Shortest Route Finding using an Object-oriented Database Approach

The huge and complex road networks in a country make it challenging to find the best route for roaming around.  Therefore,  it is  necessary  to arrange  the data  in such  a  way  that  its retrieval,  especially a  part  of  the  road  or  road  sub-network ,  should  be  efficient  and  needless  data processing is avoided. This paper presents  an object-oriented road  network  database  model  in  which  we divide  the  road  into road segments and road network into road sub-networks, into levels  according to the administrative in  which  a  country  is  divided  administratively.  The implementation of the model for shortest route finding has proved that model is efficient and effective. Keywords: Geographic Information Systems, Dijkstra’s algorithm, Road Subdivision, Composite and Containment Hierarchie

How to prioritize bridge maintenance using a functional priority index

The progressive aging of civil infrastructures makes it essential to develop managerial tools and instrument for planning maintenance activities. As public entities, typically in charge of the management of infrastructures, have limited resources, it is crucial to define clear prioritization criteria. Addressing this need, this work introduces the usage of a functional priority index for ranking infrastructures on the basis of the impact of their closure. The impact is expressed in terms of induced travel delay for people due to path detour. To estimate this delay an analytical strategy is introduced and applied to assess the priority index on a sample of 290 bridges in Lombardy. Relevant information are gathered integrating two data sources providing information on the transportation network and on the travel demand, i.e. road network data and Origin Destination matrices. The results of this application show that the method enables the identification of the most critical infrastructures and the detection, for each bridge closure, of the most impacted areas of the region and the most impacted hours of the day

Data Models for Moving Objects in Road Networks – Implementation and Experiences

Paper deals with the specific LBS scenario – Fleet management (FM) and more specifically with systems for Automatic vehicle location (AVL). Well designed and implemented spatial data model for moving objects is one of the most significant elements of any AVL system. In practical applications the results of the latest scientific research are seldom applied, despite the fact that this area has been developing intensively for more than 20 years. The reasons for this are analysed in the paper. Short analysis of functionality of these systems is presented considering the impact of these functionalities on the implemented data model for moving objects and more specifically their impact on spatio-temporal component of the model. The paper especially reviews the possibility of using road networks as a basis for the representation of moving objects data models and a fact that these models are rarely used in practical applications. A solution overcoming this situation is proposed. The solution assumes transition from the system that is not based on road network to the system that is based on network. There are quite few research papers dealing with OSM data models. Therefore, a significant space in this paper is dedicated to the description of these models since OSM data can be valuable for this type of applications

Exploration of Walking Behavior in Vermont Using Spatial Regression

This report focuses on the relationship between walking and its contributing factors by applying spatial regression methods. Using the Vermont data from the New England Transportation Survey (NETS), walking variables as well as 170 independent variables are derived including some through spatial analysis with Geographic Information Systems (GIS). Among those independent variables, people’s lifestyle and perception of the built environment variables are included. A linear regression model is first established to serve as a base model for comparisons with spatial regression models. The results reveal that people’s lifestyle and perception of the built environment are significant variables explaining Vermonters’ walking behavior. Methodologically, the results reveal that no spatial effect is found and that there are no significant differences between the linear and spatial regression models. Therefore, the study concludes that it may be appropriate to apply traditional non-spatial statistical tools to analyze the relationship between walking and its contributing factors. However, the study suggests that researchers examine whether spatial effect exists in these inherently spatial behaviors before using only traditional statistics. This caution is particularly relevant as methods to estimate spatial models become more commonplace and easily available. The two spatial methods used in this report both reveal small but different challenges

面向实际车道的3维道路网络模型

亚洲国家,特别是中国的城市发展,立交桥、摩天大楼等日益复杂。传统基于道路中心线的道路网络模型在几何、时空语义属性、拓扑关系表达等方面都难以满足立体化交通需求。本文引入物理车道、虚拟车道和车道带概念,提出面向实际车道的多层次3维道路网络模型,重点分析该模型的数据库实现方法和实际车道拓扑构建、离散化、面向实际车道的寻径导航等关键问题。试验总结了该模型的若干明显特点如路网的多层次表达、灵活准确的车道拓扑控制等

Utilising Semantic Web Technologies for Improved Road Network Information Exchange

Road asset data harmonisation is a challenge for the Australian road and transport authorities considering their heterogeneous data standards, data formats and tools. Classic data harmonisation techniques require huge databases with many tables, a unified metadata definition and standardised tools to share data with others. In order to find a better way to harmonise heterogeneous road network data, this dissertation uses Semantic Web technologies to investigate fast and efficient road asset data harmonisation