Masanobu Kii

Lengths of Double or Dual Left-Turn Lanes

Double (or dual) left-turn lanes (DLTLs) are a relatively new geometric feature, and the literature on their design parameters is limited. The effectiveness of the DLTL in improving the operation of an intersection depends on several design parameters; among them, the most critical is the length of the DLTL. A procedure for determining the length of the DLTL was developed. First, the procedure surveys how drivers choose a lane of the DLTL in the real world and analyzes the relationship between lane use and the volume of left-turn vehicles. Second, the procedure formulates the probability that all arriving left-turn vehicles during the red phase can enter the left-turn lanes; this means no overflow of left-turn vehicles from the DLTL and no blockage of the entrance of the DLTL by the queue of through vehicles. This probability is presented as a function of the length of the DLTL and the arrival rates of left-turn and through vehicles. The adequate lane length is derived such that the probability of the vehicles entering the DLTL is greater than a threshold value. Third, the adequate length is expressed in number of vehicles; later, this value is converted to the actual distance required on the basis of the vehicle mix and preference between the two lanes. Recommended lengths are presented as a function of left-turn and through volumes for practical application. The proposed approach is unique in that it avoids lane overflow and blockage of lane entrance.

Lengths of Turn Lanes on Intersection Approaches: Three-Branch Fork Lanes—Left-Turn, Through, and Right-Turn Lanes

This paper examines the lengths of turn lanes when a single lane approaches a signalized intersection and is divided into three lanes: left-turn, through, and right-turn. These three lanes help to increase the capacity of the intersection by allowing more vehicles to enter the intersection during the green phase. The question is, What is the appropriate length of each turn lane? The vehicle queue pattern at the entrance to the turn lanes is examined first. The following conditions prohibit an arriving vehicle from entering the desired lane: (a) lane overflow (the lane is too short to accommodate all turning movements) and (b) lane entrance blockage (the overflow of the vehicles from other lanes blocks the entrance of the lane, even though space is available in that lane). A set of formulas to compute the probabilities of these events is developed. The lengths are calculated so that the probability that a lane does not overflow and the entrance of the lane is not blocked is greater than a threshold value. Tables of the recommended lengths are prepared for different turn volumes and threshold probabilities. These lengths are found to be shorter than what is traditionally recommended. The presence of three lanes (left-turn, through, and right-turn) allows arriving vehicles to spread among different lanes, and thus the chances of lane overflow and blockage are reduced. This is noticeable when the movements among the three directions are nearly even.

Risk of Hunger Under Climate Change, Social Disparity, and Agroproductivity Scenarios

Considering the projected population growth in the twenty-first century, some studies have indicated that global warming may have negative impacts on the risk of hunger. These conclusions were derived based on assumptions related to social and technological scenarios that involve substantial and influential uncertainties. In this paper, focusing on agrotechnology and food access disparity, we analyzed food availability and risk of hunger under the combined scenarios of food demands and agroproductivity with and without climate change by 2100 for the B2 scenario in the Special Report on Emissions Scenarios. The results of this study suggest that (1) future food demand can be satisfied globally under all assumed combined scenarios, and (2) a reduction of food access disparity and increased progress in productivity are just as important as climate change mitigation for reducing the risk of hunger.

COMPARISON OF SUSTAINABILITY BETWEEN PRIVATE AND PUBLIC TRANSPORT CONSIDERING URBAN STRUCTURE

It is said that the car is convenient but consumes high-energy per passenger, while public transport is an environmentally friendly mode but needs high cost of investment and management. However, this view does not take account of urban structure such as population size and density. For instance, higher population density would cause congestion and consequent inconvenience for car usage. This may shift demand to public transport use. On the other hand, in a lower density of urban area, public transport attracts only a small passenger demand and thereby accounts for a high-energy consumption per passenger than private cars. The urban structure therefore can be the dominant factor for determining the effectiveness of urban transport. The urban structure is affected by the provision of transport infrastructure and its service level. In classical urban economic models, the location of agents and urban shape vary depending on the transport conditions. Therefore, the urban structure and transport effectiveness are inter-dependent. Even if the population size and density is the same, the efficiencies of private and public transport might be different due to the urban structure because of their historical pattern of land use and transport development. In this paper, we present the interaction between urban structure and transport using a simple urban-transport model. We also examine the sustain ability, measured by economic efficiency and environmental impact, of private and public transport in a hypothetical urban space. In this regard, it is specially focused on the path dependence of urban-transport interactions, and showed the possibility of multiple urban and transport situations. Several policy implications are proposed for utilizing the results of the models.

Projecting Global Urbanization and the Growth of Megacities

Purpose – The purpose of this chapter is to project the global emergence of megacities through the 21st century using population scenarios consistent with the Special Report on Emissions Scenarios (SRES) of the Intergovernmental Panel on Climate Change (IPCC). Methodology – A dynamic urban growth model is developed based on a scale-independent theory of growing networks taking into consideration the geographical and climatic suitability of the location of cities. The model is able to generate a series of megacity projections consistent with an experimental city size distribution based on a national urban population scenario consistent with Zipfs law. The model is applied to population projections for 45,316 cities around the world using three population scenarios from SRES. Findings – All of the projections indicate that a large number of megacities will be generated in developing regions towards 2100, although the range is wide and depends on the population assumed in the scenarios. Some results indicate an extreme population concentration in megacities; this might be undesirable for national security, quality of life, and sustainable development. Transport policies affect urban growth and national land development through changes in mobility and accessibility across the nation. Implications – The results presented in this chapter could serve to stimulate discussions on urban and national transport policies and planning, particularly in China.

Managing Urban Mobility Systems Through a Cross-Assessment Model Within the Framework of Land-use and Transport Integration

Purpose – The purpose of this chapter is to propose a cross-assessment model as an analytical tool for developing sustainable urban transport and land-use strategies for a low-carbon society. Methodology – A cross-assessment model is developed based on demand and supply models of transport services. The model is able to generate a set of the optimal service levels in public transport reflecting selected target strategies. It is applied to an impact analysis of public transport and land-use strategies in 2030 for all of Japans 269 urban areas,with outcomes – including the financial balance of public transport operation, user benefits and CO2 emissions reduction – compared among strategies and urban areas. Findings – The analytical results show that three value factors of efficiency, equity and the environment do not necessarily conflict with each other. In particular, it is clarified that CO2-emission reduction targets can contribute to the improvement of both financial balance and user benefits at the national level. In addition, the results of comparative analysis among the land-use and transport integration (LUTI) scenarios demonstrate that a combination of urban transport strategies and land-use control in the form of ‘corridors and multi-centres’ provides greater emission reduction and increased user benefits. Implications – The cross-assessment model developed in this chapter could serve as an analytical tool for strategic transport planning. The results in this chapter underlinethe benefit of LUTI strategies particularly in China.

Urban Planning Research in the Climate Change Era: Transdisciplinary Approach Toward Sustainable Cities

This article discusses the direction of urban planning policies toward sustainable cities. Sustainable development goals (SDGs) adopted by United Nations General Assembly range from poverty eradication, improvements in education to protection of global assets including oceans and climates. Achieving these wide ranging goals requires holistic and transdisciplinary approaches. Urban planning is one of the effective measures for SDGs because those goals are closely related with the urban activities. In this article, we first summarize a conceptual framework of the interaction between urbanization and climate change, and forecast the prospective trajectory of rapid global urbanization in this century and the consequent sustainability problems. Then, we discuss the direction of urban planning analysis to tackle the sustainability problems as sustainable science, and propose the cross-assessment approach for vision-led urban planning. The cross-assessment approach aims to explore synergistic solutions combining different value systems by assessing the impacts on a range of outcome indices of measures pursuing each value factor. The case studies for the cross assessment are taken from Japanese public transport policies. Finally, we discuss the impacts on urban expansion from socioeconomic changes and technological progress, especially in the fields of transport, construction, and communication.

Market Penetration of Safety-Related ITSs

One of the most active areas of research on intelligent transport systems (ITSs) is the study of how these systems improve vehicle safety and prevent traffic accidents. Although a number of safety-related ITS technologies have been developed, two particular technologies — the Roadside Information-Based Driving Support Systems (hereafter referred as to car-to-infrastructure systems) and the Inter-Vehicle Communication Type Driving Support Systems (hereafter referred as to car-to-car systems) — have attracted much recent attention. These systems differ from the autonomous detection-type driving support systems — such as automated following-distance control systems — in that they assist drivers in negotiating situations that cannot be easily recognized or cannot be visually recognized at all. A survey of Japanese traffic accident and traffic fatality statistics1 for fiscal year 2007 reveals that fully 86 per cent of all accidents in that year were altercations between vehicles, including rear-end collisions, right-angle collisions at intersections, and accidents occurring during left turns.2 Autonomous detection-type driving support systems offer insufficient promise of preventing such accidents, and for this reason the spread of car-to-car and car-to-infrastructure system technology is eagerly anticipated as an effective mechanism for significantly reducing the frequency of traffic accidents.

Economics of Intelligent Transport Systems: Crafting Government Policy to Achieve Optimal Market Penetration

In recent years, Intelligent Transport Systems (ITSs) have attracted increasing attention as revolutionary technologies for addressing the problems associated with mass automobile consumption, including traffic accidents, traffic congestion, and environmental pollution.

Future Directions for Fuel Efficiency Policy: Evolving from Fuel Efficiency Standards toward Indirect Regulations

In Chapter 2, we reviewed the trajectory of automotive technology advances — and the evolution of government technology policies — in post-war Japan, and we anticipated future directions for automotive technology innovation. Our conclusion was that, although we should consider expanding the use of economic measures, nonetheless the best way to guarantee the safety and reliability of future automobiles is to preserve and continue the existing regulatory structure in essentially its present form. In this chapter, we consider responses to the problem of global warming — a phenomenon which poses an urgent threat to the continued existence of human civilization — and reach a dramatically different conclusion, namely, that direct government regulation of fuel efficiency, the primary policy mechanism that has been used to address global warming in the past, is a fundamentally inappropriate response to the critical problem of climate change. We begin in Section 4.2 with an introduction to the process by which automotive regulatory policy has traditionally been crafted in Japan; we note that the content of regulations, and the standard levels they mandate, have traditionally been fixed through tight-knit collaboration between industry, academia, and government, and have been designed to minimize the likelihood of any car-maker failing to meet regulatory standards or being forced to withdraw from particular markets.