street design

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Street-Oriented Architecture (TPS Ep. 11)

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Places where people like to be ALWAYS have street-oriented architecture. Have you had enough of the blank walls, garage doors, and parking lots along your si...

Perhaps the key distinguishing feature between vibrant urban places and the drab scenes Jim Kunstler once called “the geography of nowhere” is this:

Places where people like to be always have street-oriented architecture. The buildings are engaged with the street in some legible, designed way; there’s an indispensable building-to-street relationship that feels mutually reinforcing.

Anatomy of a main street storefront building

The street space, that “public room,” extends from building face to building face—so the way individual buildings are designed affects, and even creates, the experience we have in that space. Many traditional building types, lot layouts and architectural grammar evolved as they did for precisely this reason; they dependably create a good experience and present each building to its neighborhood in a respectable manner.

For example, porches within conversational distance of the sidewalk give houses a neighborly sociability, and provide an agreeable intermediate layer of space between the fully public street and the fully private interior. On intimate streets of rowhouses, stoops and dooryards leave no doubt about where the front façade of the building is.

The finished floors of most rowhouses in Old Town Alexandria are elevated above the sidewalk level for privacy.

In most cases, an elevated finished floor level on the first inhabited floor is useful because it gives the interiors of rowhouses and ground floor apartments an extra degree of privacy and dignity, offsetting the fact that they are so close to the public realm. If you’re walking by outside along the sidewalk, and the inhabitants have their curtains and shutters open, you might see their chandelier, but you won’t be staring at them sitting on the couch or seeing what they’re watching on television! You won’t feel like an intruder, and they won’t feel intruded upon. But here’s an important caveat: In our times, we also need to be sensitive when applying this traditional detail, by also making accommodations for accessibility and visibility. The traditional elevated finished floor makes access difficult for those in wheelchairs or with mobility impairments, so shared ramps, lifts, zero-step entrances into spaces below the piano nobile, slightly elevated alleys, and roll-in lobbies can all be employed.

Storefront buildings on King Street in Old Town Alexandria, Virginia. Small details of architectural grammar matter.

On commercial and mixed-use streets, well-designed storefronts are the key. Consider the anatomy of a traditional Main Street building. Again, the details of architecture intermediate between the public spaces and the private interiors. Awnings, arcades, colonnades, galleries and other appurtenances help us deal with the sun and rain, but they are also ways the architecture reaches out, engages with, and embraces the street space. On the most successful streets, there’s always a clear front door to each building, facing the street. Having frequent doors along the street reinforces the scene.

On main streets, mixed-use buildings should usually have an expression line just above the ground floor, such as a cornice or eyebrow, forming a base that separates the private upper floors from the public world of the commercial street scene below.

#WhatNotToDo

Now, compare all that to deep setbacks, parking lots in front, or to rows of garage doors and “snout houses,” and to blank walls. This soul-destroying pattern became commonplace in late 20th Century suburbia, yet it’s never been shown to work well at making a people-friendly place or street scene—not even once! By contrast, in traditional urbanism, pleasant streets and street-oriented architecture support each other, time and again. When the streets are hostile, we’ll invariably find buildings retreating from the street, recoiling, turning their backside toward the neighborhood.

#whatnottodo

Chattanooga. Photo: Kenneth Garcia

It’s not a style thing. Every architectural style, including modernism, has fine examples of street-oriented designs.

Street-Oriented Architecture: It’s number 11 on my list of Town Planning Stuff Everyone Needs to Know.  Check out Episode 11 of the series, and please share, comment, and subscribe. --Victor

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The Power of Street Trees (TPS Ep. 10)

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Main Street, Greenville, South Carolina

There’s one detail that makes a huge difference in the public realm, and that’s the humble street tree.

Landscape architect Henry Arnold once said, “Fifty percent of urban design is, street trees.” On a tree-lined street, look up; the canopy forms the ceiling of our shared public room. Arnold wrote, “An urban street without street trees is like a building without a roof.”

Cours la Reine, Paris

Shaping space while lending beauty, order

The Ladd’s Addition neighborhood in Portland

Line street trees up, and something magic happens. A tree-lined street is a deliberate intervention, an ordering of the public space, a statement in the common human language of geometry. It never fails to make a place where more people want to be.

One tree, many benefits

However, street trees are not just about making the place more beautiful and ordering the space, but also:

Shade - They shade our walks and bike rides. Street trees can lower the urban heat island effect, by as much as three to seven degrees Fahrenheit.

Legare Street, Charleston, South Carolina

Value - They make the city more economically potent. Two identical houses in otherwise similar neighborhoods will command wildly different prices, if one is on a tree-lined street and the other isn’t.

Water - They hold stormwater and clean up pollution.

CO₂ - Critically, they sponge up carbon dioxide, a key greenhouse gas tied to global warming, and then they make oxygen—and we breathe that stuff!

Missoula, Montana

Lower Cooling Costs - In summer, trees shade the buildings and that lowers cooling costs, as much as 35%, and they cut glare, leaving a delightful pattern of dappled light on our streets.

Place, Brand - Flowering trees and autumn leaves put on spectacular annual shows, drawing us to these places.

Troy, New York. Kenneth García photo

Warmth - And in winter, in temperate climates, deciduous trees lose their leaves to let light in to warm the sidewalks and buildings.

Traffic Calming - They keep us safer, calming traffic.

Habits can be broken

For part of the twentieth century, the street tree tradition faded amid compacted city soil, bad habits and poor assumptions. Convinced— by examples with meager, incorrect planting pits—that urban trees will never thrive and they’ll die young, decision-makers began to question whether they were worth the effort and expense. Public works officials started trimming budgets with the old line, “We’ll add the trees in a later phase.” Some minimalists, seeing starkness as a virtue, pulled their architecture away from trees into wide-open displays. Some landscape architects and arborists began to oppose traditionally aligned trees with close spacing, arguing that this geometry was too formal and dissimilar from the way certain trees grow in the wilderness, and pointing out that the roots under each tree need substantial space. They were willing to forgo the benefits and visual effects of allowing the upper branches to intersect with those of the adjacent trees and having more continuous shade for pedestrians. During the same period, departments of transportation were focused on speeding up and accommodating more cars rather than slowing them down. So they started to see shade trees as a liability, insisting on flimsy “frangibles” instead of the sturdy oaks, maples and elms customary in times past.

Get the planting details correct

Generous planting areas on the avenues of Chicago, Illinois

The turnaround came as landscape architects like Arnold and others realized that, with the right planting details and species choices, urban trees can indeed thrive. Much depends on the preparation of the hole in which the tree will be planted. For example, for the Live Oaks common on streets here in Florida, one key is not only allowing for a larger area of loosened soil below ground for the primary roots seeking water, but also for a larger open area up top around the tree, where fine hair-like roots seek air and filtered sunlight. Our landscape architect Jay Hood specified an innovative planting system for Park Avenue in Winter Park that freed the tree trunks from tight wells with metal grates and allowed for walkable surfaces to float above the roots and loosened soil below. Those trees have defied all expectations and grown quite tall. Many people are surprised to learn they were planted so recently.

In the last couple decades, new techniques and products have emerged to improve the success of street trees in urban areas where space is tight and impervious surfaces predominate. So-called “structural soil” and underground suspension systems have become common. These allow the roots to spread within loosened soil without ramming into excessively compacted earth, yet they solve the problematic lifting of sidewalks.

Green Blue Urban’s tree root system, undergoing installation in Thomasville, Georgia. Rick Hall photo

On wide boulevards and leafy residential streets where trees can be planted in linear, continuous landscape strips, your crew can dig a long trench for the whole tree line rather than individual circular holes. After planting and backfilling (avoiding too much compacting), this produces a larger area of loosened soil for the roots to explore. Naturally this requires thinking ahead about the alignment of underground utilities, drainage, and other details. Bottom line: Consult a competent professional on the right way to plant your street trees.

Beautiful exceptions: Cour du Commerce Saint-André in Paris, and Calle Malasia, in Buenos Aires’ Belgrano neighborhood

Exceptions to the rule

For all the reasons we’ve reviewed, on most of our streets and in most of our communities, we’re better off with lines of street trees, especially in temperate, moderately humid climates. But there are exceptions to this rule. For example, extraordinarily arid places where water is scarce or costly call for other solutions to supplying shade and visual interest, such as narrow streets with buildings brought closer together and cantilevered architectural elements that encroach beyond the building envelope. Fewer trees can also be best for far-north climates where letting more sun in during the many shortened days outranks having shade on the rare warm day. Even in a sunny place where trees grow easily, we might still opt for a unique, skinny, tree-less street here and there in a neighborhood plan, to diversify the addresses and experiences on offer. There are also many kinds of commercial streets and passages, and not all require shade trees; some replace the canopy effect with suspended fabrics, galleries, or portals; others establish the visual interest with creative signs and artwork or palms or flowers instead of shade trees. With or without trees, we also take care to keep clear lines of sight to signage and storefronts on mercantile streets. In Street Design, we also wrote about the usefulness of what Raymond Unwin called the “lean-in” tree, planted in the adjacent garden instead of within the right-of-way.

As with every other detail in city design, context is crucial.

Standard equipment for great cities

When they’re right, they’re right, which is most of the time—so street trees are not just a decorative frill, something to be cut when the budget’s tight. They’re mission-critical equipment in making good, resilient cities and towns, and that’s why they’re number ten on my list of Town Planning Stuff Everyone Needs to Know.

For more information, check out my TEDx talk (it’s a love poem to street trees), and read what John Massengale and I wrote about “The Seven Roles of the Urban Street Tree” in Street Design: The Secret to Great Cities and Towns, or read Henry Arnold’s classic, Trees in Urban Design.   --Victor

Episode 10 of Town Planning Stuff Everyone Needs to Know is all about street trees. This episode is illustrated with photos, diagrams and video from Yellow Springs, Ohio; Rochester, Buffalo, Brooklyn and Manhattan, New York; Barcelona, Spain; Washington, DC; Guilin, China; Stockholm, Sweden; Chattanooga, Tennessee; Paris, France; Greenville, SC; and Miami, South Miami, Coral Gables, Lake Wales, and Winter Park, Florida. Next episode: Street-Oriented Architecture.

Pont Street, London

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Walkable Street Design: 5 Must-Haves (TPS Ep. 9)

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People first

The latest episode of Town Planning Stuff Everyone Needs to Know is about street design. That’s because all successful towns are walkable, and design is the key to that. Design for pedestrian safety and happiness simply can’t be an afterthought, merely considered—if at all—only after all the automobile-related decisions are already made.

Bologna, Winter Park, and Rome

“Walkability,” in this context, is really a stand-in word for pedestrian friendliness and bike-friendliness and accessibility for all, including folks in wheelchairs or with other mobility challenges. Walkable streets don’t just technically allow for people outside cars, they’re welcoming, attractive, less stressful, and livable. A perfunctory sidewalk right next to whizzing cars or a faded painted stripe indicating a bike lane are definitely not enough.

Main Street, Galena IL

Main Street and its environs, Galena IL

Design is indispensable

We should start with walkability as an essential baseline, and then work our way out to all the other considerations like truck access, parking and the like. That’s because the best streets are more than mere transportation corridors—and more than just functionally walkable rights-of-way. When their designs are artful, these streets become unique addresses, places where people especially want to be. Streets need what Steve Mouzon calls “walk appeal” in order to inspire citizens, ignite commerce, and attract real estate investment. Eminent urbanist Allan Jacobs, who inspired generations with his book Great Streets, pointed out that some thoroughfares can even mature into the ranks of what he termed the “great world streets,” distinctive landmarks that endure and set their cities apart from their peers.

Good or great, streets come in many sizes and designs. Immense variety is possible. Upcoming episodes of Town Planning Stuff describe the eleven fundamental street types, and as we’ll show, there are many, many variations on each.

Commonwealth Avenue, Boston. C. Podstawski photo

Five basic features

While there are many options in street design, we find there are a few must-have features always present in people-first streets. These features dependably draw people—and these are features your elected officials can demand in your town. That demand usually has to come from both the grassroots and from the top. As former longtime Charleston mayor Joseph Riley has said, “The mayor is the chief urban designer of the city.”

Rue St. Jean, Quebec: Shaped, comfortable, connected, safe, memorable

First, good streets are shaped. The street space is given a designed form, like an outdoor public room, with the roadway and sidewalk its floor, the buildings its walls, and, sometimes, its ceiling formed by the tree canopy.

Second, they’re comfortable. In most climates that means shaded in the summer. Street trees, and architectural elements like porches, arcades and awnings, moderate the elements.

Rue St. Jean in the evening

Third, they’re connected. They lead somewhere. The streets that feel like what Kaid Benfield calls “people habitat” are usually hooked into the larger network, linked to the rest of the town.

Next, they’re safe. That means you aren’t stressed out about getting run over by a vehicle, because motoring speed is slower by design. You’re also safer if you have what Jane Jacobs called “eyes on the street.” The safe street isn’t faced by blank walls, but by doors and windows and porches and balconies and storefronts.

Lastly, the streets where people really like to be are memorable. They make lasting impressions because beauty surrounds us and human creativity is on display, in architecture and art and signs and landscape design. An artful spatial design, with composed vistas, ratchets up these powerful impressions.

“Umbrella Sky” on Giralda Street, Coral Gables

Walkable street design: It’s #9 on my list of Town Planning Stuff Everyone Needs to Know. For more information, subscribe to the Dover Kohl YouTube channel, or read the book John Massengale and I co-wrote, Street Design: The Secret to Great Cities and Towns.     --Victor

To illustrate many of the ideas in Episode 9, we used downtown West Palm Beach's premier street, Clematis Street. Here’s a closer look at our design for its reconstruction: Safe, Slow, Curbless, Shaded, Adaptable.