Suburban Nation - Andres Duany [100]
—Standard streets, approximately 24 feet wide, with unmarked parking allowed to stagger from side to side;
—Local streets, medium density, approximately 26 feet wide, with unmarked parking on both sides;
—Local streets, low density, approximately 20 feet wide, with unmarked parking on one side;
—Commercial rear alleys, approximately 24 feet wide within a 24-foot right-of-way;
—Residential rear lanes, approximately 12 feet wide within a 24-foot right-of-way?
—Are street geometries based upon a design speed no greater than 30 mph within the neighborhood, 20 mph on local streets?*
—Are unconventional (traditional) roadway geometries—such as forks, triangles, and staggered intersections—provided to calm traffic?
—Are curb radiuses at intersections a maximum of 15 feet—25 feet in rural areas—with a typical measurement of 10 feet at local intersections? (Larger radii are allowed where required by the turning radiuses of emergency equipment, provided that such equipment is the appropriate size.)*
—Are one-way streets—and streets with more than one lane in each direction—avoided in all but the most urban circumstances, with densities of over 50 units per acre? (If four-lane streets cannot be avoided in low-density areas, such streets must skirt neighborhoods rather than passing through them.)*
THE PUBLIC STREETSCAPE
—Do all streets other than alleys and lanes have a sidewalk on at least one side, 4 to 5 feet in width, 12 to 20 feet wide on retail streets (both sides)? (Exemptions are possible in extremely low-traffic or slow-traffic conditions
—Does every non-commercial street include, between the roadbed and the sidewalk, a tree strip 5 to 10 feet in width, of indigenous shade trees planted approximately 30 feet apart, 10-foot minimum height at planting
—Does every retail street include indigenous shade trees planted at an average of 30 feet on center (10-foot minimum height at planting), located in sidewalk-level planters, typically placed in line with the party-walls between shops (optional in the presence of conflicting arcades or awnings)?
—Are street materials simple, with asphalt cartpaths and trowelfinished concrete sidewalks? (Brick sidewalks are unnecessary, but commercial sidewalks should include a four-to-six-foot brick strip connecting the planters, for root health.)
—Are all streetlights, mailboxes, trash receptacles, and other pedestrian obstructions placed within the tree strip, except main street benches, which should back up to building fronts?
—Are all unsightly transformers, lift stations, utility meters, HVAC equipment, and other machinery located not in the front streetscape but at the rear lane or alley?
—Are streetlights of low height and wattage, and provided frequently toward neighborhood centers (approximately 30 feet on center) and less frequently toward rural edges (at intersections only)?
—For neighborhoods that are located adjacent to nature, does the streetscape become more rural as it approaches the neighborhood edge, with curbs becoming open swales and trees becoming less informal in their placement?
THE PRIVATE STREETSCAPE
—Do all retail buildings front directly on the sidewalk, with no setback?*
—Are all shop entrances located directly at the public streetfront (no malls or gallerias), with any rear entrances for employees only?
—Are storefront signs no greater than 24 inches tall (or 24 inches wide if vertical), and blade signs no greater than 12 inches tall (or 12 inches wide if vertical), with translucent signs and sign awnings prohibited?
—Are residential buildings placed relatively close to the street, such that houses are generally set back the equivalent of one-quarter the width of the lot? (This results in shallower setbacks toward neighborhood centers.)
—Do all main entrances present a positive image, rather than being voids between buildings?
—Do the front setbacks permit the encroachment of semipublic attachments, such as bay windows, balconies, stoops, open porches, awnings, and arcades? (Commercial awnings