautiously to prove their value. A first step in that direction is to question the appropriateness of longevity (or disability-free life expectancy) as an indicator.  

Longevity and motorization in the US

Life expectancy in the US has risen constantly in the automotive 20th century from 49.2 in 1900 to 77.5 years in 2003 or, simply put, 28 years were added to 50; a stunning cultural achievement.  The same is true for Canada where 31 years were added to 49 since 1901. For a century dominated by motorized transport, which in its early decades caused a virtual slaughter on city streets and, without catalytic converters until the late 70s (combined with a very inefficient fleet), produced a very noxious, toxic environment, this upward trend is counter-intuitive.  Such a trend raises the question of the exact role automobiles plays in the loss of life-years.

The first fifty years of auto-mobility, however, bad as they might have been, are not typical of a general lifestyle that relies predominantly on cars for transport and they could be sidestepped as unrepresentative. The true motorization of daily life took hold from the 50s on, the Interstate Highway era, with the expansion of cities into vast first and second tier suburbs.

A comparison of VMTs and longevity for the 2nd half of the 20th century shows again a fairly good correlation.  In these 50 years, the per capita VMTs in the US rose from about 3,000 miles in 1950 to about 9,000 miles in 2000, an astonishing 300% percent increase. Yet, during the same period 7.4 years were added to the average lifespan of US citizens. Are we to conclude from these figures that motorization aided longevity? Surely not, based just on one covariance.  We don’t know in what ways auto-mobility could mediate a life-span increase, except by the mundane and likely insignificant, speedier access to hospitals for accident victims and heart or stroke patients. Another speculative connection, supported by research, is the opportunity it provides for frequent visits to the countryside, a confirmed de-stressor. Cottages, for example, a cherished possession of about 10% of households, would be entirely inaccessible on weekends or other occasions without auto-mobility. The same holds true for pristine and remote National Reserve sites. Abundant research has shown a correlation between proximity to nature and better population health but we don’t know whether cottage owners or frequent hikers fair better than others. Consequently, lacking the list and the data on the mediating mechanisms, the question of a potential positive influence of auto-mobility and its magnitude remains unanswered for now. And, based on the simple countervailing evidence, neither can we assert that this dramatic three-fold increase in VMTs had a calamitous effect on health or longevity.

Zooming in on mechanisms

On the negative influence side, we can at least speculate on the possible mechanisms (Chart 1). Eight health problems are associated with inadequate physical activity, of which driving is one version.  Of these eight, heart and cerebrovascular diseases have decreased dramatically in the US (down by roughly two thirds since 1950), though they still remain as principal causes. Cancers, of which there are many types and have many, and unknown, potential causes (including a chemical overload in foods, drinks and air), have remained practically unchanged. Diabetes returned to the 1950s level after a drop in the 80s. Respiratory diseases have increased and air pollution could be a partial cause for the increase. (Personal driving, however, is but one contributor to air pollution, at about 60% of the total emissions attributed to transport, which is responsible for about 27.3 % of emissions from all sources; this translates to about 17% of the total.)

 The fifth, and direct, cause of life loss, accidents, also declined substantially.  In the US fatalities fell from 15.91 to 11.01 per 100.000 people between 1994 and 2009; a 42% decrease in a slow but continuing trend. In Canada absolute fatalities dropped from about 3,200 in 1996  to 2,200 by 2009; down by 32 percent in 14 years even though car numbers and VKTs continued to increase.


  Chart 1: Principal Causes of Death in the US – time series 1950, 1980 and 2002

Source: CRS compilation from National Center for Health Statistics (NCHS), Health, United States, 2005 with Chartbook on Trends in the Health of Americans, Table 29.  

 Are we to conclude from these downward trends in disease progression and fatalities that a 300% increase in auto-mobility has no significant impact in aggravating the causes of death?  Or, if it did, speculate that other countervailing factors mask the effect?   Until we fully understand the mechanisms of the onset of these diseases and the precise attribution to factors that trigger their emergence, the jury on how auto-mobility modifies lifespan, whether negatively or positively and to what net extent, is still out.

Of the mechanisms, we know that obesity, an early sign of possible negative health outcomes, can have several triggers acting singly or in concert. One is a sedentary lifestyle and a second is diet. Physically passive tasks include driving but also sedentary work, pastimes and hobbies. Driving has been shown to correlate with the odds of obesity increase as have lack of exercise, education, stress, and food amount and type. Note that the fifties, the highway era, also saw the widespread adoption of television soon to become the key media for communication, politics, advertizing and free entertainment, inducing more passivity at home. The same era also saw an exponential growth of fast food chains that paid little attention to dietary rules. These covariances in cultural traits also imply a respective increase in the probable triggers of obesity aside from and in addition to driving. The exact contribution of each remains undetermined.

On the job scene, during these fifty years, the service sector overtook the production sector in employment. More jobs became office desk jobs, while others increasingly involved more driving (e.g. salespersons, school-bus drivers, pizza delivery etc).  Studies show significantly increased odds of obesity among office workers. Increased odds also correlate well with lower education levels and rise dramatically with stress-induced overeating.  Diet has been shown as a key element in the maintenance of a healthy weight. The Japanese for example, have a very low obesity rate (3.2% in 2003) and are said to owe their highest longevity (81.8 years in 2002) among nations partly to eating predominantly fish instead of red meat. Curiously, just after the war, the same normal-weight Japanese had one of the lowest life expectancies in the world a fact that excludes genetic influences and makes the negative impact of increased auto-mobility, which occurred mostly after the war, a moot point.

If obesity can be shown to correlate well with life expectancy, deciphering the relative magnitude of impact of each of its triggers can help rationalise and prioritize policy responses.  Focusing exclusively or predominantly on driving may sidestep great opportunities for speedy, effective action. However, if Chart 2 were taken at face value, only a tenuous correlation, if any, between obesity and life expectancy can be construed. Other factors may be at work that require a closer look.

The curious case of Denmark

The logic goes that if we walk and bike more and use public transport we should expect to live, on average, longer and healthier lives. As it happens, we can test this hypothesis with a real life example, an OECD member, Denmark.  Of  fifteen EU nations ( Chart 2), Denmark had the second lowest car ownership rates in 2004 (354 per 1000), had the highest walking share of trips, the second highest bicycling rate ( 18% in 2003) the fourth lowest obesity rate at 11.4% (2008)  and a below average fatal accident rate (at 7 victims per 100k pp in 2005 ).  Yet, in 2006, Denmark’s life expectancy was the lowest among the fifteen and identical to the  the US’ (at 77.8years), where active modes of transport are insignificant and obesity rates are about three times (33.8% in 2008) the Danish. Clearly factors other than travel mode choice must be at work.


 Chart 2: Life Expectancy and Obesity Rates in 15 European Countries. Source: OECD report, 2009 with data from 2007 or latest available.

The second leader in walking, bicycling and transit use,  Netherlands, fairs no better than average; 1.5 years lower than Italy which has the second highest car ownership after Luxemburg, an average walking share and third lowest bicycling share (at 3%) and with an obesity rate in the same range.

The converse relationship does not bear out either. Greece ranking fourth in obesity(18.1% in 2008), about 50% higher than Denmark, with the lowest car ownership rate, lowest level of walking among fifteen EU countries and by far the highest fatal accident rate, had an average lifespan of 79.2  or 1.4 years higher than the walking/biking Denmark and the compulsive-driving US.  Similarly, the UK showing more than twice Denmark’s obesity rate has a higher life expectancy by a whole year. Data from two other industrialized countries that are highly motorized add more complexity to the puzzle of presumed correlations. Australia and Canada had an 81.5 and 80.9 years of life expectancy in 2008, respectively; a 2.5 year difference from US and Denmark. (Canada obesity 23.1% in 2004; twice Denmark’s).Can we conclude from these inconsistent and contradictory figures that a correlation exists between level of active transportation, and life expectancy?

A similarly thorny line of reasoning supposes that the action path of more driving in reducing life years is via engendering obesity which in turn leads to chronic diseases. Charts 3 and 4 undermine the driving-to-obesity-to-disease path by furnishing statistics on the incidence of diabetes and heart disease.


 Chart 3: Obesity rates and incidence of diabetes in EU countries.  Source: OECD report 2009 (Belgium- data missing)

Chart 3 shows no correlation between rates of obesity and incidence of diabetes.  UK with the highest rate of obesity shows the lowest incidence of diabetes and conversely the least obese nation, Italy, at less than half the UK rate shows almost double the incidence of diabetes.  Germany with an average obesity rate has the highest incidence of diabetes. Denmark and the Netherlands, the nations with the highest levels of active transport do not vary significantly from the average incidence (6.0), contrary to what might be expected. Clearly, other, unknown mediating factors between obesity and diabetes and, consequently, between driving and diabetes are at work. For heart disease, chart 4 also shows hard to reconcile variances. The spikes and troughs of variations in obesity are not mirrored in the corresponding disease incidence.

The Denmark example would be disquieting, if we took the longevity indicator at face value. It would mean that, if the US were to achieve Denmark’s levels of active transportation, a task that might take several generations of policy implementation, it may arrive at square one of the longevity track. Clearly, longevity seems a poor indicator of the effectiveness of active transport in improving health. We need an alternative, or many.


 Chart 4 : Obesity rates and incidence of heart disease by sex in 15 European countries. (M= men, W=women)

Troubling trends

Another conundrum to ponder is the trends in car ownership, mode share and obesity in countries that are leading the way in active transportation. In the two top bicycle/walk users Netherlands, Denmark car ownership rose by 215%, 178%  respectively in 35 years (1970 to 2005). In the same period, US car ownership rose by 190 %, a similar range, though starting at a higher point. Between 1952 and 2005 Netherlands saw the Bike Kilometres Travelled (BKTs) drop to almost half but still leading Europe. Britain’s BKTs dropped by an astonishing 80 percent in that same period. Netherlands and Denmark saw their obesity rate double since 1988 and the same is true for Sweden yet another leader in walking and biking. These trends are both surprising and disquieting: when people who have experienced the benefits of an active lifestyle abandon it in increasing numbers, the prospects dim for everyone.

Is the rise in obesity in these leading countries caused by increased auto-mobility? We would need a very sophisticated  analysis to isolate its influence.  Are these nations heading in the NA direction while NA is attempting to emulate their highest achievements? A perplexing question worth investigating in detail.

Getting to the fine grain differences

If we can’t explain these incongruities, there are other potential correlations that beg for our attention, interpretation and, possibly, choice of interventions.  For example, differences in life expectancy among States and races.


  Chart 5: Income and life expectancy in 12 States, selected on the basis of their respective obesity ratings.

Chart 5 shows a fairly good correlation between income and life expectancy among specific states that were chosen to cover the gamut of recent obesity ratings from highest to lowest. Yet income by itself   does not explain disease; its effect must be deciphered in terms of its mediating role.

A recent UK study, the Marmot Review, found a 9 year life expectancy and a 16 year DFLE difference between the least and the most deprived citizens. A Canadian Study found a difference in life expectancy between the highest and lowest income quintiles of 6 years for men and 3 years for women. Digging deeper, the research identified one psychological/ biological mediating mechanism – the sense of control of one’s life circumstances. Having less control (choice, options), that comes with lower income, increases stress and weakens the immune system with the consequence that disease finds an easy target.

Chart 6 shows that as incomes rise obesity rates tend to fall, a seemingly counterintuitive trend: a) lower income could well mean less food on the table and b) more manual, low-paid jobs, therefore more calorific expenditure. However, lower income could also imply higher unemployment rates, therefore increased average sedentary life and also increased stress. It can also mean a poor diet regime with predominantly inexpensive but unhealthy foods. Note that the lower incomes and higher obesity rates occur in the southern states where African-Americans form a significant proportion of the population; though still a minority (one region where they form a majority is the District of Columbia, the outlier in chart 5. There has been a constant gap in unemployment between whites and blacks that fluctuated between 5 and 10 percent in the last 30 years. In 2003 African-Americans maintained a persistent life expectancy difference of 6.3 years.  

  Chart 6: Obesity rates and median income in 12 selected States

Compiled statistics break down the overall race difference to specific disparities in ailments such as 34% difference in Cardiovascular diseases, followed by 21.1% difference in infections, and a 10.7% difference in trauma. These are substantial differences.  It seems that, as the picture becomes more fine-grained, it becomes harder to ascertain whether the entire 6.3 year racial disparity or a certain (unknown) portion of it can be attributed to driving.

The  puzzle of childhood obesity

While driving to work or shopping could be a contributing factor to adult obesity, its role may be less clear among children. The US CDC reports that obesity has tripled among children between the ages of 6 and 11 in the last 30 years and has gone from 5% to 18.1% among children of 12 to 19 years of age. These young people, who are not drivers, will soon merge into the adult population seeking an explanation for their handicap. A detailed analysis is needed to accommodate this data into the driving-to-obesity hypothesis.


Predictably, and also inevitably, I used statistics to question conclusions drawn from other statistics and to, hopefully, expose a web of complex relations. I beg for the reader’s leniency if they find I was careless in using them.

We started with the 1.5 year difference in average DFLE between the US and OECD countries and ended up with a conundrum about the meaning of many differences: Differences among states in the US, the race difference, differences among EU countries,  the curious puzzles of US versus Denmark, Denmark and Greece, Denmark and two OECD more auto-dependent nations. We also saw the many faces of obesity and the influence of income, education, job type, sedentary lifestyle, diet and stress could have in triggering it. In addition, we saw obesity being just one of many potential contributors to life threatening ailments.

Each study that looks at specific obesity-generating triggers recommends policies to combat them. Consequently, there is a plethora of potential action plans. Each begs the question of effectiveness, time span and, inevitably, cost efficiency. Few attempts have been made at these questions.

Given these intriguing disparities and unsolved puzzles, the question of meaningful correlations between auto-mobility and health remains wide open to finer grain investigations. The challenge of effective interventions is formidable and pressing. Caution in using the Procrustean bed of statistics is clearly warranted; many hypotheses died on it.

Fanis Grammenos

Few of many sources

1 CRS Report for Congress Life Expectancy in the United States Updated August 16, 2006

Laura B. Shrestha, Specialist in Demography, Domestic Social Policy Division

 2 Table 705. Household Income–Distribution by Income Level and State: 2008Source: U.S. Census Bureau, 2008 American Community Survey; B19001, “Household Income in the Past 12 Months” and B19013, “Median Household Income in the Past 12 Months (In 2008 Inflation-Adjusted Dollars),” accessed January 2010.

3. OECD (2010), Health at a Glance: Europe 2010, OECD Publishing. http://dx.doi.org/10.1787/health_glance-2010-en

4. David R. Bassett, Jr., John Pucher, Ralph Buehler, Dixie L. Thompson, and Scott E. Crouter,2008 Walking, Cycling, and Obesity Rates in Europe, North America, and Australia,  Human Kinetics.

 5. Cynthia L. Ogden, Ph.D., and Margaret D. Carroll, M.S.P.H., Division of Health and Nutrition Examination Surveys:  Prevalence of Overweight, Obesity, and Extreme Obesity Among Adults: United States, Trends 1960–1962 Through 2007–2008  


This article first appeared in www.planetizen.com

Can Money Grow on Trees?

When calculating the cost-effectiveness of any operation economists talk about externalities. Mostly they mean the costs or damages to others either downstream or in the future that are excluded from a calculation.

But are externalities always a cost?   Could they be benefits, unforeseen profits and, if so, how would we know?

To know confidently, we need to do more arithmetic than fits on the back of a cigarette package. Incidentally, that package is a perfect case of an externality, when a nearby smoker inadvertently loads my health bill; he only pays for the costs of cigarette production. Or take the case of the new glass tower whose reflected sunlight caused an overload on the cooling systems of an adjacent building. Could someone have calculated in advance the effect and cost of the additional cooling capacity?  

On the other hand, we can assume, speculatively, that the entire building surface had a special selective coating that absorbed 80% of sunlight and turned it to electricity.  In that case, the math would show a reduction in the cooling load and production of power, two profits, a direct and an indirect profit.

There are many cases of profit-making, of unintended benefits, of positive externalities, if you wish, and, luckily, the complicated arithmetic has already been done objectively, reliably (see reference).

Two of the many design elements in a neighbourhood development, of which the unaccounted ledger lines could be in the profit column, are trees and parks. Usually they are factored in as the necessary cost of compliance with municipal regulations or a cost for an attractive, picturesque streetscape. 

Research and good math now show that they can be moved from the debit to the credit column: they can earn money in the short and long run. They do so in many ways: by cutting cooling and heating costs; reducing water runoff; reducing garden watering; saving on conveyance piping;  stormwater plant load; capturing and storing CO2 and harmful emissions; reducing ambient temperatures and raising property values and the tax base, without including hard to price health benefits.

Here are some rounded figures of what one tree can do in an average year for a house, a neighbourhood, a municipality and the city:

  • Intercept  9,000 litres (2000 gal) of rainfall
  • Save 200kWh of electricity in cooling
  • Save 3 mil Btu  in heating
  • Capture  0.7 kg of four harmful air pollutants (added for simplicity)
  • Capture  200 kg  of CO2
  • Reduce storm infrastructure costs 
  • Reduce storm end-treatment costs
  • Increase property value near a planted space

To turn all these additive benefits into money, let’s take an example of a 16 ha (40 acre) neighbourhood with 400 houses and 500 trees, some on its streets and some in a local small park. We take the available summary calculations and, using averages for simplicity, we get the following figures separated by the beneficiaries: the homeowner, the developer and the city at large (all of us):

Total monetary gain in savings from 500 trees and a small park:

  • The homeowners get $29,000 in reduced heating and cooling costs combined.
  • The city saves $245,000 in infrastructure costs and $200 in water treatment costs
  • The developer gets a share of the upfront savings in  storm water infrastructure
  • The capture of CO2 saves $1200 and is equivalent to removing  100 cars from the road
  • The capture of harmful pollutants saves $2,200
  • The developer earns an average of 16% sale price premium

    Trees add delight to the street but also value to properties


Altogether this neighbourhood would save $267,000 the first year and $32,000 each additional year.  And energy prices go up and the value of carbon increases in trading so will the hidden benefits of this neighbourhood. And we just scratched the surface; more positive outcomes from the avoidance of energy gas production, the water quality benefits the reduced frequency of garden watering and so on the chain continues.

The developer has two additional hidden benefits: An alluring sales pitch and, most likely, faster sales, a critical factor in profitability.

Green profits grow like trees or business, slowly; and they last. No one would plant an olive tree expecting to sell olives a year later. It takes about 10 for the first meagre crop, but the tree can last over 1000 years; it is a long term investment plan; a variety of green chip shares. Same is true for planting trees and creating neighbourhood parks.

These generalized and simplified figures avoid the confusing conditionals that appear in research reports.  They paint the big picture, the order of magnitude of the uncounted benefits. The details may vary in each case. But the overall picture is bright: the veiled currency that has been eluding circulation is green.


Reference: Center for Neighbourhood Technology, 2010: The value of green infrastructure