Quality of road traffi c in Japan is still unsatisfactory as the road network cannot achieve the desirable performance corresponding to traffi c and access functions of roads yet, and there remain a lot of subjects to be resolved in terms of road design and traffi c operations. The existing road network should be gradually improved and restructured as cost-effective, high-performance one, however, the conventional highway planning and design methodology can be considered to hardly achieve it. For that, practical application of the "performance-oriented highway planning and design" policy is needed, which can flexibly adopt possible combinations of road design and traffi c operation schemes necessary for realizing target performance. In this article, for the special issue on "performance-oriented highway planning and design", its concept and research requirements are overviewed, as well as the structure of this issue.
The "Commentary on Japanese Road Structure Ordinance" is a book which narrates the "Japanese Road Structure Ordinance" and was revised three times from the original version published in 1960. This paper puts together and formulates the progress and interpretation of hitory of each revision. The main results derived are as below; the thought of road design is changed from the intent of national uniformity of road structures at the beginning to the flexible application of the ordinance regulations for suitable road design for the regional condition recently; hierarchy in road classification is not clear so that the target level of service and the methodology in design are not fully established yet; the contradiction caused in the treatment of demand and capacity as daily volume should be dissolved; and it is needed that the establishment of new proper standards of lane width, design speed, and so on in road design or traffic operation through confirmation of the course and conotation of the such standards setting.
The highway traffic congestion is one of the most important social and technical issues from the early days of motorization in Japan. Accordingly, the highway capacity has long been a major concern of traffic engineers, not only in research but also in practice, in order to alleviate the traffic congestions. Also, the concept of the quality of service of traffic flow and its proper understanding according to diverse conditions are crucial for implementing the performance-oriented highway planning and design schemes. This article therefore overviews the recent research works regarding highway capacity and quality of service particularly in Japan, after reviewing the state of the arts in bottleneck phenomena observed on Japan motorways and highways. And the future perspective of these research fields is discussed.
This study analyzes a relationship between hierarchical street allocation and the network performances and discussed a design methodology of an individual street as well as a street network. First, a network performance represented by the average travel distance and travel time is analytically studied using an idealized grid network and the result is applied to five existing cities to validate its usefulness. Second, to grow out of the current demand-dependent design methodology, some recommendations on a performance based street design are proposed in line with the above analytical result.
In this paper, an integrated speed-estimation model is developed based on empirical analyses for the basic sections of intercity multilane expressway un der the uncongested condition. This model enables a speed estimation for each lane at any site under arb itrary highway-alignment, traffic (traffic flow and truck percentage), and rainfall conditions. By combin ing this model and a lane-use model which estimates traffic distribution on the lanes by each vehicle type, it is also possible to es timate an average speed across all the lanes of one direction from a traffic demand by vehicle type under specific highway-alignment and rainfall conditions. This model is exp ected to be a tool for the evaluation of traffic performance for expressways when the performance me asure is travel speed, which is necessary for Performance-Oriented Highway Planning and Design. Regarding the highway-alignment condition, two new estimators, called effective horizo ntal curvature and effective vertical grade, are proposed in this paper which take into account the influence of upstream and downstream alignment conditions. They are applied to the speed-estimation model, and it shows increased accuracy of the estimation.
A divided two-way two-lane (TWTL) expressway crosssection was defined in the most recent update of Road Structure Ordinance in 2003. This novel structure is expected to contribute to saving building cost of rural expressways particularly with low traffic demands. However, since its speed performance is remained unclear, the expected target speed may not be realized under some road traffic conditions. This paper therefore aims to analyze impacts of various conditions on speed-flow relationships of the divided TWTL expressway sections by using vehicle detector data, towards implementing the performance-oriented planning and design policy. After extensive analyses on several influencing factors that affect speed performance such as heavy vehicle ratio and precipitation, speed-flow relationships under different conditions are finally formulated. By using the proposed formulae, speed performance of the TWTL expressway sections can be verified at the planning and design stage of highways.
In this paper, a methodology to evaluate impacts of implementing auxiliary passing lanes on the qulity of service of two-way two-lane (TWTL) highways is developed, by adopting follower density as a measure of effectiveness. It aims to quantitatively esti mate the performance of traffic flows to be realized dependent on the passing lane length and its spacing and to provide suggestions as a design guide. Relationships between passing lane length, one-lane section length and follower density are formulated by modeling the simulation results based on traffic fl ow surveys. And possible combinations of minimum required passing lane length and its spacing required for achieving the target performance are indicated. Furthermore, the expected qulity of service of traffic flow under seve ral typical design policies of 2+1 lane highways are evaluated by applying this concept.
Evaluation of impacts of congestion improvement scheme s on travel time reliability is very significant for road authorities since travel time reliability repr esents operational performance of expressway segments. In this paper, a methodology is presented to estimate travel tim e reliability prior to implementation of congestion relief schemes based on travel time variation modeling as a function of demand, capacity, weather conditions and road accident s. For subject expressway segmen ts, traffic conditions are modeled over a whole year considering demand and capacity as random variables. Patterns of demand and capacity are generated for each five minute interval by appl ying Monte-Carlo simulation technique, and accidents are randomly generated based on a model that links acci dent rate to traffic conditions. A whole year analysis is performed by comparing de mand and available capacity for each scenario and queue length is estimated through shockwave analysis for each time in terval. Travel times are estimated from refined speed-flow relationships developed for intercity expressways and buffer time index is estimated consequently as a measure of travel time reliability. For validation, estimated reliability indices are compared with measured values from empirical data, and it is shown that the proposed method is suitable for operational evaluation and planning purposes.
In recent years, numerous municipalities have anno unced plans for promoting compact city. However, even if the citizens that have car dependent lifestyle move from suburbs to city center, not all of them simply abandon that kind of lifestyle. An objective of this study is to clarify the effect of the compact layout city for reduction of environmental load by tr ansportation. The effect is analyzed considering the change condition of travel behavior before and after relocation and the influence of providing information for car use reduction by using research data conduc ted in the satelite cities in metropolitan area. It was clarified that providing information continuously and making an effort for car use reduction produce the desirable effect of CO2 reduction.
In this paper, the roles of transport-community cards jointly issued by a public transport firm and retails are investigated as a means to vitalize an obsolescence shopping center located in a middle of a city. When both the price of goods supplied by the retails and the transport fares affect the consumers' behavior, there exist pecuniary externality between the behaviors of the retails and transport firms. The introduction of a transport-community cards system enables to integrate a basket of goods and transport service into a single commodity; thus, the pecuniary externality can be internalized by price coordination. In addition, the paper clarifies theoretically that the transport firm initiatively decides the price of the transportation service and the retails transfer their incomes to the transport firm so that they are induced to jointly issue the transport-community cards.
The Russian oil and gas industry earns more than half of the Russian tax revenue and foreign currency, and has been playing the role of the backbone of the state economy through the eras of the Soviet Union and the Russian Federation. With the elongation of distance to the European market from the oil producing regions, starting from Baku in the era of Imperial Russia to the Second Baku (Volga-Ural) and the third Baku (West Siberia) in turn, the role of the oil pipeline system as the transportation infrastructure became more and more important and the deployment of pipelines has become one of the indispensable pillars of oil strategy. Now, the oil pipeline network is to reach the Pacific Ocean, which will enable Northeast Asia to be added as a destination for Russian oil, with a result of expanding influence for Russia in these regions. On the other hand, gas exports from the Soviet Union to Eastern Europe started in 1967 by constructing a trunk pipeline from Ukraine, which was extended to West Germany in 1973, overcoming the confrontation between the East and the West and becoming a regional stabilizer. The United States considered this pipeline as an energy weapon and criticized this deal by saying that when Soviet gas flows to Western Europe, its political influence must flow like the gas itself. However, the Soviet Union collapsed in 1991, while gas transportation continued without any disruption. This is evidence that the gas pipeline from the Soviet Union was purely for a business purpose and was not politicized. Recently, Russia is aiming to export gas to northeastern Asia, which is expected to be a new stabilizer in this region, although different types of diffi culties (especially about the method of determination of the gas price) still need to be resolved.
Shadows in remote sensing images often result in problems for various applications such as land-cover classification, change detection, and damage detection in disasters. Due to these reasons, it is very useful if the radiance of shadowed areas is corrected to the same radiance as shadow-free areas. In this study, a shadow detection and correction method was proposed. Shadowed areas were detected by object-based classification, using brightness values and a neighbor relationship. Then the detected shadowed areas were corrected by a liner function to produce a shadow-free image. The shadowed areas with different darkness were corrected with different ratios to improve the accuracy of the result. The spectral characteristics of sunlit and shadowed areas in a QuickBird image were studied and then the shadow-free radiance was obtained.
Fuel cost increase forces liner shipping companies to bear higher ship operation costs and subsequently a lager total cost. To cope with such a fuel cost increase, they attempt to reduce the ship speed to maintain the low operation costs, even resulting in increase of the transit time. This study examines effects of ship speed reduction on fuel savings as well as profit increase, by using a mathematical model for a container liner service network design with a consideration o f empty container repositioning. Throughout numeric al experiments for the Asia-North America trade, the ship speed reduction is effective in fuel cost savings. Furthermore, it was found that the reduction of ship dwell time at port offset the longer transit time resulting from the cruising speed reduction.
This paper proposes a new auction mechanism for implementing the tradable network permit markets. Assuming that each user makes a trip from an origin to a destination along a path in a specific time period, we design an auction mechanism that enables each user to purchase a bundle of permits corresponding to a set of links in the user's preferred path. The objective of the proposed mechanism is to achieve a socially optimal state with minimal revelation of users' private information. In order to achieve this, the mechanism employs an evolutionary approach that has an auction phase and a path capacity adjustment phase, which are repeated on a day-to-day basis. We prove that the proposed mechanism has the following desirable properties: (1) truthful bidding is the dominant strategy for each user and (2) the proposed mechanism converges to an approximate socially optimal state in the sense that the achieved value of the social surplus reaches its maximum value when the number of users is large.
This paper presents a new approach for dynamic es timation of origin-destina tion (OD) matrices based on Unscented Kalman Filter (UKF). The new approach, di ffers from most of the conventional approaches, does not assume linearity of the original nonlinear relationship between OD parameters and measurements. Instead, the nonlinearity is retained by representing th is relationship using dynamic traffic simulation. This eliminates the need to compute the assignment matrix an d offers some degrees of flexibility in selecting the traffic simulation model and incorporating speed as additional measurement variables. Preliminary results demonstrate the potential of the proposed approach and the contribution from using speed data.