Keywords: sustainable development; Urban planning; Rail transit; Construction and operation costs
As a brand-new era in the historical development of civilization, the birth of the city declared a complete change in the way of human existence, and thus created the initial form of urban construction and planning. Today, with the tide of globalization, China is experiencing an unprecedented process of population migration and land urbanization. The practice of urban planning with China characteristics increasingly embodies the advanced concept of future-oriented sustainable development. Traffic is an indispensable aspect of modern urban planning. For China, a country with a large population and rapid development in all aspects, it is of great significance to make a realistic and forward-looking urban transportation plan scientifically.
Based on the great choice faced by urban traffic planning under the background of accelerating urbanization, this paper puts forward its own views and suggestions on how to solve the coordinated development of rail transit and existing urban public transport system, especially how to build and operate urban rail transit economically and optimally.
1 Rail transit is an important choice for urban traffic planning in China.
All the problems faced by urban transportation planning stem from three basic factors: the rapid growth of population, the confusion of urbanization and the motorization of travel modes. To this end, planners must carefully choose among various possible decision-making directions. In 2004, the foreign professional magazine World Urbanization Outlook pointed out that it took only half a century for the world population to grow from about 2.5 billion in 1950 to more than 6 billion in 2000, and it is expected to reach more than 8 billion in another 30 years. As the largest developing country in the world, the social and economic development of China in the past 20 years of reform and opening up has driven10.3 billion rural population to flow into cities, and the mode of transportation of ordinary urban residents has also undergone fundamental changes in these 20 years. The motorization of urban travel mode is accelerating day by day, which has caused the problem of "it is very difficult to go out" which is common in all major cities in China today. Professionals call it serious urban road traffic congestion.
Generally speaking, urban transportation modes can be roughly divided into walking, cycling, motorcycle-assisted vehicles, cars and public transportation. Urban traffic at home and abroad has basically experienced the same development process from walking and cycling to motorcycles and cars. However, when human beings generally entered the automobile age, the United States and Europe chose different modes of transportation and urban forms. In the United States, cars are the main means of transportation, and most cities are scattered and chaotic. The European continent attaches great importance to public transportation, especially rail transit. Large cities connect the city center, suburban living and employment areas and suburban satellite towns through rail transit, forming a polycentric city form [1]. The birth of rail transit system makes it possible for the development of the city to change from centralized to decentralized, and also creates the phenomenon of "separation of occupation and residence" in the city center. It should be acknowledged that private cars and rail transit are two representative modes of transportation in cities in developed countries, which respectively reflect better quality of life and higher traffic efficiency. Before the reform and opening up, the number of these two modes of transportation in big cities in China was almost negligible. In recent years, they have taken the first step from scratch, showing great vitality.
The diversification of urban functions and social activities is the basic feature of big cities, which determines that the traffic demand of big cities is bound to be varied, and the modes of travel that people can choose should also be varied, and all modes of travel can give full play to their greatest advantages within their respective scope of application [2]. The motorization of urban traffic in China is in its infancy, and bicycles and other non-motor vehicles are still the dominant way for most urban residents to travel. With the sustained and rapid growth of social economy and the continuous improvement of people's material and cultural level, establishing a multi-level, three-dimensional and diversified transportation system is the only development direction of the rapidly growing number of big cities in China. Under this goal, scientifically planned rail transit theoretically provides the possibility of meeting the requirements of sustainable development to the maximum extent.
The present situation of urban traffic congestion determines that government departments at all levels should focus on planning urban rail transit public transport system with the advantages of sustainable development of environmental system, resource system and social system in the macro-decision-making process [3]. Recently, there are many publications on this issue in China, so I don't want to repeat them here. From the technical and economic point of view, this paper discusses the practical feasibility of further solving some specific problems faced by rail transit construction and accelerating its development.
2 Rail transit should pay attention to the coordination with the urban public transport system
Generally speaking, the core content of rail transit planning is to fully realize the optimization of line location and transfer facilities, and to maximize the complementary and coordinated operation with the existing public transport system in all aspects.
First of all, urban rail transit is a large-scale systematic project, which involves a wide range and is complex. It needs the cooperation of many disciplines and must be closely combined with the long-term planning of urban construction and development. As an integral part of urban planning, rail transit planning is integrated with the whole urban transportation network planning. In order to avoid sparse passenger flow, the route direction should be as reasonable as possible, otherwise, the small passenger flow and low traffic volume will inevitably lead to rail transit not playing its expected backbone role. In a word, reasonable planning and layout combined with the overall passenger demand of the city is a necessary condition to ensure the dominant position of urban rail transit. Of course, this rational layout should fully consider the overall planning of different urban land use spaces. Beijing subway lines are obviously laid out along urban roads, and the rail transit network is highly consistent with the chessboard pattern of urban roads, which precisely reflects the special requirements for protecting the ancient city of Beijing. A similar example in this respect is Nanjing Metro 1 Line crossing the ancient city in an elevated way from the vicinity of Zhonghua Gate, giving full consideration to the coordination needs of underground stations with surrounding environment, overhead lines and ground landscape.
Secondly, in the comprehensive planning of urban public transportation with rail transit as the leading factor, great attention should be paid to strengthening the construction of transportation transfer hubs, making unified arrangements and orderly adjustments between rail transit and existing conventional public transportation systems, and ensuring the convenient transfer of rail transit such as light rail and subway with urban buses, taxis, ferries and other means of transportation, as well as the smooth connection with airports, railway stations, ports and other transportation places. Faced with the impact of automobile traffic, the big cities in the above-mentioned European developed countries are seeking new traffic development models. A large number of car parking lots will be built in the subway stations along the route leading to the suburbs, so as to guide car passengers to enter the central city after changing, and give full play to the advantages of large capacity of rail transit. The newly-built Shanghai South Railway Station in China has successfully integrated the zero-distance transfer between the railway and two urban rail transit and dozens of bus lines in the planning and design, which has become a sample worth learning.
Finally, we should pay full attention to the interactive relationship between the integration and improvement of rail transit and urban conventional public transport. Rail transit in most countries in the world is gradually developed after the formation of the existing urban public transport system. For a long time to come, bus/tram will still be one of the more widely used means of transportation for people to travel. According to the current economic development level, population size and total traffic demand of many cities in China, the overall position of conventional public transport has not changed much in the short term. However, in the process of gradually developing rail transit, the inefficiency of the traditional public transport system should be completely corrected and improved. In addition to scientific network layout, harbor parking platform, reasonable vehicle operation diagram and service query display information system, the idea of ensuring bus priority in road use from the perspective of planning and legislation needs to be implemented concretely.
In recent years, under the background of supporting the development of rail transit and public transport, how to build a large-capacity bus rapid transit system (BRT) has attracted the attention of professional planners. Bus Rapid Transit System (BRT) is a public transportation mode that uses modern large-capacity special vehicles to travel quickly in special road space. It has the capacity and speed close to rail transit, and the construction and operation costs are relatively low. Moreover, it can be used to upgrade the existing urban bus road system to a great extent, and even be considered as an alternative way of rail transit in some cities with less population.
In 2003, the State Council 8 1 was issued, and many cities in China immediately pushed the development of BRT projects to the forefront of alleviating urban traffic congestion. The newly compiled bus/tram factory network planning of Beijing central city includes 18 BRT lines, with a total length of about 300 kilometers. On the premise of emphasizing the high coordination of mobility and accessibility, BRT is integrated into the overall structure of public transport network for the first time. In addition, the first middle bus lane opened in Kunming during the Expo will soon be upgraded to a standardized modern bus rapid transit system. Hangzhou's medium-and long-term public transport plan based on the urban development model and spatial functional layout has also established the first 28-kilometer BRT connecting east and west, which was basically opened this year. 3 rail transit should solve the problem of low-cost construction and operation
As one of the largest infrastructure projects in the city, urban rail transit has a huge investment. The average comprehensive cost of subway construction in Beijing, Shanghai and Guangzhou in the past few years has exceeded 600 million yuan per kilometer. Obviously, the economic capacity of most cities in China is hard to bear such a high cost. Therefore, it is difficult to realize urban rail transit without solving the cost problem of rail transit. Considering the construction and operation costs of rail transit comprehensively, the author thinks that the following three aspects should be seriously considered to solve the cost problem.
3. 1 The land space for rail transit should reflect the principle of gradual reservation.
In the general construction cost of rail transit, the land occupation cost, including the demolition cost, is an indispensable part, and its social cost nature will not change because of the free allocation model in some countries. In order to reduce this cost, many cities have reserved space for the construction of rail transit lines and stations in the completed bus master plan. However, the specific timing of line construction depends on the different processes of urban development, and the formation of passenger flow in some lines needs a long-term and gradual process.
Therefore, how to adapt to the increasing passenger demand and use the reserved land space reasonably and effectively is a realistic problem that must be carefully planned and considered for the low-cost development of rail transit. In most cities in Brazil, municipal authorities mostly develop BRT in corridors that have not been developed recently by rail transit, and build BRT lanes in the middle of roads, with the original intention of reducing the initial investment and operating costs of rail transit projects [4]. In fact, the first BRT line opened to traffic in Beijing in 2005 was laid on the reserved M8 rail transit corridor, which fully met the recent demand of 8 000 passengers per hour in one direction.
The economic and rational utilization of land space not only needs to be established as the guiding principle of rail transit development in urban planning, but also should be implemented on the design drawings of each sub-project of rail transit system engineering. According to Shanghai Urban Master Plan 1999-2020, about 800 kilometers of rail transit lines will be built by 2020. If all continue to adopt the current centralized power supply mode, the subsystem needs to build more than 50 main substations.
For the time being, regardless of the huge investment of hundreds of millions of yuan in a main substation, it will be amazing to occupy and consume land resources only by building substations and cable channels. In view of this, the relevant departments in Shanghai recently organized experts to demonstrate the optimization scheme, reducing the original planned 5 1 main substation of the whole network 18 line to 39 by 2020, saving investment of more than 654,380+0 billion yuan.
3.2 The construction mode of rail transit should embody the principle of economy and rationality.
The history of urban rail transit in the world for nearly a hundred years presents a variety of development modes, which provide us with a variety of choice modes, such as subway light rail, guide rail, tram, suburban railway, magnetic levitation and so on. Linear motor traction system is considered as the most promising traction system. In cities with a population of over one million in China, we have some successful experiences in developing rail transit at low cost by adapting to local conditions and using existing conditions. Three-quarters of the length of the first phase of Shanghai Pearl Light Rail is the reconstruction and utilization of the original railway inner ring line, which is a useful inspiration and demonstration for other cities such as Wuhan, where the existing railway lines are abandoned or the utilization rate is low. In addition, Shenyang, Changchun, Harbin and other northeastern cities still have some tram lines [5]. On this basis, unified planning and development of modern rail transit should also achieve the purpose of saving some costs.
In fact, one of the reasons for the high cost of urban rail transit construction in China is that it is divorced from the national conditions and unilaterally pursues luxury grades. In planning and design, it is a large number of similar public transport systems with high network density, small station spacing and low load intensity. It should be noted that rail transit is essentially a means of transporting a large number of medium and long-distance passengers quickly, relying on other means of transportation to transport customers, thus achieving large capacity and high load. Because the mode of low network density and large station distance can obviously improve the running speed and shorten the travel time, it can not only reduce the project cost, but also reduce the running cost. Because of this, planning the BRT system as an extension of both ends of the rail transit line, or choosing the mixed network mode of "rail transit +BRT", will help to achieve the low-cost goal of appropriately reducing the laying density of the rail network.
In addition, the high operating cost of domestic rail transit is partly related to the traditional thinking mode and fragmented management mode left over from the planned economy. Until today, when many cities apply for rail transit projects, each line is planned to have an independent depot, control center and main substation. This small and comprehensive space and management system will inevitably lead to a great waste of resources. In Japan, where rail transit is very developed, Imperial Capital High-speed Transportation Group operates eight lines with a total length of 183.2 km, but only 1 integrated control center is set in the 16 station system. On the other hand, in China, even in the Shanghai subway system with high resource level, there are still eight control centers that have been built or will be built, plus 1 Rail Transit Operation Coordination and Emergency Center.
3.3 The supporting management of rail transit should reflect the principle of adapting to local conditions.
As mentioned above, the planning of urban rail transit should not blindly pursue high standards. Those who build the ground and overhead will never go underground, and those who build the light rail will never build the subway, because the cost of the latter is often more than three times that of the former. In addition, in the civil engineering that has a great influence on the cost of subway construction, the buried depth of underground station and the height of station building are two key factors that determine the cost. Therefore, the significance of reasonably designing the depth of foundation pit and the height of station building to reduce the total cost cannot be underestimated in any case.
If the choice of rail transit mode and construction standard has a greater impact on the cost of civil engineering, rail workers. The other half of the total cost (45% ~ 50%) depends on the construction, purchase and installation costs of technical equipment and other hardware. Take subway vehicles as an example. At present, the domestic price is only 1/2 ~ 1/4 of that of imported products. Therefore, one of the keys to reduce the cost is to improve the localization level of vehicles, traction, power supply and signals that constitute the main part of technical equipment. In this regard, the Nanjing subway, which was later completed and put into use, provided us with a very convincing example. According to relevant magazine reports, the contract negotiation of vehicle projects and the careful adjustment of localization scheme have greatly reduced the imported parts and materials and reduced the international transportation cost of imported equipment. With the successful localization rate of 70 countries, the contract price of vehicle projects has been reduced from about $6.5438+0.35 million to $6.5438+0.10.65 million, saving more than 40 million RMB than the design estimate.
Of course, rail transit generally belongs to the field of public goods, and the simple ticket income is far from enough to pay the daily operating expenses after opening. Medium and long-term fiscal balance is a challenge that all countries in the world need to work hard to meet. According to the author's understanding, in the total revenue of Hong Kong subway, ticketing revenue accounts for about 60%, the remaining 40 9 and 6, and advertising and property management each account for half [6]. This successful comprehensive development and management mode of subway and property in Hong Kong has been introduced into the management of Beijing Metro Line 4 through the establishment of a Sino-Hong Kong joint venture company at the beginning of this year, and all parties expect it to show encouraging prospects for the construction and operation of domestic rail transit.
refer to
Zou Shengyong, 1. Optimization of overall urban traffic structure for sustainable development [J]. Journal of Traffic System Engineering and Information Technology, 2006,6 (2):108.
2 David Bayless .. the present situation of urban traffic accessibility in the world [J].TRI Magazine (Traffic Edition), 2006 (2): 17- 18.
3 Fan Wei Ying. Thoughts on the Sustainable Development of Urban Transportation [J]. Transportation, 2006 (2): 67.
4 Quan and Sun Zhuangzhi. Rational Thinking on Bus Rapid Transit and Rail Transit [J]. Journal of Transportation System Engineering and Information Technology, 2006,6 (2):117.
5 Sun Zhang. Century Review of Urban Rail Transit [J]. Shanghai Transportation, 2006 (3): 14.
6 Lu Peiyan, Zhou Liyan .. Sustainable urban traffic: ideas, policies and methods [J].Asce, 2006 (6): 76-77.