Christopher alexander - A pattern language

Therefore:

283

TOWNS

narrow the road to the width of the through lanes only; continue the pedestrian path through the crossing about a foot above the roadway; put in islands between lanes; slope the road up toward the crossing (i in 6 maximum); mark the path with a canopy or shelter to make it visible.

road*♦<���♦ i *

On one side or the other of the road make the pedestrian path swell out to form a tiny square, where food stands cluster round

a bus Stop-SMALL PUBLIC SQUARES (6 I ) , BUS STOP (92), FOOD

stands (93) ; provide one or two bays for standing space for buses and cars—small parking lots (103), and when a path must run from the road crossing along the side of the road, keep it to one side only, make it as wide as possible, and raised above the roadway—raised walk (55). Perhaps build the canopy as a trellis or canvas roof—trellised walk (174), canvas roofs

(244). . . .

55 raised walk*

285

summary of the language

217. PERIMETER BEAMS

218.WALL MEMBRANES

219 . FLOOR-CEILING VAULTS

220 . ROOF VAULTS

221 . NATURAL DOORS AND WINDOWS

222 . LOW SILL

223. DEEP REVEALS

224 . LOW DOORWAY

225 . FRAMES AS THICKENED EDGES

226. COLUMN PLACE

227. COLUMN CONNECTION

228 .STAIR VAULT

229. DUCT SPACE

230. RADIANT HEAT

231 . DORMER WINDOWS

232 . ROOF CAPS

233. FLOOR SURFACE

234. LAPPED OUTSIDE WALLS

XXXI11

. . . this pattern helps complete the network of paths and cars (52) and road crossings (54). It is true that in most cases, pedestrian paths which follow the path network will be running across roads, not next to them. But still, from time to time, especially along major parallel roads (23), between one road crossing and the next, there is a need for paths along the road. This pattern gives these special paths their character.

This cannot be solved by keeping pedestrians separate from cars; it is in their nature that they have to meet, at least occasionally—network of paths and cars (52). What can be done at those points where cars and pedestrians do meet?

On an ordinary street, cars make pedestrians feel small and vulnerable because the sidewalks are too narrow and too low. When the sidewalk is too narrow, you feel you are going to fall off, or get pushed off—and there is always a chance that you will step off just in front of a passing car. When the sidewalk is too low, you feel that cars can easily mount the sidewalk, if they go out of control, and crush you. It is clear, then, that pedestrians will feel comfortable, powerful, safe, and free in their movements when the walks they walk on are both wide enough to keep the

Traditional raised walk in Pichucalis , Mexico.

286

55 RAISED WALK

people well away from the cars, and high enough to make it quite impossible for any car to drive up on them by accident.

We first consider the width. What is the appropriate width for a raised walk? The famous example, of course, is the Champs Elysees, where the sidewalk is more than 30 feet wide, and very comfortable. In our own experience, a walk of half this width, along a typical shopping street with traffic, is still comfortable ; but 12 feet or less, and a pedestrian begins to feel cramped and threatened by cars. A conventional sidewalk is often no more than 6 feet wide; and people really feel the presence of the cars. How can we afford the extra width which people need in order to be comfortable? One way: instead of putting sidewalks along both sides of a road, we can put a double width raised walk along one side of the road only, with road crossings at intervals of 200 to 300 feet. This means, of course, that there can only be shops along one side of the road.

What is the right height for a raised walk? Our experiments suggest that pedestrians begin to feel secure when they are about 18 inches above the cars. There are a number of possible reasons for this finding.

One possible reason. When the car is down low and the pedestrian world physically higher, pedestrians feel, symbolically, that they are more important than the cars and therefore feel secure.

Another possible reason. It may be that the car overwhelms the pedestrian because of a constant, unspoken possibility that a runaway car might at any moment mount the curb and run him down. A car can climb an ordinary six inch curb easily. For the pedestrian to feel certain that a car could not climb the curb, the curb height would have to be greater than the radius of a car tire (10 to 15 inches).

Another possible reason. Most people’s eye level is between 5 1 and 63 inches. A typical car has an overall height of 53 inches. Although tall people can see over cars, even for them, the cars fill the landscape since a standing person’s normal line of sight is 10 degrees below the horizontal (Henry Dreyfus, The Measure of Man, New York, 1958, sheet F). To put a car 12 feet away completely below a pedestrian’s line of sight, it would have to be on a road some 18 to 30 inches below the pedestrian.

TOWNS
Keep the cart below a person's line of sight.

Therefore:

12 feet wide, at least

We conclude that any pedestrian path along a road carrying fast-moving cars should be about 18 inches above the road, with a low wall or railing, or balustrade along the edge, to mark the edge. Put the raised walk on only one side of the road—make it as wide as possible.

18 inches high

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Protect the raised walk from the road, by means of a low wall —sitting wall (243). An arcade built over the walk, will, with its columns, give an even greater sense of comfort and protection -—arcades (119). At the end of blocks and at special points where a car might pull in to pick up or drop passengers, build steps into the raised walk, large enough so people can sit there and wait in comfort—stair seats (125). . . .