There is a growing concern that wild bears encroach into cities in Japan, which has adverse impacts on agriculture and human safety. This paper theoretically analyzes the socially optimal land use policies, such as regulating total area of residential and agricultural land and controlling the number of plants that is a main food source of bears, considering the following three externalities: (a) ecosystem services, (b) damages to agricultural products by bears, and (c) farmers’ fear of encountering bears. We find that, even if there exist these three externalities, the equilibrium size of residential area is consistent with the social optimum if bears do not enter the residential area, and that the optimal farmland size could be larger or smaller than the equilibrium size, which depends on the tradeoff between the loss in ecosystem services from expanding farmland and the decrease in the number of bears that have damages to the agricultural products and the farmers’ fear of encountering bears.
This study clarifies the effects of staggered work hours (SWH) on the urban spatial structure. To this end, we incorporate a model of firms’ work start time choice developed by Henderson2) into the traditional residential location model1). By utilizing the properties of a potential game, we show the following properties of the model: 1) workers employed by firms adopting SWH live farther to the CBD; 2) policies to encourage higher density near the CBD and to stagger work hours improve efficiency.
The objective of this research is to acquire knowledge of a method of arranging vehicle-weight measuring devices on a road network to efficiently collect information on “the traffic load from heavy vehicles,” which is a major cause of damage to the structures on roads. Three methods of arrangement (arrangement methods in I “traffic volume,” II “traffic path,” and III “traffic path and vehicle weight”) are proposed, and information such as the weight of individual vehicles and the start and end points of trips that have been collected in a road traffic census OD survey is used to compare and analyze the efficiency of the arrangement methods with respect to a real road network in the southern region of Chiba Prefecture. The results show that the amount of information about the traffic load obtained by selecting the locations of the arrangement on the basis of detailed information related to individual vehicles including “paths” and “weight” is generally quadruple that obtained by the method of selecting the locations of the arrangement on the basis of simplified information on each point such as “traffic volume.”
An air corridor is a kind of airspace concept where only the aircraft capable of self-separation can operate. Its installation is expected to increase the traffic capacity of the whole airspace, and aircraft flying inside it can reduce their fuel consumption and flight time. In contrast, aircraft flying outside it inevitably consume extra fuel and time in order to avoid the corridor airspace. In this study, the cost-benefit analysis is performed in order to clarify the feasibility and condition that the air corridor installation becomes beneficial. The operational cost increase of the flights outside the air corridor is analyzed as the difference between operational costs of the current trajectories and those of the trajectories modified to avoid the corridor airspace. The reduction of the operational cost by flying along the optimum trajectories inside the air corridor is also analyzed. Through an example analysis on the air corridor installation into the air traffic route from Fukuoka to Tokyo, the heaviest traffic in Japan, it has been found that even a small number of flights operated inside the air corridor can achieve the operational cost reduction larger than its increase per day.
This study analyzes the dynamic patterns of spatial congestion distribution and the Macroscopic Fundamental Diagrams (MFD) using the long-term observation data in the Tokyo Metropolitan Expressway network. We reveal that there are six typical types of spatial congestion distribution and that there exist regularities in the within-day transition processes among these distribution types throughout the year. In addition, we find that the shapes of the MFDs diﬀer according to the within-day state transition patterns, and a correspondence relation can be observed between each section of the MFD curve and the types of spatial congestion distribution occurring in that section.
Fujita and Ogawa’s (1982) spatial agglomeration model reveals that polycentric intra-urban configurations are formed as equilibria. Since the model admits multiple equilibria, some of them are unstable and impossible to realize under reasonable dynamics. Therefore, it is theoretically necessary to verify the stability of equilibrium solutions in order to select reasonable equilibria. However, to the best of the authors’ knowledge, no such study has been conducted so far. In this study, building on the theories of potential game and stochastic stability, we specify globally stable equilibria of the model in a linear city as well as a circular city. We demonstrate the following three characteristics of the model: 1) polycentric spatial patterns emerge as globally stable equilibrium; 2) the number of business areas in globally stable equilibria monotonically decreases with the decrease in transportation cost parameter; 3) both the linear city and the circular city share the above two characteristics in common.