TULIP / ADHOC architects. Image © Raphael Thibodeau

替换沥青路面可以建立一个更加可持续和开放的城市
Replacing Asphalt Can Build a More Sustainable and Open City

由专筑网邢子，小R编译

联合国人居署制定的城市繁荣指数（CPI）是根据生产力、基础设施发展、环境可持续性、生活质量和公平/社会包容五个参数来评估城市的繁荣程度。这五个因素或多或少地体现在世界每个城市的街道模式中。街道具有多种功能，如人员和货物的流动，能源、水和信息的供应，废物的收集处理，树木、植物、昆虫或鸟类的生长，阴影和太阳辐射，可供休憩的长椅，与邻居敬礼和交谈的地方，操场或去面包店的小路。在这个意义上，街道是公共的、有活力的空间，它可以发挥多种功能，并提供不同活动的场所。

城市中分配给街道的土地从曼哈顿的密集网格（36%）到大多数郊区的小巷系统（不到10%）不等。大多数繁荣城市的街道用地比例很高，如华盛顿特区（25%）、巴塞罗那（33%）或多伦多（29%）。因此，城市核心区能够改善充满活力的城市生活。

通常，当我们想到街道时，只会注意到汽车的移动或停放。不幸的是，街道大多是为车辆而设计。尽管如此，越来越多的因素正在改变传统的街道模式。城市核心区公共交通的改善，汽车共享、滑板车或电动自行车等新的出行选择，以及环境法规对交通的限制，都改变了我们对私家车作为基本出行方式的看法。事实上，在大多数大城市的核心区，人们从拥有汽车的居民逐渐过渡到租用交通设施的居民。这种情况迫使开发商重新考虑在新建筑中设置地下停车场的必要性，或者至少减少目前每户的停车位标准。

The City Prosperity Index, CPI, set by UN-Habitat, evaluates urban prosperity according to five parameters as productivity, infrastructure development, environmental sustainability, quality of life, and equity/social inclusion. To a greater or lesser extent, these five factors are represented in the street pattern of every city in the world. Streets have multiple functions as the mobility of people and goods, the supply of energy, water, and information, the collection of waste, the growth of trees, plants, insects or birds, the shadow and sun radiation, the bench where to sit, the place to salute and talk with your neighbors, a playground, or the access to the bakery where you buy the bread. In this sense, streets are public and vibrant spaces, which can perform multiple functions and activities.
The land allocated to streets in cities ranges from the dense grid of Manhattan (36 percent) to the cul-the-sac system of most sub-urban areas (less than 10 percent). Most of prosper cities have a high percentage of land allocated to the street, as Washington D.C (25 percent), Barcelona (33 percent), or Toronto (29 percent). Accordingly, cities core has the opportunity to perform and enhance a vibrant urban life.
Often, when we think about streets, we only see cars moving or parked. Unfortunately, streets have been mostly designed for vehicles. Notwithstanding the above, there is an increasingly growing of factors, which are changing the traditional street pattern. The improvement of public transport in cities core, the new options of mobility as car sharing, scooters or electric bikes, and the restrictions of mobility due to environmental regulations have changed our perception of private cars as an essential good. In fact, in most of the big city’s core, there is a gradual transition from residents who own a car, to residents who rent a car. This situation is already forcing developers to reconsider the need for underground parking in new constructions, or at least to reduce the current standards of parking places per home.


Sant Antoni Superblock / Leku Studio. Image © Del Rio Bani

如果这是未来的趋势，那么我们能从车辆较少的街道中获得什么呢？要回答这个问题，首先，我们需要了解街道的基础设施如何运作。大多数的街道都是过度确定的，这意味着，大多数活动都是事先设计好的，几乎没有意料之外的行动空间。因此，人行道标志着街道的功能划分。有大量的沥青路面用于移动和停放车辆，瓷砖用于人行道，还有少量的土壤用于种植树木。在一些历史中心，如圣地亚哥-德孔波斯特拉，这种功能划分并不存在。所有的功能只有一个界面，行人和车辆共同生活，没有冲突。

较少的车辆和较低的速度可能代表了功能重叠的一个可能，城市核心区的限速为20公里/小时，而伦敦市中心一英里范围内的平均车速为8公里/小时，人类的平均步行速度为5公里/小时，因此，汽车、自行车和行人的平均速度相近。较慢的车辆和分配给车辆的较少面积可能会出现意想不到的可能性。基本上，我们可以增加用于植被的土壤面积和用于进行非正式活动的铺装面积。铺装区的这种转换可以提供一个城市环境的自然化过程，以及一个更有活力和惊喜的城市生活。

If this is the future trend, what can we expect from streets with fewer vehicles? To answer this question, first, we need to understand how the infrastructure of a street works. Most of streets are overdetermined. This means that most activities are previously designed, with little room for unexpected actions. Thus, the pavement marks the division of function in streets. There is a lot of asphalt for moving and parking vehicles, tiles for sidewalks, and a small amount of soil for trees. In some historical centers, as Santiago de Compostela, this functional division does not exist. There is only one paver for all functions, where pedestrians and vehicles live together with no conflicts.
Less vehicles with lower speed may represent a big opportunity for overlapping functions. The speed limit in the city’s core is 20 km/h, while the average vehicle speed within one mile of the city center in London is 8 km/h, and the average walking human speed is 5 km/ h. Thereby, cars, bikes, and pedestrians are moving at a similar average speed. Slower vehicles and less area allocated for vehicles may arise unexpected possibilities. Basically, we can increase the soil area for vegetation and the paver area for the performance of informal activities. This switch in the pavement area can provide a process of naturalization of the urban environment, together with a more vibrant and unexpected urban life.  


Pedestrian streets in Santiago de Compostela, Spain. Image © Jose Arcos Aguilar | Shutterstock

如前所述，街道是可以支持不同行动和活动的基础设施。一旦分配给车辆的土地减少，街道就有机会让自然回归。它们提供能源、水和信息，并且从此刻开始，它们可以改善自然生态系统的发展，这样就有机会用鸟儿的歌唱取代内燃机的噪音。此外，自然生态系统不仅仅是植树造林，它是关于建立一个由多种生物体相互作用形成的复杂和动态的生态系统，人类是其中的一小部分。传统的城市维护是过度的清洁，其根源是工业革命期间出现的城市疾病和大流行病。如今，不再有好坏的植物，如杂草和观赏草种之间的区别了，所有的生物体都可以在自然生态系统中发挥相关作用。

As said before, streets are infrastructures that can support different actions and activities. Once that the land allocated for vehicles is reduced, streets have the chance to bring nature back. They supply energy, water, and information, and from now on, they can enhance the development of natural ecosystems. We have the opportunity to replace the noise of internal combustion with the singing of a bird. Moreover, natural ecosystems are not just about planting trees. It is about building a complex and dynamic ecosystem formed by the interaction of multiple living organisms, in which humans are a small part of it. The traditional maintenance of cities, based on aggravated cleanliness, has its origins in the urban diseases and pandemics, that arise during the Industrial Revolution. Nowadays, there is not anymore, the distinction between good and bad plants, as weeds and grass. All living organisms can have a relevant role inside natural ecosystems. 


Revitalization of the Albarrada de Mompox / OPUS. Image © Sergio Gómez

土壤和铺装可以在被车辆占据的传统道路上出现，前者可以用于城市的自然化，后者可以提供非正式活动的空间，成功之处在于土壤和摊铺机的重叠代替了沥青路面。土壤和铺装可以共享类似的活动。此外，街道上的车辆减少，无论是永久的还是临时的，一条街道可以用作几个小时的欢乐跑，也可以是一整个周末的休闲市场。以这样的方式，增加分配给自然和临时活动的街道面积，建立一个更加可持续和开放的城市。

让自然做出它的选择，我们必须提供一些措施。

The soil and the paver can colonize the traditional surface occupied by vehicles. While the first one can be used for the naturalization of the city, the second can enhance informal activities. But the success lays in the overlapping of the soil and the paver, and the removal of the asphalt. The soil and the paver can share similar actions and activities. In addition, vehicles either can be removed from streets, permanently or temporarily. The closing of a street can range from a couple of hours for a fun run, to a whole weekend for a market. Thus, the increase of the street’s surface allocated for naturalization and for the performance of temporary and informal activities can build a more sustainable and open city.
Let nature do its job. We just must help a little.