As we saw in the first article of this series, building density in an area (and therefore people density), is closely related to the amount of things that can occur on it. But if they happen… where do they happen? A priori we could say that there are two possibilities: in the private space (either your living room or your garden plot) or on the street you find when you leave your home. As you can imagine the fact it happens in one place or another clearly affects urban sustainability in the city where you live.

Let us imagine that we live in a suburb on the outskirts of the city. If again today you want to visit Roberto (the only colleague who lives there) you drive because it takes you less, you do not get tired, do not sweat … let’s admit it is easiest to go driving with the air conditioning at 18 ° C and listening to the radio. However, this morning is not too sunny and you want to walk instead. What would it happen along the way?

Typically not find anyone. No one walks through those little streets which are all paved. You walk in the middle of the road … nothing happens, nothing passes by, and only if a car comes occasionally give a jump to a tiny sidewalk to automatically return to the road afterwards. The street is for the car, not for you to walk on it. It is not a place for meeting, playing or chatting… for that you already have your house’s garden (or your friend’s). The street is a place of transit to get from point A to point B, and if you drive much the better. Furthermore, there are no squares or public gardens; instead we have my garden and, what is more, with a swimming pool!

What if you live in a neighbourhood inside the city? As we said in our earlier history, given the amount of people who live or work there, it’s easier to make things happen when you walk through the streets. Density is the precondition for this to happen, but it’s not the only one, there are many more. Some of them (we’re talking about today) are the answer to the question: How is the street where you go to buy bread?

To get to the bakery I have to go down the street, turn left and turn right second. Along the way, it’s pretty short, I stand to see an ad in the appliance store next door, but I cannot stay long because the child’s stroller is blocking the way. I keep walking and I meet Manolo, my father’s old friend. As again I am blocking the way, I suggest him to move to the corner where there is a small chamfer, a tree and a bench where we can sit down so that he can tell me about his whereabouts. After fifteen minutes of conversation we said goodbye (until I find him again another day) and I’m walking down the narrow sidewalk until I get to the bakery. To come back home I change the path, because the hardware store is on my way. I come back along the street above, where the sidewalk is wider as some time ago the parking spaces were removed. Since then, plenty of terraces invade the sidewalk as many cafes and bars have opened. After purchasing basic DIY material I stopped at one of the terraces next to which there is a playground where my little son meets a friend from school. The sidewalk where we sit is separated from the asphalt by a small wooded strip that keep us away from cars and provides a bit of perfect shade at this time of the morning. After finishing our pints on our way back home through the park my kid meets some friends who are playing football. We stop again for 5 minutes while they are disputing a kind of imaginary world championship. This is a Saturday morning like any other.

Therefore, a trip scheduled to buy a loaf of bread which in theory could have taken just 5 minutes, has become a whole morning. Yet it has not happened the same on the way back. Apart from the chance to meet with the right people, the difference also lies in finding them in the right place. Unlike the typical street where almost everything is asphalt, wide sidewalks enable situations beyond walking: chance encounters, game, staying. Our streets may change and therefore what happens in them too. There are many examples showing that this change is possible; eg Curitiba Rua das Flores and the work of Jahn Gehl and his team in Copenhagen, which is transferred to other cities like Melbourne or action in the now popular district of Gracia in Barcelona.

This second story is very different from that with which we began talking about the urbanization. Someone might say that the solution in that case could be providing the streets with wide sidewalks so that the mere transit becomes something else. But, who would enjoy that “something else” if only few people live there and those who live have their own garden? The answer is obvious to anyone. Then it is important to remember, as we said before, that density of building and people is a precondition. There is no point in increasing the size of the pedestrian space if no one will use it.

Let’s see then how the quality of public space affects the sustainability of the same district, our second story:

ENVIRONMENTAL SUSTAINABILITY. The existence of wide sidewalks, especially in urban centres implies a decrease in the presence of car, one of the greatest actors of greenhouse gas emissions. However, you cannot get rid of the car magically. In parallel it is needed to develop policies for sustainable urban transport (but that’s another story). Furthermore, this pedestrian space as we have seen may allow the introduction of vegetation to increase biodiversity in our cities. However, the simplest explanation is that spending time on the street uses a lot less energy and produces less greenhouse gases than spending time in the car from one place to another.

SOCIAL SUSTAINABILITY. As we have seen already, the existence of pedestrian spaces -so typical of Mediterranean cities- will enable the emergence of new meeting places.

ECONOMIC SUSTAINABILITY. In comparison to the mall as the only option, the intensive use of public space for most of the year creates the most significant axes and commercial areas of our cities.

CULTURAL SUSTAINABIITY. This use of public space beyong going from one side to the other is somewhat typical of Mediterranean culture. The vitality of our cities, perhaps our greatest asset, is based precisely on the continued, varied and intensive use of the street or plaza.

Now let’s see how SUSTAINABILITY INDICATORS are able to measure some of the qualities of public space on which we have spoken. Yet it is important to make a clarification: the fulfilment of these “numbers” in any case does not ensure the success of an urban area. The values ​​below assure optimal conditions for a rich and varied public space, but its success depends on many other factors, some of which are qualitative and therefore difficult to measure (the answer is not only in the numbers). Therefore the question we intend to address is:

How is the public space of the neighborhood where we live?

And the Ecological Urbanism “measures” it in several ways:

· The first parameter (STAYING SPACE PER INHABITANT) measures the amount of space (m2) where other things can happen besides moving. As such one can compute both staying spaces (squares, gardens, beaches, etc …) and spaces linked to the street (pedestrian roads, boulevards, promenades and sidewalks with widths over 5 meters).

In the urbanization model of which we spoke at the beginning, these places are scarce and often found with minimal sidewalks and squares or gardens absent (as most social relationships occur within the plots or the commercial malls). So it is not unusual values of ​​0 m2 / inhabitant in this type of urban developments. On the other hand, while in the second case the shortage of public space is also usually a big problem for the excessive presence of the car, projects aimed at increasing pedestrian public space can significantly heighten the existing values ​​in our cities. Thus, although we can find areas where also nulls are achieved, it is not surprising that values ​​of type 1-5 m2 / inhabitant are found. A reference value is estimated that a city should find more than 10 m2 of staying space per inhabitant. This is precisely one of the main challenges of our Mediterranean cities.

. The second parameter (CORRECTED COMPACTNESS) is closely linked to the previous one. While COMPACTNESS measures the relationship between buildings and the territory they occupy, in the same building this indicator relates to the amount of staying space found in their immediate environment. Therefore, the built volume in a neighbourhood (m3) is measured in connection with its staying space (m2 of the staying space obtained before).

So in the first case very high values ​​or zero are often reached since the denominator tends to 0 as seen above. On the other hand, in the neighbourhoods of our cities’ extensions you can also reach those values ​​yet it is not usual; at the time operations to improve public space (increase in pedestrian space) are made they begin to reach acceptable values. It is recommended values ​​between 10 and 50 meters (m3 building / m2 staying space) in at least half of the territory occupied by our neighbourhood as guarantor of public space vitality. Again the estimate is intended to prevent excesses: is equally damaging both the lack and excess of quality public pedestrian space. Hence, a maximum and minimum value is offered.

. Finally we will discuss a final indicator that blends the two and with which it is intended that the presence of pedestrian quality public space is distributed all around our cities (by means of the streets) and not focus only on parks and squares (which in existing consolidated areas are not very abundant). So this third indicator (STREET PEDESTRIAN SPACE) measures the percentage obtained by comparing the street area for pedestrian use with the total (pedestrian + road traffic). The qualification of which we spoke above means that in a neighbourhood where all the streets have minimum sidewalks and a excessive presence of the car, but it contains a big plaza inside, can obtain acceptable values of Absolute Compactness. Nevertheless, these quality pedestrian spaces are concentrated exclusively in the streets.

As you might imagine at this point, in many streets of our recent developments it is not uncommon to find values ​​close to 15% given the minimum width of sidewalks. Furthermore, although the situation in our old neighbourhoods is better, typically reaching values ​​close to 40% (and therefore providing motor vehicles with 60% of the street space) the trend and aim to achieve is to reverse this value reaching over 60% of the street for pedestrian use.

For more technical information on these indicators you can see pages 465-468 and 501-502 of the Methodological Guidelines for Audit, Certification and Accreditation of Quality and Sustainability in the Urban Environment.