The Athens Charter proposes four basic activities of the city - living, working, recreation and transportation. The figure shows the basic relationship between the four basic urban activities and the urban land use structure and the urban transportation system. Four basic activities of city live, work and recreational activities are to be carried out in a fixed place has a fixed target, the arrangement of land use is the absolute land use, and embodies the reciprocal relationship between them is the relative land use between each other, from the position and quantity relationship of urban land layout structure, reflects the static function relations of the city.

Buchanan's vision of a comprehensive urban design, led by transport, repurposed part of London into a vast mega-structure that vividly illustrates the "new urban form" that motor vehicles demand. Among other things, this envisages the city's urban highways and multi-storey car parks, towers and pedestrian platforms set up in the maze system of distributor roads and underground services. It was noted that this approach was "almost revolutionary", but in fact the design was later highlighted as "the revolutionary, even disastrous, impact of modern transport planning on the form of towns".

Today, both transport and urban design have a high profile, and their conjunction increasingly appears crucial to contemporary planning. This thesis sets out to explore how transport provision can be used towards urban structuring and hence the design of urban areas. In doing so, it cannot avoid the legacy of Traffic in Towns, nor the intervening reactions against its revolutionary impact.

It turns out that urban design methods dominated by highway design are "disastrous". In urban areas, the actual consequences of highway projects are not limited to the destruction of existing urban structures, such as invasion, separation, demolition and wither, which can be collectively referred to as urban destruction. They also include the negative effects of highway engineering as a formative urban layout. In fact, this means that the methods of highway design tend to lead to monotonous or dysfunctional layouts, resulting in a lack of identity, vitality or urbanity in new development. Although the cost of urban destruction is tangible, it is also an opportunity to create more ideas in the design and create a good urban environment.

The loss engendered by this creation would be all the more tangibly felt here, due to being directly juxtaposed with an existing, functional city quarter. A bustling commercial street, would be transformed into a multilane motorway, terraced and flanked on either side by parallel collector-distributor roads, forming a traffic canyon some 100m wide, apparently accommodating a dozen lanes of traffic. Its four level intersection  would occupy an area that could accommodate a hospital or university.

Such retrofits are hardly considered today. Even by the early 1960s, the wisdom of integrated redevelopment, traffic-led urban design and top-down planning was questioned, which Jane Jacobs linked to the failure of urban planning. Christopher Alexander then similarly questioned the strict simplicity of a hierarchical urban system.

In Buchanan's case study of design, the overlap between the street energy that Jacobs pursued and the urban life that Alexander pursued would disappear. Tottenham Court Road's role as a ‘’ seam’ between the cities of Fitzrovia in the west and Bloomsbury in the east will be lost as these areas will be separated and isolated. Shops will be stuck on the deck of the sidewalk, far from passing trade. Buses will be packed in the middle of the regional distributor level. The familiar urban "pattern" of a grocery store next to a bus stop and a bar on the corner will disappear.

Today, of course, the rhetoric of the 'motor age' has been replaced by the rhetoric of sustainability and New Urbanism. Sustainable transport modes and neo-traditional street patterns are in vogue. The 'monolithic modernism' of highway engineering and car-oriented urban 'solutions' are on the back foot.

However, Buchanan's basic blueprint is: the core principles of layout and the "hierarchy" of roads, and positive relational functions, urban morphology and structure, living in current theory and practice. His design idea is not only to coordinate the urban traffic, but also to put forward the basic blueprint of the urban structure based on the traffic system, showing the possibility of "traffic architecture". In a big sense, we still build towns like this.

The UK's housing development in 1999 exceeded expectations and its expanding needs urgently needed to reconcile the aspirations of contemporary urbanism with the functional structure of transport supply. This poses a challenge for all designers: it's not just about where to build new housing, it's about all the design forms associated with it.

Yet, despite present good intentions to prioritize sustainability, and the desire (at least among urbanists) for a return to more traditional urban forms, achieving these is not straightforward. While the destruction of central London might no longer be contemplated, it would be difficult to actually create a Fitzrovia or a Tottenham Court Road today. We could not create the exemplary urbanity of traditional cities such as London.

This, then, represents the stimulus and the challenge set for the research. Accordingly, this thesis will examine relationships between transport and urban structure, and hence explore how transport can contribute positively to the structuring of urban areas in a way appropriate to today's needs. This means reconciling the functional needs of traffic with those of sustainable transport modes and with wider urban design objectives. In doing so, the thesis must go beyond the rhetoric of contemporary urbanism, to the root of the urban structural problem, and develop an approach which can  addressing today's ends.

1.1Objectives

The particular concern of the thesis is the contribution of transport provision to urban structure, and hence the physical layout of urban areas. This focus on the structure of cities, and the transport structure at that, may be regarded as the definitive scope of the thesis. The research can ultimately contribute to the better design of cities, although the approach of this thesis represents just one possible way of doing so. Within the chosen scope, however, a substantial exploratw5KWuwTVtYE9tZRBQqsTFw==ion is possible, and a clear sequence of objectives and sub-objectives may be identified.

These themes are the urban design centered on the urban structure proposed by the Shanghai cooperation organization, and the physical layout provided by transportation.

Therefore, our purpose is: how to design the urban structure, especially the layout of residential area in the transportation network paper?

How should transport How does transport relate networks be structured to urban structure?

What are the desired By what means should properties of network transport-constituted urban structure? structure be designed?

How to describe network How to explain existing urban structure?

How do recognizable How has desirable urban network forms relate to structure traditionally been urban functions?

In chapter 1, our goal is divided into two concerns: the relationship between traffic and urban structures, and the structure of transportation networks. The traffic network structure further solves the expected attributes of the urban structure and the methods to realize these attributes by design. These, in turn, raise several more specific questions about describing and interpreting network structures. Although these more detailed questions do not need to be explicitly raised at the beginning of the investigation, they will be effectively presented during the study, and they play an important role in linking the arguments and influencing the arguments.

In fact, our research can be viewed in two distinct but intertwined ways. The first part is the "design debate" which has to do with contemporary concerns such as how to integrate transport supplies and urban design, what urban structures are desirable, and how to design them. The second part is an in-depth investigation of "the nature of the urban structure", what it is, how it is described and analyzed, and how it explains the observed structure.

In a sense, urban structural design is included in the overall debate on urban design. The urban structure is a relatively abstract and theoretical part, while the design debate is more directly related to the contemporary design environment. The debate of design idea gives the purpose and relevance of urban structure survey, while urban structure provides some "solutions" for urban design and provides information basis for the debate of design idea.

The research topic is described and discussed from the whole urban design, which is integrated into the whole design concept structure. The chapters are interrelated, rather than an independent discrete theme.

1.2 Scope

In the introduction part of the paper, a series of extensive problems are proposed, and the background is set for the research topic, from which a more detailed set of goals is determined. This section provides an overview of the scope of a range of related theories and more precisely frames the subject areas covered in this article.

1.2.1 General

The urban design debate is an integral part of the norm, and the urban structure idea it proposes should first be considered as a desirable position. The position of this paper is based on the expectations and goals of contemporary theory and practice. These aspirations are seen as embodying the broader social, cultural and economic contemporary wisdom of urban life and are seen as sustainable. Therefore, this paper does not recommend what is a good or bad urban structure, but aims to help better understand the urban structure, thus providing a design method that can be customized for various potential desirable urban structure results.

We focus on the design concept. From the research limitation of the design principle and method, the specific design idea or design specification without the solution is revised. Therefore, by adjusting the research basis, this paper makes corresponding Suggestions for the subsequent theoretical research methods and existing design management, thus proving its practicability in principle.

1.2.2 Scope of Urban Structure

Urban structure refers to the physical and spatial structure of urban and regional architecture. In essence, the urban structure is regarded as the continuous structure of urban road and flat space as the medium of public accessibility. This is reflected in various aspects in the structure of public space, street pattern and the ultimate traffic network. In the discussion, we will further emphasize the differences between different transport network structures and mobile space. Urban structures are seen as distinct from urban forms and urban structures, which are thought to deal more with three-dimensional forms and their surfaces.

In this paper, we do not pay attention to the conceptual interpretation of urban structure, such as social structure, economic structure, administrative or institutional structure, will not be included in the scope of this study. Of course, this is not to say that these structures are important or to deny their possible relationship to physical structures. However, conceptualized urban structure may be conceptually excluded from the physical aspect of the structure, which is the subject of this study, which we have clearly defined.

1.2.3 Scope and interplay of policy spheres

The goals of urban planning and design will include a desire for sustainable cities, urban quality and vitality. The broad goals of transport planning will include integrated transport, which aims to improve efficiency and sustainable mobility. To some extent, there is consensus and reinforcement. Sustainable mobility and sustainable urbanization can support each other. But there are also conflicts in some areas, which are defensive responses to the main goal of one design field in another.

There is great concern among urban designers, traffic designers and environmental engineers about the negative impact of trafficr9j7P3pq7OVEqEK7BztD3Q== and infrastructure on urban areas. Because it affects the quality and vitality of the city. The urban designer's expectation of physical design in urban planning makes certain road patterns and pedestrian priority get attention, hoping that it will not affect traffic efficiency and traffic safety.

Overall, our research focuses on the interaction between transport supply and urban design, rather than a single issue entirely within these two areas. Therefore, within this framework, there will be two specific areas of focus. First, it will focus on the role of transport forms that can help achieve urban goals, including urban quality and vitality as well as sustainability. Second, it is natural to focus on possible points of contention when considering the interaction between the "main approach" and the "response". These arguments are effectively reflected in the response.

First, there seems to be a consensus among disciplines that the destruction of cities must be avoided. Traffic planners and engineers today take the environmental impacts seriously and effectively view them as part of their concern that in the past, the urban consequences of road construction and other infrastructure interventions could be considered irrelevant or incidental.

Secondly, to some extent, extensive work has been done in this area, such as the entire field of environmental impact assessment. Similarly, the desire to maintain safety and efficiency is a frequent concern of transportation planners and engineers.

Urban planning designers in the design of the transportation infrastructure and urban route network structure and network design, have found that the creation of the design concept will help urban layout and optimization of settlements, but in terms of transportation function, giti on liquidity, in particular, the lack of promoting the quality of fine designer or urban planner.

It is not usually the responsibility of the traffic designer and the traffic engineer to effectively solve a series of problems in urban life, which is actually a whole problem in urban planning.

This has perhaps only managed to get underway since the mid 1 990s, whi+psxU1+7NlyxEqYaVFwyfQ==ch explicitly links the design of built form with road layout considerations. Even so, to date, efforts seem to have not got far beyond recognition of the oblem2. This is therefore very much a contemporary and pressing issue, and one requiring attention.

1.2.4 Research Scope

Based on the current policies and practices of the UK as the research background and as a whole of urban design, this study was conducted in different countries and locations of different cities, including analysis of some cases from all over the world. Most of the design analysis, design principles and practical results of the study can be applied to different design concepts, not limited to the UK. This study starts from the traditional idea, the mixed use of modern road and comprehensive traffic, as well as the design layout of the traffic and pedestrian priority in residential areas, as a general discussion, thus promoting the innovative development concept, and does not make the design scope specific in the UK.

1.2.5 Scales of Consideration

The research mainly focuses on the scale of "urban blocks or blocks", which is the typical scale of urban design considerations, between the scale of individual buildings that architects usually consider and the scale of complete settlements or traffic networks that strategic planners or traffic planners consider.

Form of the city, or part of the city, is considered to be more important than the overall shape and form a complete city or town, because in most cases, the urban construction gradually upward or outward, rather than the usual in creating a plan and execution behavior. Basically, the scale of the structure in design is the most effective analysis, because of the structure and design process are intertwined. This usually means the size of the design block and quarter.

1.2.6 Focus on Roads and Streets

While the study is nominally about the supply of urban traffic, it will focus primarily on the street network, which combines the road network and the extended pedestrian network. These are major concerns bVWOnwb54BR4ohXy13VhiRA==ecause they directly constitute the public domain and are the main backdrop for most urban design.

Other networks, such as railways and waterways, are less important. While railways have a practical impact on urban structures (and can lead to urban destruction), they are generally not in the public domain. Although waterways have an important influence on the formation of urban structures, the influence of traffic arteries is only a part, and the product of urban design is even less. In other words, these networks are less important to our current research.

Railways and highways, too, are irrelevant to the topic, since their networks are often rough, meaning they tend to be only linear interventions at the local scale of urban design. Configuration, non-linear characteristics are reflected in local scale, such as route bifurcation, or the radial and orbital route between exchanges, which tend to be associated with larger demand patterns, such as the relationship between addressing the overall distribution of urban functions, or geographic settlements, rather than any generalisable configuration pattern. In contrast, there are enough generic roads and various types of streets, such as long, short, motorized and pedestrian streets, to justify their research, as they can be combined into different types of networks in multiple ways.

However, general "transport regulations", rather than "road regulations", are fully retained, since the inclusion of railways and certain other means can be implicitly considered within the scope of this paper.

1.2.7 Key Elements of Transport Modes

This study considers a variety of transportation modes and how these modes can adapt to the distinctive sustainable development concept of urban areas in terms of functional design.

In urban environments, every mode of transport takes up an "evolutionary factor". The public transport system, for example, thrives in densely congested corridors, where competition is fierce in areas where traffic is not heavy. The penetration of the bus in the suburbs is more flexible, although it may have only minimal use in areas with the lowest population density. However, the car is well suited for the dispersed suburbs, and from a Evolutionary factor perspective, the car has also helped drive suburban development. Pedestrians are restricted to a certain extent and disadvantaged by long-distance traffic in the suburbs, but we can find a development market that no other model can match. Finally, we see how some models are " extinct" .The combine the disadvantages of low speed and fixed routes. It now exists only as a museum.

In some cases, new modes of transport have evolved to adapt to new urban conditions.

Bus Rapid Transit is a new public passenger transport system between Rapid Rail Transit and Normal Bus Transit. It is a unique urban passenger transport system that utilizes modern bus technology to cooperate with intelligent traffic and operation management (integrated dispatch system), opens up bus special roads and builds new bus stations, realizes the operation service of rail transit mode and achieves the service level of light rail.

These latter cases represent solutions dealing with the 'mobility-led' problem of serving urban areas with transport. However, the problem can also be approached from the other side: the design of the built environment. Physical planning (embodying urban design and transport provision) can change the 'ecosystem' of the different modes, as it were, to favor one type over another, whether by helping to 'feed' public transport, or by differentially favoring routes for non-motorized modes, or, at least, by ensuring that there are plenty of convenient niches where walking and cycling can naturally flourish. It is this angle - the design of transport networks, in relation to urban structure, rather than direct treatment of systems of transport modes - that is the concern of this thesis.

Urban Traffic comes from urban land and comes back to urban land. The operation of social life and production activities between urban land use, as well as the connection between living, working and leisure activities have generated traffic activities, which requires a city transportation system to shoulder this task. The urban traffic system includes the urban road system, the Urban Transport system and the traffic management system, in which the transport system is the traffic operation network, the road and other facilities are the traffic access network, and the management system is the guarantee of the normal traffic operation. The urban traffic system depends on the dynamic relationship between urban land use, which reflects the dynamic functional relationship of the city. Transportation plays a core role in the four basic urban activities. Urban planning is not only a reasonable arrangement of urban living, work and open space, but also a guarantee of efficient and convenient transportation system. Urban traffic and road system planning (urban traffic system planning) is a core issue of urban planning.

The interpenetration of high-speed, long-distance and near-distance transportation systems makes the urban transportation system interact with each other, forming a multi-functional and comprehensive transportation system mode, which is also the prevailing mode at present. However, public transport and pedestrian transport do not necessarily provide the advantages of distance and crossing at the same time, so they are often complementary, forming a "replacement" system of cars together.

All levels of urban roads are the framework of the organization of the city, but also urban traffic channels, according to the layout of urban land and traffic intensity to arrange the layout of urban road network at all levels. The relationship between the nature and function of various roads (networks) in cities and the layout structure of urban land is shown as the functional layout of urban roads.

The rapid road network mainly serves medium and long distance traffic between urban groups and traffic services connecting expressways. It is advisable to arrange it in the separated green space between urban groups to ensure its speed and smooth traffic. The expressway is basically built into a city cluster, so its spacing depends on the size of the urban cluster in the urban layout structure.

The urban trunk road network is the road network throughout the city, mainly for the urban groups and the main traffic flow within the groups to the medium and long distance traffic services. In order to meet the needs of modern urban traffic motorization development, the urban traffic trunk road network should be laid out in the city, as the main channel of urban traffic and the main normal speed road connected with the express road. Urban traffic trunk roads are roughly grouped into one urban area, while other urban main roads (including living trunk roads and distributed backbone roads) are roughly grouped into one residential area.

The urban road network is a network within the urban cluster, which, together with the urban master road network, constitutes the basic framework of the city and the basic form of the urban road network, mainly serving the medium and short distance transport within the cluster. The road in the city is roughly the size of a residential community.

The city branch road is the road designated in the urban lot according to the traffic demand generated by the detailed arrangement of land use, which should be arranged in the detailed planning, and may form a net in the local section of the city (such as the commercial district, the residential area arranged by the neighborhood), but cannot form a net in the city group and the entire urban area. Therefore, it is not possible to plan in the general regulation of the city, nor to calculate its density and quantity. In the detailed planning, the spacing of city branch roads mainly depends on the division of land.

Basically, the more focused the schema, the less flexibility. Meanwhile, the less power assist, the more limited range. As a result, scope and penetration are considered key attributes that affect traffic flexibility. Therefore, any attempt to optimize the structure of a city for a particular model will be directly related to the scope and flexibility of the model under consideration, among other considerations.

These points may be illustrated by means of a three-way 'monogram', where the car, the pedestrian and public transport represent three distinct extreme (Figure 1.2).

Each model is drawn to an ideal degree of individualism and mechanization. Note that the green model favors this ideal model. The size of the drawing does not represent flexibility. In reality, each collective pattern will occupy a scope, not a point.

The study will also focus on the three "" key" "modes of transport - pedestrians, public transport and private cars - that are considered cruciVV6Kx0fU9v9413laigyG4Q==al in providing routes and their relationship to the urban form.

Other modes effectively fall within these extreme. For example, the bicycle is 'individualistic' like the car or the pedestrian; like the pedestrian it is non-motorized and limited in range to some extent - though not quite as limited or 'slow' as the pedestrian, especially in urban areas, where it may be the fastest mode door-to-door. In some cases the cyclists' needs will be met by the vehicular traffic network (albeit, preferably with the vehicular traffic removed, in other cases their needs will more closely match those of the pedestrian. Where separate treatment would in practice be singled out (e.g., bicycle lanes or bicycle tracks) these would not appear to have much additional influence on urban structure. This is not simply in terms of relatively small proportions (in many western cities) of modes such as bicycles and motorbikes, but in their limited historical role in giving rise to distinctive types of urban form and structure, compared with, say, the classic cases of the historic compact city, the radial  city or the dispersed car-oriented city.

For convenience the thesis will tend to refer to the three 'key modes' themselves (rather than the combinations of attributes that they represent). Thus, references to the car will normally imply a variety of types of traffic, including many road freight traffic movements, for point-to-point journeys. On the other hand, some freight movements, such as serial deliveries, may be more aligned with the characteristics of public transport, as far as implications for optimal layouts are concerned. At the level of resolution considered in subsequent chapters, different forms of public transport are generally not differentiated, although clearly there will be a spectrum of types (bus, guided bus, light rail, rail etc) with slightly different requirements.

1.3 Research method

Urban planning research is not conducted as a simple linear process, but involves a variety of surveys, often feedback to each other. We try to explore various ways to study various urban and structural phenomena, as well as their design and analysis, and be open to what they might lead to. Towards the end of the study, a more integrated process emerged, in which various original research directions were eventually linked.

1.3.1 Literature

We start with different urban structures and design concepts to explore the relationship and function between traffic and urban planning.

In between the consideration of design analysis and design recommendation was

the consideration of the more theoretical topics of urban structure and structuring. This

entailed the consideration of a more eclectic and specialized range of subjects, including

the professional and historical context of design, the geography and geometry of networks,

as well as various philosophies of design and growth of form.

The following conclusions can be drawn from the analysis of the Athenian charter:

1) Human activities are the main activities and decisive factors of urban transportation. The demand, willingness and energy of human activities determine the purpose, mode, frequency and distance of travel. The distribution and activity demand of people in urban land determine the flow and distribution of urban traffic. The study and arrangement of urban traffic in urban planning must be based on the activities of people and the distribution of people in urban land.

2) Urban land use is the decisive factor of urban traffic. Urban transportation is generated from urban land use. A certain urban land use layout produces a certain traffic distribution, and a certain traffic distribution must be matched by a certain road and traffic system. The structure and form of urban road network and public transportation network depend on the layout structure and form of urban land, which should be coordinated with the layout form of urban land.

3)To deal with the reasonable urban land layout and road system, to have the thought of the public traffic and function division, according to the land use of traffic of different functional requirements, reasonable arrangement of different types and functions of the road, beside the road of different function arrangement different nature of the construction land, the formation of road traffic system and city land layout reasonable cooperation relationship.

The history of urban development tells us that the unreasonable traffic distribution is caused by the unreasonable land use, the unreasonable urban layout makes the distance between work and residence too far, and the unreasonable traffic distribution is the root cause of road congestion and traffic obstruction. In the process of urban development, people have gradually realized that the city expands outward in a concentric circle around the original single center of the old city, constantly enlarging the travel distance of people and cars, and constantly increasing the traffic burden in the central area of the city. Therefore, the traffic problems generated by the city cannot be solved by road construction and traffic management alone. The organic evacuation theory proposed by reveals an effective way to alleviate urban traffic by changing the urban layout: the layout of cities in clusters and multi-centers can greatly reduce travel distance and cross-district traffic volume, make traffic balanced distribution and fundamentally solve the traffic problem.

So, study the urban traffic problem must first study the city land layout, ideas to solve the problem of urban transportation must first change, from "the" point of view, based on the rational distribution of urban land, through optimizing urban land layout optimization of traffic distribution from traffic sources, the overall should form multi-center layout depended, urban land to comprehensive layout, a group to achieve perfect basic functions; Secondly, we should deal with the relationship between urban land use layout and road system, and optimize urban traffic and road system through the functional layout of urban traffic and road system coordinated with land use layout. To have the thought of the public traffic and functions of thought in accordance with the land use of traffic of different functional requirements, reasonable arrangement of different types and functions of the road, beside the road of different function layout is not back to the nature of the construction land, the formation of road traffic system of urban land consolidation layout reasonable cooperation relationship) and to organize a group of traffic and across groups, sexual life of traffic and transportation, simplify and reduce the rate of traffic after the spear.

For cities of different sizes and different types, the basic relation of traffic distribution should be studied from the perspective of land use layout, different road traffic network types and modes should be selected according to local conditions, and different road density and traffic organization modes should be determined.

1.3.2 Description and Analysis of Structure

The urban road system is always accompanied by the development of regional cities. The development of any city goes through a process

As cities develop into medium-level cities, large cities and megacities, the centralized layout with land use develops into a combined layout, and the form and structure of urban road transportation system should also undergo fundamental changes.

The city formed in the early stage is a small town, which is also the "old city" part of the later developing city. City is affected by the feudal rules and regulations in China, different grade "old city" of the city scale is different, but most of the present centralized layout for 単 center, the field of city roads are mostly whole squares, despite of the primary and secondary points (still can be divided into one, branch and street level), but significantly narrower width, density is high, more suitable for walking and non-motor vehicle traffic of the seats. The city located in the water network developed area may have the river road fusion, the irregular grid pattern or other forms, the small town located in the traffic important road location may also have the peripheral radial pattern which connects with the urban road network.

The development of a city to a medium-sized city may still be centralized, but there will inevitably be multiple sub-centers. A reasonable urban layout should gradually form a multi-center and relatively compact group layout by strengthening the construction of sub-centers, thus making the urban traffic distribution more reasonable. In the central group, the urban road network still maintains the basic pattern of the old city, while in the peripheral group, the modern three-level road network that is more suitable for motor traffic will be formed, and the grid pattern will still be maintained.

When a city develops into a large city, if it still follows the single-center centralized layout, there will be a series of common problems in big cities, such as too long travel distance, too centralized traffic, traffic congestion and low efficiency of the city. Therefore, the planning must guide the city to gradually form a relatively scattered and multi-center group layout. The central group (which can be composed of the original medium cities) is relatively compact and independent, while several peripheral groups are relatively dispersed. In addition to the third-level road of modern city, the urban express road required for the formation of modern urban traffic between the central group and the peripheral group should be considered, and the urban road system starts to transform into the mixed road network .

The layout of megacities may be "combined city", and the outer city of city will be further developed into several relatively compact peripheral cities based on the original peripheral towns. The central city is developed, adjusted and further combined on the basis of the original big city. Urban road development creates mixed visualizations) there is a need for a reworked POE municipal road network to enhance intercity traffic connections) and a sulfur connectivity arterial road network combined with a rapid road network, which can also be linked between urban areas using highways or expressways.

Generally speaking, the site layout of the old city is relatively compact, and the road network is relatively close and narrow. High density makes traffic more dispersed. Narrow capacity, then can organize one-way traffic, suitable for dispersive traffic mode. In big cities, urban peripheral more put land layout, in order to adapt to the characteristics of long travel distance, requires traffic speed, to organize efficient sets the amount of traffic flow, match with high efficient road traffic facilities, it needs to have a distinct shunt type road network structure, compared to the old city, density is lower, width is ability to adapt to modern traffic will be larger.

The above analysis shows a general rule: different scale and different types of urban land layout have different traffic distribution and traffic requirements, there will be different road network types and modes, and there will be different road network density requirements and traffic organization methods. Therefore, different cities may have different road network types; Different urban areas or sections of the same city may have different road network types due to different land layouts. Different types of urban trunk road network are closely related and closely coordinated with different urban land use patterns.

The research has involved various types of description and analysis of network patterns and structures. This has included general descriptions of network shape, and more detailed geometric and morphological approaches. No single school of thought or analytic method has been adhered to. In fact, the research has precipitated the development of new methods of analysis of network structure, based on consideration of the route as the elemental unit of analysis and design.

This approach combines the strengths of a series of existing approaches, including those based on graphs of nodes and links, spatial configuration, and morphology of plots or buildings.

1.3.3 Use of examples of urban structure

Examples of urban structure have been used to demonstrate different forms of network structure, and in some cases to 'calibrate' certain proposed indicators of structure with recognizable 'types'. This process has aimed for breadth, across a diversity of urban cases, comparing their similarities and differences, rather than tracing the detailed design history or particular design problems of any particular locality. In the pursuit of exploring variation (or similarity) between different urban structural contexts, several examples have been drawn from outside the UK.

The examples of urban structure include not only patterns or designs 'as built' on the ground, but patterns drawn from design guidance or design proposals. Addition, for the purposes of illustration and demonstration, Beijing, Tokyo and some other conceptual cases are cited in this paper.