Walkability Factors and Human-Centered Design
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This presentation on Walkability is for a upcoming seminar/charrette hosted by the Town of Collierville, Tn. There is a particular focus on block design as one of the key components of a wlakable neighborhood.
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Walkability Factors and Human-Centered Design
- 1. Walkability It’s a Human Issue! Collierville, TN Seminar. Bloodworth
- 2. Why it matters. 22 out of 100 26 out of 100
- 3. DPZ
- 6. 1250 Ft Chickasaw Gardens
- 7. Permeability
- 8. The Structure of a Sponge: Many, many connections
- 10. Poor permeability increases the distance traveled.
- 11. It’s all about the Block
- 13. 1000 Ft Portland 250
- 15. 1700 2850 Ft
- 16. 700 2000 Ft 2250 Ft Peabody Vinton
- 17. 4580 Ft 5050 Ft 3300 Ft 2250 Ft 2250 Ft 1250 Ft
- 18. 4580 Ft 5050 Ft 3300 Ft 2250 Ft 2250 Ft 1250 Ft
- 19. 1380 Ft 1380 Ft 1350 Ft 1350 Ft 1550 Ft 1350 Ft 1200 Ft 450 350
- 20. 810 ft Average Block Perimeter
- 22. Block Perimeter Poundbury Block Perimeter 600-700 Radius
- 23. NA ? 4500 2500 2000 1600
- 24. Fine Grain It’s a Human Issue!
- 28. Block Face Block length (in feet) Excellent: 250-400 Good: 400-500 Acceptable: 500-600 Fair: 600-800 Poor: more than 800 – TND Design Rating Standards, Version 1.5 (2005)
- 29. Safe It’s a Human Issue!
- 35. Interesting It’s a Human Issue!
- 38. Mixture How do you like your Pizza?
- 43. Downtown Collierville 68 out of 100 Pizza Supreme!
- 53. RDI Example: Pre Neighborhood Connector Route Directness Index can better illustrate “before-and-after” Plan improvements Existing Shared-Use Path Route Directness Index Crow Flight Walk Distance RDI / = Transpogroup 1850 ft 1850 ft RDI: .20 .20 375 ft 375 ft
- 54. RDI Example: Post Neighborhood Connector Route Directness Index can better illustrate “before-and-after” Plan improvements Existing Shared-Use Path Route Directness Index Crow Flight Walk Distance RDI = New Neighborhood Connectors / Transpogroup 375 ft 375 ft RDI: .83 .83 450 ft 450 ft
- 55. The Regional Picture Putting it all together
- 58. Australian Urban Model; Evan Jones
- 59. Credits: Movement for Israeli Urbanism and the J. Blaustein Institutes for Desert Research MICHAEL MEHAFFY, SERGIO PORTA, NIKOS SALINGAROS, YODAN ROFE
- 60. Walkability It’s a Human Issue!
- 61. Additional Slides For discussion if needed
- 63. Block Perimeter Block Perimeter (in feet) Excellent: 1000-1600 Good: 1600-2000 Acceptable: 2000-2400 Fair: 2400-3200 Poor: more than 3200 How long will it take to walk the perimeter of the block?
Hinweis der Redaktion
- Aside from protecting precious natural resources, I believe achieving “Walkability” is the most important factor in creating truly Sustainable communities. Why is it important. A study that examined 98,000 home sales in 15 metro areas indicates that for every percent improvement in neighborhood Walkability, there is a $700 to $3000 rise in home values. In Charlotte, the increase in value was $1,986 for each point. So improving walkability can make a terrific difference in both local tax revenue as well as many other factors including a reduction in obesity.
- There is a long term competitive issue as well. Much of Collierville, for example, has poor walkability ratings. Using a national model, the Byhalia and Powell Rd neighborhood has a Walk Score of 22 out of a possible 100. Collierville overall has a walk score average of 26 which is very poor.
- What are some of the most important aspects of creating a Walkable community? The way the community is arranged – the pattern of the community, is probably the most important. There are many ways to arrange buildings, streets and blocks into an overall pattern. This slide shows most of the patterns. When we think about how likely it is that people will walk in a neighborhood, street and block pattern have a great deal to do with the likely outcome.
- Collectively, streets and blocks can form a neighborhood. It was Clarence Perry in 1923 who focused on designing the neighborhood based on what he felt was a reasonable and comfortable walk distance from one side to the other. Clinton McKensie and Clarence Stein continued the same planning emphasis over the next two decades. This 5 minute radius was picked up again in the 1970’s by a young designer from the Netherlands, Leon Krier. Krier as well as Christopher Alexander have emphasized the need to think about the overall system of building great communities by scaling the design limits to the human – as opposed to the car. This radical thought had a great impact on the young Andres Duany.
- Humans can walk about 1100 feet in a five minute time span, and significant research on retail pedestrian behavior has revealed that about 1400 feet is the absolute maximum people reasonably will walk. In a perfect circular world, the five minute walk describes an area of approximately 80 acres.
- When we think about creating neighborhoods and communities that are sustainable from the point of view of retaining desirability over a long period of time, we have to look no further than the Chickasaw Gardens development that dates from the 1920s. Chickasaw Gardens has a clear, definable center (the lake) and a walk breadth of about ten minutes. Some of you will be able to mentally visualize the dimension. But the best way to understand the measurement is to go walk in your neighborhood, clocking how far you can travel on foot comfortably in five minutes.
- Permeability is a key aspect of walkability when applied to the structure of our communities. When a community is permeable, it is easy to move through on foot, and many destinations can be reached in multiple ways.
- A sponge is a good example of something that is highly permeable to water. It provides many, many ways from water to move through its structure.
- Likewise, the structure of our neighborhoods can either facilitate or impede pedestrian movement. The contemporary suburban model clusters similar uses and isolates them from one another. In this pattern, Collector and Arterials roadways function as automobile sewers, collecting all trips and increasing both pedestrian and vehicular travel distances between uses. Sustainable urbanism, on the other hand, relies on a small block pattern laced together by narrow, slow speed streets that provide much greater access.
- Poor permeability increases the distance traveled – whether on foot or in a car.
- One of the very most important issues in achieving better walkability and permeability involves the design of the block. Block design has received little design thought or attention in the United States since after World War II.
- Rick Hall, a noted traffic engineer, outlines 10 factors that are most important to creating a walkable environment. I would add three more keys, but note that Rick’s most important feature is small block size.
- When we think about the size of blocks with regard to permeability, Portland is a good example of a city which has high permeability. Blocks are quite small, with perimeter block lengths of only 1000 feet. Remembering back to our 5 minute walk distance, this means that you can walk the entire perimeter of a block in less than 5 minutes since most of us can walk about 1,100 feet in 5 minutes. A modest perimeter block length is one of the key features in creating a permeable walking environment.
- When a small task force was working on developing standards for the upcoming Unified Development Code for Shelby County, we looked at over 30 existing neighborhood blocks in our region on Google Earth and recorded both their typical lot size as well as their block perimeter. Here are a few from inside the I-240 loop. What we discovered was that our thoughts about block perimeter varied to some degree depending on the size of the lots. But you can see right off the bat that many of the block perimeters were significantly longer than a five minute walk. All three of these would take at least 15 minutes to walk around.
- Chickasaw Gardens, on the other hand, had both smaller block perimeters and also widely varying shapes.
- We also looked at the heart of midtown Memphis which has retained high desirability for over 70 years. Here are two blocks at Vinton and Barksdale. Note the block face on Carr is about 700 feet long. We will talk about Block Face in a minute.
- Now look at downtown Collierville from a block perimeter point of view. Notice that the Natchez blocks are similar in length to the ones in midtown Memphis, and can be circumscribed in about 10 minutes. But look particularly at the block on the west side of the square. This block is closer to the Portland block pattern and can be circumscribed in about five minutes. Then note that three of the blocks are quite long and not permeable at all. This means it is harden in those areas to actually get to different possible destinations on foot – even though there are many interesting destinations in the vicinity.
- Now look at downtown Collierville from a block perimeter point of view. Notice that the Natchez blocks are similar in length to the ones in midtown Memphis, and can be circumscribed in about 10 minutes. But look particularly at the block on the west side of the square. This block is closer to the Portland block pattern and can be circumscribed in about five minutes. Then note that three of the blocks are quite long and not permeable at all. This means it is harden in those areas to actually get to different possible destinations on foot – even though there are many interesting destinations in the vicinity.
- Here is a quick look at the Neighborhood at Schilling Farms that Bob Dalhoff helped design. You can see that Block Perimeters here are more similar to the small block on the Square and have Block Faces on Winchester of about 450 feet. The Neighborhood at Schilling is highly permeable.
- Here is another project we have been working here in Colliervilleon where the average Block Perimeter is about 800 feet. Highly permeable. So it is possible to achieve much smaller blocks than have been typical.
- Here is the layout for the first phase of Poundbury in Dorchester, England. Leon Krier was responsible for the overall Block design, and this layout is worth a lot of study and analysis.
- The first thing to note is that Krier’s first phase formed half of a neighborhood which had a radius of less than the 5 minute walk. The blue star is the approximate center of the neighborhood and you can see that the radius is typically less than 700 feet. So every part of this is within a very easy walk distance. Further, you will also note that the blocks are incredibly varied in shape, but all have short perimeters. The one highlighted has a perimeter of 970 feet – less than the Portland standard. What this means is high permeability. There are an astounding number of ways to get to different destinations within the neighborhood, both along the primary street network and also through back alleys. Poundbury is probably the most walkable environment I have ever encountered.
- So let’s sum up our thoughts about Block size. This is a slide lifted from the SmartCode. It organizes settlement patterns into varying intensities. You may be able to see the maximum block perimeters shown, but I want to leave you with my own choices be Transect Zone. As urban density and intensity increases, the “take away” is that permeability should correspondingly increase. So my suggested AVERAGE maximum perimeters range from 4500 feet to 1600 feet. If you viewed this chart from the point of view of Collierville’s downtown, its neighborhood would be best of perimeter block sizes averaged no more than 2000 feet. To reach that degree of permeability will take thought and time.
- Grain is another issue I will touch on quickly since it is not frequently discussed. Grain is something the eye perceives, and is particularly affected by the length of a Block Face. Allen Jacobs in his book Great Streets noted that Block Face or Length has a lot to do with why we think some streets great to walk down and other not. Short Block Faces, articulated facades and embellished streets are perceived as finely grained and I believe more desirable.
- Here are two European street examples. The one on the left shows a very long Block Face with a constant cornice line for a significant distance. The one of the right shows a shorter Block Face under construction with much greater articulation in both the building palette and roof line.
- This block in Atlanta’s downtown is well articulated three dimensionally as well as having a reasonable building length.
- This office building in Providence, Road Island, though of constant cornice, is of reasonable length and well articulated on the face of the building. Bottom line, you do not feel overwhelmed as a pedestrian walking along the building as you did in the first slide.
- So some good rules of thumb for Block Face dimensions taken from the TND Design rating Standards. A Block Face between 250 and 400 feet is something to strive for. The next time you are out walking, particularly in a downtown commercial area, think about block lengths that discourage you. Short Block Faces generally means higher permeability and certainly a more pleasant view.
- Safe. If a walk isn’t safe for a pedestrian, no one will want to walk. Safety has a lot of components – you want what Jane Jacobs called “eyes on the street;” you want a buffer to passing cars, and short intersection distances and narrow streets.
- Who would want to cross this intersection. Unfortunately, because of traffic planning philosophies prevalent over the last 40 years, most of our communities have this type of intersections and street system every mile.
- Reducing Block size has the effect of increasing the number of streets in the network. We actually can rid ourselves of 4 lane arterials if we increase the number of small, narrow and slow moving streets while at the same time making a much more pleasant walking environment.
- Here is a safe, nearly perfect pedestrian environment in Providence. Notice the on street parallel parking serves as an important buffer to the pedestrian. The same can be said for the massive street poles. The shops look out to the pedestrian (eyes of the street) and the overall perception is fine grained and embellished.
- Here is a small street in Europe where trees at great frequency are being used to protect the pedestrians on the side walk. However, the street is so pleasant that pedestrians have taken it over as well.
- If it’s not an interest walk, few will walk.
- Even a highly networked environment will not make up for boring or oppressive buildings. Here an effort has been made to liven up what otherwise is a poor walking environment.
- This zone, on the other hand, has a lot of interest, with trees providing shade in the summer but allowing the sun to come through in the winter.
- Really great walking areas within our communities have varied kinds of destinations within them. When you think about a neighborhood, this means avoiding monoculture like a cheese pizza.
- Rather than congregating civic and non residential uses all in one zone, we can disperse them. One of the good effects of dispersal is that destinations are sprinkled throughout a community or neighborhood.
- Here are two alternative plan views of a neighborhood. One disperses uses in a thoughtful and strategic way. One congregates them. Municipalities need to think long and hard about where to put civic and institutional uses.
- Here is another one of Leon Krier’s neighborhood plans where important non residential uses are sprinkled strategically in a community in Berlin.
- The great news for downtown Collierville is that it has a LOT of varied uses already. It’s walk score (remember Byhalia and Powell’s Walk Score of 22) is 68, which is quite good in spite of poor permeability. The Walk Score system puts high value on the different types of destinations within a neighorhood.
- But It is not just civic and commercial uses that need to be sprinkled into our residential areas. Formal open space is another important component in making a neighborhood walkable. This is an aerial of one of the finest cities in the world: London. It is a view of Belgravia and Kensington. Note the incredible number of small parks imbedded in the community.
- Andrew Miller while at MIT researched the economic relationship between parks and house premiums facing the park or near the park. What he discovered was that premiums are highest on the park and fall off rather rapidly so that beyond 600 feet there is no premium. Using this metric, one can define whether a developer (or municipality) is better off including formal open space or not based on whether the loss in revenue from removing developable ground is offset by the increase in lot price. This diagram classes lots based on Andrew’s work, identifying A lots as those on the park, B lots as those within 300 feet, C lots as those between 300 hundred and 600 feet and D lots those lots beyond 600 feet. As long as the A lots can receive a value in excess of 17%, in general it will make sense to allocate formal open space.
- What this means to our theoretical ideal neighborhood is that parks should be at least 950 feet apart, This frequency will allow three per neighborhood.
- The quality of walking can be greatly increased by requiring sections of formal open space in our neighborhoods. Part of the wonder of Belgravia in London is the amazing frequency of formal small parks. This diagram shows the varied shapes and sizes and the actual walk distances between them. One of my greatest walking pleasures is walking though Belgravia where one comes upon another park on average every 600 feet. Quite remarkable.
- How do we measure Walkability in any quantitative manner?
- Here is a diagram of a block showing the concept of how to measure a Block Face. This would be a very fine block if the faces averaged 400 feet or less.
- Slide illustrates the Route Directness Index calculation for a select Origin-Destination pair of dwellings within a hierarchical (non-grid, cul-de-sac focused) neighborhood.
- Slide illustrates the Route Directness Index calculation reflecting enhanced neighborhood connections.
- Finally, it would be ideal if all streets in the neighborhood network, excluding expressways, would be no greater than two lanes wide plus on street parking. On the primary arterials, current design speed standards push for intersections to be widely spaced which reduces access and permeability. When design speeds are reduced, the ideal spacing of intersections narrows, enabling a more robust vehicular network.
- This is a rough concept plan for the standard mile grid which underlies the Memphis region. Primary arterials are spaced a mile apart in both directions. But rather than one major collector road spaced every half mile, Connector Roads are spaced at quarter mile intervals. Additional connection can occur if the design speed on the arterials is reduced to 35 mph or below. This diagram shows neighborhoods based on a five minute radius walk from the center points. Additionally, the pedestrian and economy network is benefited by modulated densities following the transect. As Michael Mehaffy has suggested, the various nodes will be of varying intensities, but follow the primary movement (the arterials).
- The Australian Model is very similar to the preceding sketch. Proximity studies based on Andrew Miller’s work at MIT suggest that the conceptual number of formal open space elements can be supported economically where premiums for home prices on formal spaces are 17 percent higher than values 600 feet removed. This model is a great conceptualization for the Memphis region.
- Mehaffy, Porta, Salingaros and Rofe illustrate a very similar approach though they have overlaid the concept on top of assume natural features and while incorporating transit.
- “ Walkability” is not just about sidewalks. Are there places you can walk to? Examining data from 98,000 home sales in 15 metropolitan areas, and controlling for other relevant factors, each increase of one point on Walk Score’s walkability scale raises home values by $700 to $3000. In Charlotte, the increase in value was $1,986 for each Walk Score point. Improving walkability raises home values by $10-30,000. Because mixed-use development produces big gains in walkability, the findings are evidence of a strong market for mixed-use neighborhoods. Joe Cartwright at Transportation CNU 2009
- “ Walkability” is not just about sidewalks. Are there places you can walk to? Examining data from 98,000 home sales in 15 metropolitan areas, and controlling for other relevant factors, each increase of one point on Walk Score’s walkability scale raises home values by $700 to $3000. In Charlotte, the increase in value was $1,986 for each Walk Score point. Improving walkability raises home values by $10-30,000. Because mixed-use development produces big gains in walkability, the findings are evidence of a strong market for mixed-use neighborhoods. Joe Cartwright at Transportation CNU 2009
- A good aerial illustrating typical spawl patterns where blocks are large forcing extreme vehicle miles traveled to reach a home directly behind another.