人口规模与城市轨道交通的治堵效应

利用高德地图发布的道路交通拥堵延时指数大数据,结合断点回归方法,对全国省会城市2015年10月至2018年9月新开通的40多条轨道交通线路进行了分析。结果显示:轨道交通虽能缓解城市道路交通的拥堵状况,但效果并不明显,存在着异质性影响;常住人口在600万至900万人的城市新增轨道交通的治堵效应显著,不足600万人及超过900万人的城市,治堵效应不显著。进一步研究发现,造成治堵效应异质性及总体不显著的原因在于,地方政府兴建轨道交通的决策机制造成了站点布局、通车里程与出行总需求之间的错配。     

A behavioural model of traffic congestion: Endogenizing speed choice, traffic safety and time losses

Conventional economic models of traffic congestion assume that the relation between traffic flow and speed is a technical one. This paper develops a behavioural model of traffic congestion, in which drivers optimize their speeds by trading off time costs, expected accident costs and fuel costs. Since the presence of other drivers affects the latter two cost components and hence the Nash equilibrium speed, a ‘behavioural’ speed-flow relationship results for which external congestion costs include expected accident costs and fuel costs, in addition to the time costs considered in the conventional model. It is demonstrated that the latter in fact even cancel in the calculation of optimal congestion tolls. The overall welfare optimum in our model is found to be off the speed-flow function, and off the average and marginal cost functions derived from it in the conventional approach. This full optimum requires tolls to be either accompanied by speed policies, or to be set as a function of speed. Using an empirically calibrated numerical simulation model, we illustrate these qualitative findings, and attempt to assess their potential empirical relevance.     

A bathtub model of downtown traffic congestion

In standard economic models of traffic congestion, traffic flow does not fall under heavily congested conditions. But this is counter to experience, especially in the downtown areas of major cities during rush hour. This paper analyzes a bathtub model of downtown rush-hour traffic congestion that builds on ideas put forward by William Vickrey. Water flowing into the bathtub corresponds to cars entering the traffic stream, water flowing out of the bathtub to cars exiting from it, and the height of water in the bathtub to traffic density. Velocity is negatively related to density, and outflow is proportional to the product of density and velocity. Above a critical density, outflow falls as density increases (traffic jam situations). When demand is high relative to capacity, applying an optimal time-varying toll generates benefits that may be considerably larger than those obtained from standard models and that exceed the toll revenue collected.     

An integrated model of downtown parking and traffic congestion

This paper is the first to look at cruising for parking from an economic perspective. We present a downtown parking model that integrates traffic congestion and saturated on-street parking; the stock of cars cruising for parking adds to traffic congestion. Two major results emerge from the model, one of which is robust. The robust one is that, whether or not the amount of on-street parking is optimal, it is efficient to raise the on-street parking fee to the point where cruising for parking is eliminated without parking becoming unsaturated. The other is that, if the parking fee is fixed at a sub-optimal level, it is second-best optimal to increase the amount of curbside allocated to parking until cruising for parking is eliminated without parking becoming unsaturated     

An integrated model of downtown parking and traffic congestion

This paper is the first to look at cruising for parking from an economic perspective. We present a downtown parking model that integrates traffic congestion and saturated on-street parking; the stock of cars cruising for parking adds to traffic congestion. Two major results emerge from the model, one of which is robust. The robust one is that, whether or not the amount of on-street parking is optimal, it is efficient to raise the on-street parking fee to the point where cruising for parking is eliminated without parking becoming unsaturated. The other is that, if the parking fee is fixed at a sub-optimal level, it is second-best optimal to increase the amount of curbside allocated to parking until cruising for parking is eliminated without parking becoming unsaturated     

Camaraderie,common pool congestion,and the optimal size of surf gangs

This study integrates some of the seminal public choice research on clubs and recent research on prison gangs into an analysis of the formation of surf gangs. More specifically, this study presents a model examining how surf break congestion, localism effort, and surfing camaraderie work to determine the optimal size of a local surf gang. The benefits of surfing in groups fall under the heading of camaraderie, and their presence means that the optimal surf gang size is bounded away from one. The benefits of camaraderie in surfing will likely be exhausted at small numbers owing to crowding of the surf break.     

襄阳市城区交通拥堵问题分析及对策

随着经济建设的快速发展,城市人口和私家车拥有量急剧增长,造成严重的交通拥堵,同时带来严重的交通安全隐患,城市交通拥堵变成了亟需待解的难题。文章分析了造成襄阳市城区交通拥堵的原因,结合襄阳的城市发展战略和不同地段的拥堵状况,提出采取经济有效的措施,优化城市路网环境,达到交通供求平衡和高效管理。     

A model of population distribution,traffic congestion,and neighborhood crowding in a circular city

An idealized static equilibrium model of a circularly symmetric city is presented. The model allows one to compute the spatial distribution of residences, given certain simple and plausible assumptions about the “costs” of transport, housing and neighborhood crowding. The model is chosen so as to guarantee that in first approximation, the residential population distribution which would be considered optimal by a perfect planner is identical to the distribution reached in a push-shove, laissez-faire equilibrium. This aspect of the construction is shown to be related in a simple way to the familiar “external diseconomy” situation in which a free resource is allocated among alternative uses by equating average, rather than marginal products. The existence of an infinite class of models in which the associated planner's optimum and laissez-faire equilibria are equivalent follows naturally from the standard theory of the private and social costs of highway congestion. The model leads naturally to exponentially falling population distributions which exhibit an “urban-suburban” dichotomy, to a particular overall city size, and to an optimal allocation of land between transport and residential uses.     

城市道路交通拥挤收费的实践及对我国的启示

拥挤收费作为缓解城市交通拥挤的有效措施,其应用正逐步得到重视.文章介绍了新加坡、伦敦拥挤收费的实践,分析了这些实践活动对我国实施拥挤收费管理的启示.     

Competition and nationally optimum resource allocation under the presence of urban traffic congestion

The present paper compares the market city size and the socially optimal city size in a model which allows for traffic congestion. It establishes that under the assumptions of constant returns to scale and perfect competition for commuter train companies, market forces alone will produce optimality in traffic congestion, in resource allocation for traffic facilities, and in the city size. The notion of optimality in this paper is in the sense of maximizing the welfare of the entire nation, rather than that of the city residents.     

Highway congestion and congestion tolls

Highway congestion is ubiquitous. We model the speed-flow relationship, identifying private and social costs, and the implied congestion toll for a number of proposed formulations. Using data for a limited access highway, we estimate these speed-flow relationships and find that flow as a quadratic function of speed fits best. The unit of observation is the individual vehicle and flow is measured in terms of the vehicles which passed a point shortly before or after the reference vehicle. Maximum possible flow occurs at 30–35 mph and the congestion toll is infinite for slower speeds. Rush-hour drivers have greater speeds for a given volume of traffic and thus congestion tolls must vary by time of day.     

Branch network structure,authority and lending behaviour

Using a novel dataset of Ukrainian banks, this paper examines the link between the structure of branch network and bank lending. Bank regional branches are categorised into contact points without loan decision-making authority and more independent delegated branches which can make loan decisions. We find that a large and dispersed network of contact points can help increase credit supply and mitigate risks through diversification. Further, banks benefit from the information advantage brought by the presence of delegated branches in local markets. However, the longer distance between headquarters and local delegated branches, the more amplified agency problems become, which outweighs the benefits. Our findings suggest that the optimal structure could be a centralised network of delegated branches combined with a diversified access point network.     

The incidence of congestion and congestion tolls

In contrast with the enormous literature on efficiency aspects of congestion tolls, very little has appeared on their equity implications. Simulation is applied to a standard urban model to learn about the distributional aspects of an optimal toll, or the absence of one. Tolls are found to produce distributional changes which may overshadow their effects on allocative efficiency. In passing, the model is used to demonstrate that lagged supply adjustments to increases in the demand for suburban housing may be an effective, if second-best, alternative to congestion tolls.     

Isomorphic multiclass spatial price and multimodal traffic network equilibrium models

In this paper, we first show that a multiclass spatial price equilibrium model can be formulated as an equivalent multimodal traffic network equilibrium model with special structure. This connection allows us to obtain, for the multiclass spatial price equilibrium model, in a routine manner, any information that is currently available in the well developed theory of the general multimodal network equilibrium model, and moreover, to strengthen a number of these results taking advantage of the special structure of the equivalent multimodal traffic network model.     

Modeling the density variations of urban land uses with transportation network congestion

Perhaps the single most distinctive character of urban activity that distinguishes it from rural and regional activities is the intensive use of urban land. While the nature of density variations of urban land uses and their associated land rents are well understood, there have been few operational urban models that explicitly address the density variations of land uses. The paper presents a combined land use-transportation model, in which transportation congestion costs on networks of various transportation modes are simultaneously determined with the efficient intensity level of land uses. The procedure uses a nonlinear programming approach within the context of a multicommodity flow/input-output model.     

Traffic density,congestion externalities,and urbanization in China

ABSTRACT

Although there is an abundant regional literature analyzing traffic congestion, only a few studies have explored extending such analysis with spatial effects. This study uses a dynamic spatial Durbin model and city-level panel data for the period 2003–14 to investigate the spatial spillover effects of traffic congestion on urbanization in China. The results show that there is an inverted ‘U’-shaped relationship between urbanization and traffic density in local and neighbouring cities, and congestion effects have appeared. In the short and long run, the spatial effects of traffic congestion have become an important force restricting the effective promotion of urbanization in China.     

Heavy tails versus long-range dependence in self-similar network traffic

Empirical studies of the traffic in computer networks suggest that network traffic exhibits self-similarity and long-range dependence. The ON/OFF model considered in this paper gives a simple 'physical explanation' for these observed phenomena. The superposition of a large number of ON/OFF sources, such as workstations in a computer lab, with strictly alternating and heavy-tailed ON- and OFF-periods, can produce a cumulative workload which converges, in a certain sense, to fractional Brownian motion. Fractional Brownian motion exhibits both self-similarity and long-range dependence. However, there are two sequential limits involved in this limiting procedure, and if they are reversed, the limiting process is stable Levy motion, which is self-similar but exhibits no long-range dependence. We study simulations limit regimes and provide conditions under which either fractional Brownian motion or stable Levy motion appears as limiting process.     

Innovation,market structure and firm size: A simultaneous equations model

This study uses a hwequation model and data for four-digit SIC manufacturing industries to examine the joint endogeneily of output measures of innovation activity and market structure (industry concentration). Its results confirm recent studies finding high concentration to have a negative effect on innovation output (especially smabfinn innovations), and Anding that large-firm innovations and small-finn innovations respond Werently to economic and technological conditions. The study also reveals that, contrary to some previous research, and consistent with modern ‘Schumpeterian’ propositions, innovation output (especially largefirm innovations) has a significant positive effect on industry concentration.     

摩托车交通与城市发展相关问题研究——以广州市为例

摩托车交通是城市交通体系中的重要组成部分,随着社会的发展,摩托车所带来的问题也逐步凸显出来。在分析了摩托车的发展与国民经济的关系后,探讨了摩托车交通的发展对城市交通和治安安全、城市大气和噪音污染、其它交通出行的影响,结合广州市摩托车发展经验,提出了摩托车发展政策的相关建议,探求合适的摩托车交通发展战略,为城市交通的可持续发展提供规划依据。。     

Multivariate time series analysis of traffic congestion measures in urban areas as they relate to socioeconomic indicators

Traffic congestion has significant adverse implications for the environment and economy. Many state and local transportation agencies have implemented traffic congestion management practices to alleviate the negative implications of urban traffic. One of the major drawbacks of traffic congestion management practices is that they do not account for socio-demographic and economic factors, which have a significant impact on traffic congestion. Understanding the influence of these factors is very crucial because they can help to communicate the system's performance management and target setting. Only a few studies analyzed the relationship between traffic conditions (e.g., traffic demand and vehicular traveling speed) with a limited number of socio-economic factors. Moreover, most of the existing models ignore the temporal and spatial autocorrelations of traffic congestion, which may significantly limit their reliability and effectiveness. This study is developed with the purpose of identifying the most relevant external factors that affect traffic congestion performance measures. To conduct the research, we have used three urban congestion performance measures collected from 51 metropolitan areas across the U.S. over a four-year period, 2013–2016: travel time index, planning time index, and congested hours. We have used multivariate time series models to account for the complex inter-relationships among the performance measures and socioeconomic factors to identify the most influential factors affecting system performance. We have finally developed predictive models to estimate the traffic congestion measures using these factors. The results of rigorous modeling show that the factors influencing the traffic congestion measures are monthly average daily traffic (MADT), the number of employed, rental vacancy rate, building permits, fuel price index, and Economic Conditions Index (ECI). The prediction models indicated that the effects of these factors are statistically significant and could be used to forecast future trends in three performance measures accurately.