公交导向型城市开发机理及模式构建

城市交通、土地利用和城市空间结构的相互关系一直是城市地理学、城市规划学和交通地理学研究的核心问题。大容量公共交通、混合型土地开发、宜人的步行环境和高质量的公交服务是公交导向型开发(TOD)模式的主要特点。本文分析了TOD对城市土地利用和城市空间结构的作用机理发现:土地开发强度、土地利用结构以及土地价值是TOD影响城市土地利用的3 个主要方面,而TOD对路网结构、城市规模和城市空间布局的作用进一步影响城市空间结构及其演化。进一步研究发现:大容量公共交通的建设使得城市竞租曲线和开发密度具有多波峰的特点,遵循"随着时间的变化从城市中心向外围递减"的规律。基于中外城市发展背景差异,本文从宏观、中观和微观3 个层面提出建立以大容量公共交通为主轴、以TOD站点为枢纽的轴辐网络状城市空间结构,并提出了TOD站点开发的距离、级差密度、多样性和设计的4Ds原则。

Development mechanism and model construction of TOD for Chinese cities

The relationships among urban transportation, land use and urban spatial structure are always the key topics in the studies of urban geography, urban planning and urban transportation. With the emergence of the issues such as urban sprawl, low efficiency of land use and traffic jam, it has become more and more important to study how to coordinate land use and urban transport in the planning of city development. As we all know, public transportation is not only one of the elements of urban lives, but also a driving force of urban spatial devolvement. TOD (Transit Oriented Development) is an urban development model under the guidance of New Urbanism, which emphasize the innovation of transport technology and the recognition of humans themselves. TOD integrates a mass transit system into the urban spatial structure, i.e., residential areas and commercial areas, at the macro-level, and neighborhoods develop around the transit stations or stops at the micro-level. TOD encourages high density development in an appropriate scale, mixed land use, comfortable environment for pedestrians and a good public transit system, to harmonize land use and transport, and finally enables the urban spatial structure to develop compactly and orderly. This paper analyzes TOD's mechanism on urban land use and urban spatial structure, and has found that TOD plays an important role in urban land use by influencing land use density, land use structure, and land value. Meanwhile, TOD influences the urban spatial structure by unique road structures, urban scale and urban spatial distribution. Further study indicates that the construction of mass transit makes the curves of urban rental and land development density show "multi-peaks" characteristics, following the principle of "decreasing from the city center with the increase of travel time". Although there are differences between China and other countries in urban population density, mixed land use, land property and public transport service, this paper attempts to build a suitable TOD model for the cities in China. The TOD model is built in three parts (steps): gross urban development, urban spatial structure and design of TOD unit, which results in a hub-and-spoke urban structure, with mass transit routes as corridors and the TOD node as a hub. Based on the types of public transportations, a TOD can be classified as a BRT-oriented TOD or a Rail-oriented TOD. Each city can choose the type suitable to its urban population, GDP, financial capacity and traffics along the transit lines. Design of TOD units should consider land use principles including distance, density, diversity and design, and adopts a special land use strategy. Finally, this paper puts forward a series of measures, policies and suggestions to ensure a successful TOD implementation, with time and location as two major impacting factors. Generally speaking, when a city is developing and expanding its urban areas rapidly, construction of mass transit will greatly influence its spatial distribution; conversely, when a city is developing slowly or has already reached its mature period, the effect of mass transit on land use is relatively small. In a word, TOD emphasizes the integration of local efficiency and overall efficiency and is a suitable model for urban development in China.