When a traffic queue forms all around a single grid road network and it causes a capacity reduction of the network (gridlock phenomenon), measures to relieve the gridlock phenomenon and recover the reduced capacity by controlling the road infrastructure are discussed in this paper. Controlling the road infrastructure is to adjust the merging ratio of an intersection on the single grid road network given to the traffic on the link which constitutes the single grid road network so as not to satisfy the occurrence condition of the gridlock phenomenon which the authors clarified in the past paper. Furthermore, long-term and short-term strategies are considered. The former one is the idea of selecting a controlled intersection from four intersections on the single grid road network with a viewpoint of maximizing throughput of the network when the traffic condition has stabilized after sufficient time has elapsed after introducing the control. The latter one is that with a viewpoint of maximizing increase of the throughput of the network immediately after introducing the control.
Existing urban space is constructed of a variety of streets that have the unique historical characters, for example old paths existing from pre-modern age, urban roads authorized in city plan, small allays built by urban sprawl. On the other hand, each street currently has usability on street network such as main street, commercial street, grid road in residential district. On planning street network, it is important to demonstrate the relation between these characteristics. The study field is Meguro Ward, Shibuya Ward and the periphery, where the urban area of Tokyo has exploded during modernization. In this study, we analyzed old edition topographic maps to identify the construction age of each street and applied Space Syntax to analyze the betweenness usability on street pattern. And then, we calculate the correlation ratio between these indices. As a result, it is revealed that older age streets have higher value of betweenness usability on neighborhood scale.
In Southeast Asia, there are unique transport modes: LAMAT which stands for locally adopted, modified and advanced transport. Although these are rooted as the legs of local residents, they often have no prescribed route and stop. Due to insufficient registration and management by local governments, LAMAT's actual operation and distribution are not clear in some countries. We developed a tool to detect LAMAT's car body from the satellite image data such as Google Earth and to estimate their distribution in the city using the method of R-CNN (Region with CNN). We verified the accuracy and the robustness of the developed tool by applying the tool to tricycle and jeepney along the actual street in Makati, the Philippines. We could grasp some factors that contribute to accurate detection and classification of LAMAT.
Evolution of hierarchical urban/regional system is observed in various spatial economic scales. This paper develops a multi-regional economy model with hierarchical (multi-scale) spatial structure and input-output linkages. We conduct numerical simulations to explore how the changes in interregional and intraregional transport cost affect the spatial distribution of economic activities. The results indicate that transport cost reduction causes re-dispersion from monocentric agglomeration, which is consistent with propositions in previous studies. We furthermore find some properties on industrial agglomeration patterns in the multi-scale spatial structure.
Community bus called “YuYu Bus” is operated in Kumamoto city, to support trip convenience improvement of public transport. It is served on public transport inconvenience area which is 500m ~ 1,000m away from a station and a bus stop, and the area with few demands. Therefore income and expenditure rates are low and it is difficult to continue service. Hence, there is a service continuation criterion of 30% of income and expenditure rates. The bus service is abolished if inhabitants of the bus route cannot achieve these criteria. In this study, we develop a travel demand model for community service which consists not only of trip frequency model representing the composition concept of ICF but also of individual mode choice model with consideration of social interactions. Using these models, we predict demands for community bus, and calculate income and expenditure rates. Also, we analyze relations between a route service levels and some environmental conditions which is needed to achieve a service continuation criteria.
The gridlock phenomenon in this study is defined as a condition in which a traffic queue forms all around a single grid (rectangular shape) road network and it causes a capacity reduction of the network without external intervention by the influence of downstream traffic queue on the throughput of an intersection of the network. When an isotopic condition is assumed, there are two resulting states after a traffic queue is formed all around a single grid network. On the other hand, one more traffic state can occur in an anisotropic condition. They are determined by the relationship between two parameters; the proportions of remaining traffic which makes right turn at the downstream intersection to the link traffic volume and the merging ratio of the downstream intersection. Furthermore, the proportion of remaining traffic at the downstream intersection to the link traffic volume changes in response to the traffic state of the link. In consideration of this transition under an anisotropic condition, the possibility of the occurrence of the phenomenon that the traffic flow suddenly falls and goes to deadlock, even though the traffic flow does not decrease when a traffic queue is once formed all around the network is indicated.
The present study investigates the impacts of the entry of large-scale retail establishments on the sales and exits of existing local grocery or clothing retail stores in Japan. Similar to related cases in Europe and the US, in Japan as well, the findings of the existing studies are mixed. We examine this topic using micro data from the Japanese Census of Commerce from 1997 to 2014. The difference-in-differences method is used by controlling for the retail establishments' self-selection bias in terms of location selection by the use of the demand potential function, used in new economic geography literature. The empirical results indicate that the impacts vary based on the periods (short term versus long term), distance from entry locations (distance bands), size of entrants (in terms of floor size), and type of existing stores (grocery or clothing). For clothing stores, the impacts are basically negative on their survival and positive on the sales of surviving stores, especially in the long term. The impacts are stronger when the distance from entry locations is less than 1000 metres. For grocery stores, the tendencies of the impacts are similar to those for clothing stores, but the impacts are estimated to be much weaker. Further, this study provides possible policy implications based on the results.s