The Spatial and Functional Structure of Urban Logistics

A city has a spatial and functional structure impacting on the organization of activities, transport infrastructures and freight distribution. The spatial structure is reflective of the distribution and the density of urban activities and it is usually divided in areas such as the central business district, the urban core, suburbia and exurbia. The functional structure is composed of the infrastructures, modes and operations supporting urban freight distribution.

Suburbanization has impacted a large share of the global urban landscape and characterizes a specific context in which freight distribution takes place. Although suburbia is functionally integrated to the central city (CBD and urban core), it is also a distinct space with its own consumption patterns. Suburban logistics differs from city logistics over two fundamental issues:

• Spatial structure. The urban spatial structure is commonly multipolar, of lower density, and involves higher consumption patterns (higher income levels). It is also in suburbia where large freight terminals such as ports, airports and intermodal yards tend to be located. This implies that suburbia handles the majority of the interface between the metropolitan area and national as well as global freight distribution systems. At accessible locations (such as an highway interchange) suburban centers with commercial and office activities have emerged. They have become new nexuses of freight distribution, particularly if large scale commercial activities such shopping malls are concerned. Yet, the spatial structure is prone to diseconomies as lower population densities and a more disorganized land use pattern are associated with longer trips.
• Functional structure. Suburbia faces less congestion than the central city, implying that last mile constraints are less acute; parking difficulties are rarer and full truck lengths / loads (e.g. 53 foot trailers in North America) are able to circulate on most of the major roads. Suburbia is thus an environment highly conductive to logistics as it offers accessibility to markets (the urban core as well as neighboring suburban areas), the availability of land as well as lower congestion levels.

Through logistics sprawl, terminal and warehousing activities that conventionally were located close to the city center have been replaced by terminal and modal specific clustering of logistics activities.

• Port-centric and airport centric activities tend to support interactions between global and city logistics. Urban areas highly connected to the global maritime and air transport systems are commonly labeled as gateways.
• Road centric and highway centric activities involve a variety of supply chains and seek accessible locations with affordable land.
• The growth of intermodal rail transportation, particularly in relation with port container traffic, has been prone to the setting of rail centric logistical activities.