Urban, city, or town planning is the discipline of land use planning which explores several aspects of the built and social environments of municipalities and communities. Other professions deal in more detail with a smaller scale of development, namely architecture, landscape architecture and urban design. Regional planning deals with a still larger environment, at a less detailed level.
Another key role of urban planning is urban renewal, and re-generation of inner cities by adapting urban planning methods to existing cities suffering from long-term infrastructural decay.[1]
Contents [hide]
1 History of Planning
2 The Sustainable City
3 Aspects of Planning
3.1 Aesthetics
3.2 Safety
3.3 Slums
3.4 Reconstruction and Renewal
3.5 Transport
3.6 Suburbanization
3.7 Natural environment
4 Actors in the planning process
5 Books Seminal to Urban Planning
6 References
7 Further reading
8 See also
9 External links
[edit] History of Planning
Urban planning as an organised profession has existed for less than a century, however most settlements and cities have displayed various degrees of forethought and conscious design in their layout and functioning.
As agriculture replaced a nomadic existence, permanent human settlements, and larger settlements began to appear. These early cities became centres for trade, defence, and politics and as centres for distributing the agricultural surplus a settled farming society produces.
Cities laid out with forethought and design permeate antiquity. Perhaps the earliest of these were those of the ancient Mesopotamian and Harrapan civilizations of the third century BCE.
Ur located near the Euphrates and Tigris rivers in modern day Iraq and some ancient cities of the Indus Valley in modern day India are perhaps the earliest examples of deliberately planned and managed cities in history. The streets of these early cities were often paved and laid out at right angles in a grid pattern. There was also with a hierarchy of streets (commercial boulevards to small residential alleyways). In Harrapan settlements, archaeological evidence suggests the houses were laid out to protect from noise, odours, and thieves, and had their own wells, and sanitation. Ancient cities often had drainage, large granaries, and well-developed urban sanitation[2]
The Greek Hippodamus (c. 408 BC) is widely considered the father of city planning in the West, for his design of Miletus; Alexander commissioned him to lay out Alexandria, the grandest example of idealized urban planning of the Mediterranean world, where regularity was aided in large part by its level site near a mouth of the Nile.
The ancient Romans used a consolidated scheme for city planning, developed for military defence and civil convenience. The basic plan is a central plaza with city services, surrounded by a compact rectilinear grid of streets and wrapped in a wall for defence. To reduce travel times, two diagonal streets cross the square grid corner-to-corner, passing through the central square. A river usually flows through the city, to provide water and transport, and carry away sewage, even in sieges.[citation needed] Effectively, many European towns still preserve the essence of these schemes, as in Turin.
The idea of rational planning collapsed with the idea of the res publica in the European Early Middle Ages. Round a fortress or fortified abbey or next to a Roman nucleus — sometimes itself abandoned— urban growth occurred "like the annular rings of a tree"[3] whether in an extended village or the center of a larger city. Since the new center was often on high, defensible ground, the city plan took on an organic character, following the irregularities of elevation contours like the shapes that result from agricultural terracing.
The ideal centrally-planned urban space: Sposalizio by Raphael, 1504The ideal city resurfaced in the Early Renaissance in Florence, where the star-shaped city plan was adapted from the new cannon-resistant star fort. The star-shaped fortification had a formative influence on the patterning of Renaissance urban planning: "The Renaissance was hypnotized by one city type which for a century and a half— from Filarete to Scamozzi— was impressed upon utopian schemes: this is the star-shaped city"[4] Radial streets extend outward from a defined center of military, communal or spiritual power. Only in ideal cities did a centrally-planned structure stand at the heart, as in Raphael's Sposalizio of 1504 (illustration); as built, the unique example of a rationally-planned quattrocento new city center, that of Vigevano, 1493-95, resembles a closed space instead, surrounded by arcading. Filarete's ideal city, building on hints in Leone Battista Alberti's De re aedificatoria, was named "Sforzinda" in compliment to his patron; its twelve-pointed shape, circumscribable by a "perfect" Pythagorean figure, the circle, takes no heed of its undulating terrain in Filarete's manuscript.[5]
The true heirs of Greek rational planning were the Muslims, who are thought to have originated the idea of formal zoning (see haram and hima and the more general notion of khalifa, or "stewardship" from which they arise),[citation needed] although modern usage in the West largely dates from the ideas of the Congrès Internationaux d'Architecture Moderne.
Many cities in Central American civilizations also engineered urban planning in their cities including sewage systems and running water. Mexico-Tenochtitlan, was the capital of the Aztec empire, built on an island in Lake Texcoco in what is now the Federal District in central Mexico. At its height, Tenochtitlan was one of the largest cities in the world, with close to 250,000 inhabitants.[citation needed]
During the last two centuries in the Western world (Western Europe, North America, Japan and Australasia) planning and architecture can be said to have gone through various stages of general consensus. Firstly there was the industrialised city of the 19th century, where control of building was largely held by businesses and the wealthy elite. Around the turn of the 20th century there began to be a movement for providing people, and factory workers in particular, with healthier environments. The concept of garden cities arose and some model towns were built, such as Letchworth and Welwyn Garden City the world's first garden cities, in Hertfordshire, UK. However, these were principally small scale in size, typically dealing with only a few thousand residents.[6]
It wasn't until the 1920s when modernism began to surface. A modernist city was to be a sort of efficient, workable utopia. There were plans for large scale rebuilding of cities, such as Paris in France, though nothing major happened until the devastation caused by the Second World War. After this, some modernist buildings and communities were built. However they were cheaply constructed and became notorious for their social problems.[7]
Modernism can be said to have ended in the 1970s when the construction of the cheap, uniform tower blocks ended in many countries, such as Britain and France. Since then many have been demolished and in their way more conventional housing has been built. Rather than making everything uniform and perfect, planning now concentrates on individualism and diversity in society and the economy. This is the post-modernist era.[8]
[edit] The Sustainable City
Sustainable development has become some sort of a 'buzz-word' in the planning industry, with the recognition that present ways of consumption and living have led to problems like the overuse of natural resources, ecosystem destruction, pollution, growing inequality in cities, the degradation of human living conditions and human-induced climate change. Planners have, as a result, taken to advocating for the development of sustainable cities.[9]
However, the notion of sustainable development can be considered as rather recent and evolving, with many questions surrounding this concept.[10] That said, it is often not difficult to recognise what are 'unsustainable' forms of lifestyles, and urban planning is recognised to play a crucial position in the development of sustainable cities.
Stephen Wheeler, in his 1998 article, suggests a definition for sustainable urban development to be as "development that improves the long-term social and ecological health of cities and towns."[11]He goes on to suggest a framework that might help all to better understand what a 'sustainable' city might look like. These include compact, efficient land use; less automobile use yet with better access; efficient resource use, less pollution and waste; the restoration of natural systems; good housing and living environments; a healthy social ecology; sustainable economics; community participation and involvement; and preservation of local culture and wisdom.[12]
The difficult challenge facing planners comes with the implementation of sustainability visions, policy and programmes, and in the midst of doing so, the need to modify institutions to achieve these goals. This is still being worked out by urban planners.
[edit] Aspects of Planning
[edit] Aesthetics
This article does not cite any references or sources.
Please help improve this article by adding citations to reliable sources. (help, get involved!)
Any material not supported by sources may be challenged and removed at any time.
This article has been tagged since June 2006.
Towns and cities have been planned with aesthetics in mind, here in Bath (England), 18th century private sector development was designed to appear attractive.In developed countries there has been a backlash against excessive man-made clutter in the environment, such as signposts, signs, and hoardings.[13] Other issues that generate strong debate amongst urban designers are tensions between peripheral growth, increased housing density and planned new settlements. There are also unending debates about the benefits of mixing tenures and land uses, versus the benefits of distinguishing geographic zones where different uses predominate.[14]
Successful urban planning considers character, of "home" and "sense of place", local identity, respect for natural, artistic and historic heritage, an understanding of the "urban grain" or "townscape," pedestrians and other modes of traffic, utilities and natural hazards, such as flood zones.
Some argue that the medieval piazza and arcade are the most widely appreciated elements of successful urban design, as demonstrated by the Italian cities of Siena and Bologna[citation needed].
While it is rare that cities are planned from scratch, planners are important in managing the growth of cities, applying tools like zoning to manage the uses of land, and growth management to manage the pace of development. When examined historically, many of the cities now thought to be most beautiful are the result of dense, long lasting systems of prohibitions and guidance about building sizes, uses and features. These allowed substantial freedoms, yet enforce styles, safety, and often materials in practical ways. Many conventional planning techniques are being repackaged using the contemporary term, smart growth.
There are some cities that have been planned from conception, and while the results often don't turn out quite as planned, evidence of the initial plan often remains. (See List of planned cities)
[edit] Safety
The medieval walled city of Carcassonne in France is built upon high ground to provide maximum protection from attackers.Historically within the Middle East, Europe and the rest of the Old World settlements were located on higher ground (for defense) and close to fresh water sources[citation needed]. Cities have often grown onto coastal and flood plains at risk of floods and storm surges. Urban planners must consider these threats. If the dangers can be localised then the affected regions can be made into parkland or Greenbelt, often with the added benefit of open space provision.
Extreme weather, flood, or other emergencies can often be greatly mitigated with secure emergency evacuation routes and emergency operations centres. These are relatively inexpensive and unintrusive, and many consider them a reasonable precaution for any urban space. Many cities will also have planned, built safety features, such as levees, retaining walls, and shelters.
In recent years, practitioners have also been expected to maximize the accessibility of an area to people with different abilities, practicing the notion of "inclusive design," to anticipate criminal behaviour and consequently to "design-out crime" and to consider "traffic calming" or "pedestrianisation" as ways of making urban life more pleasant.
City planning tries to control criminality with structures designed from theories such as socio-architecture or environmental determinism. These theories say that an urban environment can influence individuals' obedience to social rules. The theories often say that psychological pressure develops in more densely developed, unadorned areas. This stress causes some crimes and some use of illegal drugs. The antidote is usually more individual space and better, more beautiful design in place of functionalism.
Oscar Newman’s defensible space theory cites the modernist housing projects of the 1960s as an example of environmental determinism, where large blocks of flats are surrounded by shared and disassociated public areas, which are hard for residents to identify with. As those on lower incomes cannot hire others to maintain public space such as security guards or grounds keepers, and because no individual feels personally responsible, there was a general deterioration of public space leading to a sense of alienation and social disorder Source
Jane Jacobs is another notable environmental determinist and is associated with the "eyes on the street" concept. By improving ‘natural surveillance’ of shared land and facilities of nearby residents by literally increasing the number of people who can see it, and increasing the familiarity of residents, as a collective, residents can more easily detect undesirable or criminal behaviour.
The "broken-windows" theory argues that small indicators of neglect, such as broken windows and unkempt lawns, promote a feeling that an area is in a state of decay. Anticipating decay, people likewise fail to maintain their own properties. The theory suggests that abandonment causes crime, rather than crime causing abandonment[citation needed].
Some planning methods might help an elite group to control ordinary citizens. Haussmann's renovation of Paris created a system of wide boulevards which prevented the construction of barricades in the streets and eased the movement of military troops. In Rome (Italy), the Fascists in the 1930s created ex novo many new suburbs in order to concentrate criminals and poorer classes away from the elegant town. Robert Moses' developments in New York were intended to limit the effectiveness of public transit; bridges over parkways were built too low to accommodate buses, in order to restrict access to the beach by racial minorities and the poor.
Other social theories point out that in Britain and most countries since the 18th century, the transformation of societies from rural agriculture to industry caused a difficult adaptation to urban living. These theories emphasize that many planning policies ignore personal tensions, forcing individuals to live in a condition of perpetual extraneity to their cities. Many people therefore lack the comfort of feeling "at home" when at home. Often these theorists seek a reconsideration of commonly used "standards" that rationalize the outcomes of a free (relatively unregulated) market.
[edit] Slums
Main article: Slums
The rapid urbanization of the last century has resulted in a signifcant amount of slum habitation in the major cities of the world, particularly in the Third World. There is significant demand for planning resources and strategies to address the issues that arise from slum development, and many planning theorists and practitioners are calling for increased attention and resources in this area, particularly the Commonwealth Association of Planners.[15]
The issue of slum habitation has often been resolved via a simple policy of clearance, however more creative solutions are beginning to emerge such as Nairobi's "Camp of Fire" program, where established slum-dwellers have promised to build proper houses, schools, and community centers without any government money, in return for land they have been illegally squatting on for 30 years. The "Camp of Fire" program is one of many similar projects initiated by Slum Dwellers International, which has programs in Africa, Asia, and South America.[16]
[edit] Reconstruction and Renewal
Main article: Urban Renewal
The overall area plan for the reconstruction of Kabul's Old City area, the proposed Kabul - City of Light Development.Areas devastated by war or invasion represent a unique challenge to urban planners: the area of development is not one for simple modification, nor is it a "blank slate". Buildings, roads, services and basic infrastructure like power, water and sewerage are often severely compromised and need to be evaluated to determine what, if anything, can be salvaged for re-incorporation. There is also the problem of population; more often than not, people are also still living in these areas, displaced but not removed, and their issues need to be addressed. Historic areas and religious or social centers also need to be preserved and re-integrated into the new city plan. A prime example of this is the capital city of Kabul, Afghanistan, which after decades of civil war and occupation has regions that have literally been reduced to rubble. Despite this, the indigenous population continues to live in the area, constructing makeshift homes and shops out of whatever can be salvaged. Any reconstruction plan proposed, such as Hisham Ashkouri's City of Light Development, needs to be sensitive to the needs of this community and its existing culture, businesses and needs.
Urban Reconstruction Development plans must also work with government agencies as well as private interests to develop workable designs.
[edit] Transport
Main article: Transportation Planning
Very densely built-up areas require high capacity urban transit, urban planners must consider these factors in long term plans.
Although an important factor, there is a complex relationship between urban densities and car use.There is a direct, well-researched connection between the density of an urban environment, and the need to travel within it[citation needed]. Good quality transport is often followed by development. Development beyond a certain density can quickly overcrowd transport[citation needed].
Good planning attempts to place higher densities of jobs or residents near high-volume transportation. For example, some cities permit commerce and multi-story apartment buildings only within one block of train stations and four-lane boulevards, and accept single-family dwellings and parks further away[citation needed].
Densities can be measured in several ways[citation needed]. A common method, used is the Floor area ratio, using the floor area of buildings divided by the land area. Ratios below 1.5 could be considered low density, and plot ratios above five very high density. Most exurbs are below two, while most city centres are well above five. Walk-up apartments with basement garages can easily achieve a density of three. Skyscrapers easily achieve densities of thirty or more.
City authorities may try to encourage lower densities to reduce infrastructure costs, though some observers note that low densities may not accommodate enough population to provi
1 突破居住区规划的小区单一模式
[期刊论文] 《城市规划》 ISTIC PKU CSSCI - 2001年2期- 邓卫
现代居住区规划的审美价值取向--以德克萨斯州林地社区规划为例
2[期刊论文] 《规划师》 ISTIC PKU - 2006年2期- 裘鸿菲 , 陈益峰 , Qiu Hongfei , Chen Yifeng
3 对《城市居住区规划设计规范》若干问题的思考
[期刊论文] 《规划师》 ISTIC PKU - 2005年8期- 李旭光 , LI Xuguang
4源于自然融于环境营造特色--杭州"都市水乡"居住区规划设计构思
[期刊论文] 《规划师》 ISTIC PKU - 2003年11期- 顾浩
5 论居住区规划的概念设计
[期刊论文] 《建筑科学》 ISTIC PKU - 2009年4期- 刘艳梅
6 《城市居住区规划设计规范>的适用范围
[期刊论文] 《城市规划》 ISTIC PKU CSSCI - 2002年10期- 中国城市规划设计研究院 , 居住区规划设计研究中心
7 浅析城市居住区规划
[期刊论文] 《安徽建筑》- 2008年4期- 葛岚 , Ge Lan
8 浅议我国居住区规划与住宅设计
[期刊论文] 《长江大学学报（社会科学版）》- 2008年6期- 王小俊
9从城市社区的组织管理新模式谈居住区规划结构--以杭州市为例
[期刊论文] 《规划师》 ISTIC PKU - 2003年7期- 王剑云 , 应四爱 , 文旭涛
10城市居住区规划中的抗震防灾问题研究
[期刊论文] 《建筑学报》 ISTIC PKU - 2009年1期- 卜雪旸 , 曾坚 , Pu Xueyang , Zeng Jian
由于不知道你需要的是哪方面的规划，先找这些，大家都是要写论文的人，希望可以帮到你。
[1] 左金风. 改革开放30年来城市规划法治的发展评述[J]. 求实. 2009(S2)
[2] 鲁长亮,王翠萍. 五个统筹与城市规划关系研究[J]. 荆楚理工学院学报. 2009(10) [3] 徐善登. 公民参与与城市规划公共性的实现[J]. 广西社会科学. 2009(09)
[4] 张同升,刘长岐. 快速城镇化发展背景下的中国城镇规划问题[J]. 城市发展研究. 2009(08) [5] 胡礼梅,王培茗. 当前省域城镇体系规划研究——以云南省为例[J]. 云南地理环境研究. 2008(05)
[1] 李建平. 加快新罗区城镇化进程的思考[J]. 闽西职业技术学院学报. 2006(02)
[2] 张同升,刘长岐. 快速城镇化发展背景下的中国城镇规划问题[J]. 城市发展研究. 2009(08) [3] 席雪红. 河南省城镇化进程中亟待解决的问题[J]. 郑州航空工业管理学院学报(社会科学版). 2005(06)
[4] 王铁城. 住宅城郊化与城镇化建设关系的探析[J]. 黑龙江科技信息. 2010(07) [5] 国务院发展研究中心课题组. 我国城镇化建设存在的问题及原因[J]. 红旗文稿. 2007(19)
[6] 张雅琼,程胜. 浅析河南省的城镇化建设[J]. 科教文汇(上旬刊). 2009(11) [7] 刘涛,赵志亮. 河南省城镇化与工业化发展关系的实证分析[J]. 中国城市经济. 2011(06)
[8] 韦璐. 浅析我国城镇化发展的主要模式及存在问题[J]. 魅力中国. 2009(21) [9] 王卓敏. 我国欠发达地区城镇化发展中存在的问题及原因分析——以河南省为例[J]. 特区经济. 2010(07)
[10] 王建国,张辉. 改革开放以来河南省城镇化发展进程及对策建议[J]. 郑州轻工业学院学报(社会科学版). 2009(05)
1. <迈向新世纪的流动人口管理研究> 【出 版 社】 华东师范大学出版社 【书 号】9787561723876
【所属分类】 社会科学 > 社会学 > 人口学
2.《城镇流动人口管理模式研究》浙江大学学报（理学版） / 浙江省科委《流动人口对城镇发展的影响研究》课题
3.《中国计划生育学杂志》2008年12期 ——目录 国家人口计生委召开党组扩大会议传达贯彻国务院会议精神 全面开展“关怀关爱行动” 提高流动人口计划生育服务管理水平 辽宁省扎实开展计划生育科技大练兵活动
4.《城市外来流动人口管理运行机制探略》郭开怡 《中国市场》 2007年第1期
5.<流动人口的六项权利和六项义务>———《中国人口报》2006-9
6.《人口与计划生育》杂志 ——《人口与计划生育》杂志是国家人口和计划生育委员会主管的惟一的指导全国人口计划生育工作的综合性理论刊物。
7《计生协会参与流动人口服务管理的实践与思考》——《人口与计划生育》杂志 2009年第3期
8.〈浅析人口流动与计划生育〉 文章来源： 来源:新学术论坛第12期供稿文/常岚[导读
期刊门户-中国期刊网 2009-2-24
注：中国国内高校中（最权威-内容最具体-实例最丰富）的人口管理和计划生育类期刊资料-《南京人口管理干部学院学报》，里面有很多期的内容都是关于人口及人口管理的。
摘要：人类社会发展正面临着人口膨胀、资源超前消耗、环境急剧恶化的空前挑战，可持续发展理念指导下的的现代城市规划，决定了我国的大部分地区只能追求以公共交通为基础的高质量的可达性。具有多项显著优点的轨道交通(尤其是地铁运输模式)，是解决大城市中心区域交通拥堵问题的最佳途径，但必须在依托改善既有公交系统、并通过优化网络便捷换乘而达到相互协调配合的前提下，注意降低它的建造运营成本。
关键词：可持续发展；城市规划；轨道交通；建造运营成本
作为文明历史发展中的崭新时代，城市的诞生宣告了人类生存方式的彻底变革，也由此开创了城市建设与规划的初始形态。今天，伴随全球化的大潮，中国正经历着前所未有人口迁移与国土城市化过程，充满中国特色的城市规划实践，越来越体现出面向未来可持续发展的先进理念。交通是现代城市规划中一个不可或缺的方面，对于中国这样一个各方面处于跳跃式发展的人口大国，科学地制定切合实际又具有前瞻性的城市交通规划，意义尤其重大深远。
本文以当前城市化加速背景下城市交通规划面临的重大选择作为切入点，对如何解决轨道交通与现存城市公交系统的协调发展，特别是如何经济、优化地建造与运营城市轨道交通，提出自己的看法与建议。
1 轨道交通是我国城市交通规划的重大选择
城市交通规划面临的一切问题起源于三个基本因素：人口剧增、城市化加谜与出行方式机动化。为此，规划者们必须在各种可能的决策方向之问慎重取舍。国外专业杂志《世界城市化展望》2004年载文指出，全世界人口从1950的25亿左右增长到2000年60多亿，只用了半个世纪的时间，预计再过30年将达到80亿以上。作为世界最大的发展中国家，中国改革开放二十多年来的社会经济发展带动了1亿3千万农村人口流入城市，一般城市居民的交通出行方式也在过去二十多年里发生了根本性的变化。城市出行方式机动化日益加速，造成了今日中国主要大中城市里司空见惯的“出门难行路难”问题。专业人士称之为严重的城市道路交通拥挤。
一般而言，城市交通方式大致可分为步行、自行车、摩托助动车、小汽车与公共交通国内外的城市交通基本上都经历过从步行、自行车到摩托、小汽车大体相同的发展过程。但是，当人类普遍进入小汽车时代后，美国和欧洲选择了不同的交通方式和城市形态。美国以小汽车为主要交通工具，城市多数呈现分散、蔓延的形态。欧洲大陆则十分重视公交、特别是轨道交通，大城市通过轨道交通将市中心、近郊生活就业区与远郊卫星城镇连结起来，形成多中心的城市形态[1]。轨道交通系统的诞生，使城市的发展从中心聚集型向离心分散型转变成为可能，也因此造就了城市中心的“职住分离”现象。应该承认，私人小汽车和轨道交通是目前发达国家城市中具有代表性的两种交通方式，分别突出地体现着更优的生活质量与更高的运输效率。改革开放前，这两种交通方式在我国大城市中的数量少到几乎可以忽视不计的程度，近年来，它们已分别迈出了从无到有的第一步，表现_出强大的生命力。
城市的功能和社会活动的多样化是大城市的基本特征，由此决定了大城市的交通需求必然是多种多样的，人们可选择的出行方式也应该是多种多样的，并且所有的出行方式都可以在各自适用的范围内发挥出最大优势口[2]。我国的城市交通机动化正处于起步状态，自行车等非机动车仍是目前大部分城市中居民出行的主导方式。随着社会经济持续、快速增长与人民物质文化水平不断提高，建立多层次、立体型多元化的交通体系，是我国数量迅速增长的大城市的唯一发展方向。在此目标之下，科学规划的轨道交通理论上提供了最大限度满足可持续发展要求的可能性。
城市交通拥挤现状，决定了各级政府部门在宏观决策过程中，理当重点考虑规划在环境系统、资源系统、社会系统等多方面具有可持续发展优势的城市轨道交通公共交通系统[3]，这方面国内刊物近来论著颇多，本文不欲在此重复赘述。以下谨从技术与经济的角度，探讨进一步解决轨道交通建设面临的一些具体问题，加速走向它的现实可行性。
2 轨道交通需重视与城市公交系统的和谐
一般而言，轨道交通规划工作的核心内容是要充分实现路线选址与转乘配套两者的最优化，与现有的公交系统在各个环节上达到最大限度的互相补充协调运作。
首先，城市轨道交通是一项涉及面广泛复杂、需要许多专业协调配合的大型系统工程，必须与城市建设发展中长期规划密切结合起来进行。作为城市规划的有机构成部分，轨道交通的规划与整个城市交通的线网规划实为一体。为了避免客流稀少，线路走向应尽可能合理，否则，小客流低运量必然导致轨道交通无法发挥预期的骨干作用。总之，结合城市的总体客运需求合理规划布局，是保证城市轨道交通主导地位的必要条件。当然，这种合理布局要充分考虑不同城市的用地空间总体规划。北京地铁线明显采用了沿城市道路走向布局的方式，轨道交通网络形态与市区道路棋盘式格局高度一致，恰恰体现了保护北京古城的特殊要求。这方面类似的例子，还有南京地铁1号线采用高架方式从中华门附近跨越古城，也充分考虑了地下车站与周围环境、高架线路与地面景观的协调需要。
其次，在以轨道交通为主导编制城市公交综合规划时，要十分注意加强交通换乘枢纽的建设，将轨道交通与现有的常规公交体系统一安排、有序调整，保证轻轨、地铁等轨道交通与城市公共汽车、出租车、轮渡等多种交通工具的方便转接，以及与机场、火车站、港口等其他运输场所的顺利衔接。前文所举的欧洲发达国家的大城市，面对小汽车交通的冲击，纷纷寻求一种新的交通发展模式，在通向郊区的沿线地铁站大量修建小汽车停车场，引导小汽车乘客换乘后进入中心城区，使轨道交通的大运量优势得以发挥。国内方面新近建成的上海火车南站，则成功地将铁路与两条城市轨道交通与几十路近、远郊公交汽车线的零距离换乘需要融入规划设计中，成为一个值得学习借鉴的样本。
最后，我们不能不充分注意轨道交通与整合改善城市常规公交之间的互动关系。世界上绝大多数国家的轨道交通都是在既有城市公交体系形成后逐渐发展起来的。在未来相当长一段时间内，公共汽车／电车仍将是人们出行使用较广泛的交通工具之一。根据我国许多城市目前的经济发展水平与人口规模及交通总量需求，常规公交的整体地位短期内变化不大。但是，常规公交系统效率低下的现状应该在逐步发展轨道交通的过程中加以综合整治与改善。除了科学制订线网布局，修建港湾式停靠站台，合理编制车辆运行图，建设服务查询显示信息系统等具体措施外，从规划立法角度保障公交的道路优先使用权的思路也有待于细化落实。
近来，在轨道与公交配套发展背景如何建设大容量快速公交系统(BRT)引起了专业规划人员的高度关注。BRT是一种利用现代化大容量专用车辆、在专用道路空间快速行驶的一种公交方式。它具有接近轨道交通的运力与快捷，建造和运营成本又相对低廉，而且很大程度上可以利用改造提升现有的城市公交道路系统，在某些人口规模不是很大的城市中甚至可以考虑作为轨道交通的替代方式。
2003年国务院81号文件出台后，国内许多城市马上把发展BRT项目推到了缓解城市交通拥堵的前台。北京市新近编制的中心城区公共汽／电车厂线网规划中包含了18条BRT线路，总长约300多km，在强调机动性与可达性高度协调的前提下，首次将BRT作为一个功能层次融人公交线网整体结构中。此外，昆明市在园艺世博会期间开通的国内首条位于道路中央的公交专用道，即将升级为规范的现代BRT系统。杭州根据城市发展模式与空间功能布局制订的中远期公交规划，也确立以轨道与BRT为骨干，东西走向穿城而过的首条28 km BRT今年已基本开通。 3 轨道交通应解决低成本建造运营问题
作为城市中最大的基础建设项目之一的城市轨道交通投资巨大，京、沪、穗前几年修建地铁的综合造价平均每千米超过了6亿元人民币。显然，大多数国内城市的经济能力很难承受起如此高昂的成本。因此，不解决轨道交通的造价问题，城市轨道交通难以实现。综合考虑轨道交通的建造与运营费用，笔者以为解决成本问题拟应围绕以下三个方面认真思考。
3．1 轨道交通的用地空间应体现预留渐进原则
一般轨道交通建设成本中，包括拆迁费用在内的占用土地成本是其中不可忽视的一个组成部分，并不因为某些国家无偿划拨方式而改变它的社会成本性质。为了降低这方面的成本，许多城市在已经完成的公交总体规划中，都为轨道交通的线路场站建设预留了用地空间。然而，线路建设的具体时机取决于城市发展的不同进程，某些线路的客流形成需要一个长期渐进的过程。
因此，如何既能适应逐渐增长的客流需要，又能合理有效地利用预留土地空间，是低成本发展轨道交通中必须慎重规划考虑的现实问题。在巴西的大多数城市里，市政当局大都在轨道交通近期没有开发的走廊上发展前文介绍的快速公交，将BRT专用道建在道路中央，初衷就是为了降低轨道交通项目的初期投资与运营费用[4]。实际上，北京2005年全线通车的第一条BRT线路，正是敷设在预留的M8轨交走廊上，完全满足了近期单向8 000人次／h的客流需求。
经济合理地使用土地空间，不仅需要作为城市规划中发展轨道交通的指导原则加以确立，更应当具体落实在轨道交通系统工程的每一个子项目的设计图纸上。根据《上海市城市总体规划1999—2020》，到2020年将建成800 km左右轨道交通线，如果全都继续采取目前的集中供电模式，届时仅该项子系统就需建造50多座主变电所。
暂且不论一座主变电所动辙上亿元的巨额投资，仅建造变电所及电缆通道所需占用消耗的土地资源就将十分惊人。有鉴于此，最近上海相关部门已组织专家进行优化方案论证，将2020年前全网18条线路原先计划建造的51座主变电所减少为39座，更可节约投资10亿元人民币以上。
3．2 轨道交通的建造模式要体现经济合理原则
世界城市轨道交通近百年的历史展现了丰富多彩的发展模式，为我们提供了地铁轻轨、导轨、有轨电车、郊区铁路、磁悬浮等多种选择模式，线型电机牵引系统则被公认为最有发展前途的一种在我国百万以上人口的城市中，因地制宜地利用现有条件低成本发展轨道交通，已有了一些成功的经验。上海的明珠轻轨一期有3／4长度是改造利用原先的铁路内环线，这对武汉等其他一些存在废弃或利用率很低的铁路既有线路城市，不啻是一种有益的启发与示范。另外，东北沈阳、长春、哈尔滨等城市，还存有部分有轨电车线路[5]，在此基础上统一规划发展现代轨道交通，应该也能够达到节省一部分费用成本的目的。
其实，国内城市轨道交通建设成本居高不下的原因之一，还在于脱离国情片面追求豪华档次。表现在规划设计上就是大量采用类似于公共汽车系统的高线网密度、小站间距、低负荷强度。需知，轨道交通本质上属于快速大量运送中长距离乘客的交通工具，依靠其他交通工具为它输送客源，达到大运量高负荷。由于低线网密度、大站间距模式能够明显提高运行速度、缩短旅行时间，所以不但可以降低工程造价，而且还可以降低运行成本。正因为如此，将BRT系统规划为轨道交通线路两端的延伸段，或选择“轨交+BRT”的混合网络模式，都有助于达到适当降低轨道线网敷设密度的低成本目标。
另外，国内轨道交通运营成本高的部分原因，还与计划经济遗留下的传统思维方式与条块分割的管理模式密切相关。直到今天，许多城市在申请轨道交通立项时，每条线路都规划有独立使用的车辆段、控制中心、主要变电站，这套小而全的空间与管理体系必然造成资源的极大浪费。在轨道交通十分发达的日本，帝都高速交通营团运营管辖着8条线路总长183．2 km，但是所属16个车站统共只设置了1座综合控制中心。反观国内，即使在资源共享程度较高的上海地铁系统，已建和待建的控制中心仍有8座，另加1座轨道交通运营协调及应急中心。
3．3 轨道交通的管理配套要体现因地制宜原则
如前所述，城市轨道交通的规划不应盲目追求高标准，该建地面、高架的绝不钻入地下、该建轻轨的绝不建地铁，因为后者的造价往往是前者的3倍以上。此外，对地铁建设成本影响甚大的土建工程中，其地下车站底板的埋置深度与车站建筑高度是决定造价大小的两个关键因素。因此，合理设计基坑深度与车站建筑高度对降低总成本的意义，无论如何也不应低估。
如果说轨交模式、建造标准的选择较多地影响到土建工程造价部分，轨道工。程总造价的另外一半(45%～50 %)则取决于技术装备等硬件的建设、购置、安装费用。以地铁车辆为例，目前国产价格仅为进口产品的1／2～1／4。因此，降低成本费用的关键之一，是提高构成技术装备主要部分的车辆、牵引、供电、信号的国产化水平。这方面，较晚竣工投入使用的南京地铁为我们提供了很有说服力的例证。据有关杂志介绍，该项目通过车辆项目的合同谈判与国产化方案的慎密调整，大大减少了进口部件和材料，降低了进口设备的国际运输成本，在成功实现70 国产化率的情况下，车辆项目合同价从最初的每辆约135万美元降低到116．5万美元，与设计概算相比节约投资4 000多万人民币。
当然，轨道交通总体上属于公共产品领域，单纯的票务收入远远不足以偿付开通后的日常性运营支出，中长期的财务收支平衡对世界各国都是一个需要艰难应对的挑战。笔者了解到的香港地铁总收入中，票务收入约占60 ，其余40 9，6中广告与物业管理各占一半[6]，这一香港较为成功的地铁和物业综合发展经营模式，今年初已通过成立中港合营公司引入北京地铁4号线的管理，各方都期待着它能为国内轨道交通建设运营展示一种令人鼓舞的前景。
参考文献
1 邹胜勇．面向可持续发展的城市总体交通结构优化[J]．交通运输系统工程与信息，2006，6(2)：108．
2 David BAYLISS．世界范围的城市交通可达性现状(英文)[J]．TRI杂志(交通版)，2006(2)：17—18．
3 樊颖玮．城市交通可持续发展问题的思考[J]．交通与运输，2006(2)：67．
4 全永棠，孙壮志．关于BRT与轨道交通的理性思考[J]．交通运输系统工程与信息，2006，6(2)：117．
5 孙章．城市轨道交通的世纪回眸[J]．上海交通运输，2006(3)：14．
6 P．Y．Loo，L．Y．Chow．可持续城市交通：理念，政策与方法(英文)[J]．ASCE，2006(6)：76—77
