Geographical information systems (GIS) can be defined as the integration of computer hardware and software to capture, manage, analyze and disseminate any kind of geo-referenced information.GIS provide comprehensive data for accessibility analysis since accessibility connect activities at one point of origin to the other point of destination through any mode of travelling to effectively manage demand and supply of goods and services.
While considering production and attraction of travelling between activity areas, transportation planning agencies can use travel demand modeling to produce data needed to make planning decision with trip distribution models used to establish travel characteristics of the region encompassing nature of transportation system, the characteristics of the travelers and land use patter of the region. GIS technology has the ability display graphics at the same time connecting the features with attribute tables making it suitable to maintain and upgrade the road network, which planners can manipulate to analyze deficiencies where demand may be exceeding capacity. This will help the highway planners to allocate scares roadway capacity to road users, identify other regions for capacity expansion, buffer areas inhibited by low income earners and allocating transport resources which can adequately meet their needs to control social effects of poverty.
Through buffet analysis, GIS technology plays a bigger role in providing emergency services to control the impacts of negative externalities like safety hazards, pollution and congestions. As acknowledged by( Waters, N.M. ,1999) , the absolute barriers like impassable rivers would be instrumental in calculating shortest path distance in conjunction with contours like a boarder crossing on movement cost to calculate least cost paths along networks .GIS create projects within impact area (buffer) and tests the impact of the project resulting into new travel routes and efficient pricing to control congestion and shorter time saving paths to respond to emergencies as contours will be showing travel time and major free ways within the impact area.GIS provide relevant information for transportation planner to come with long range plans derived from network analysis and travel simulation models considering frequency, convenience and speed of travel. The management will use this to project possible projects and services to transportation required to efficiently improve the mobility and accessibility for regional per capita growth.
According to (Overman ,H. ,2010), GIS will be still useful in spatial economy, since it will still be providing information to transportation planners in performing comprehensive cost benefit analysis in planning for future transport systems as they will be integrating land use trends, environmental conservations and energy consumption among others to come up with smooth and efficient transport systems. Engineering information systems for future projects design shall be provided by GIS when imagery elevation and environmental data are brought into CAD, financial software connected with design files in cooperated into GIS will be useful in projecting better labor ,materials and estimation of total cost of projects. Help in management of assets because asset mapping, project management and budgeting tools shall be used to account for construction and maintenance costs, tracking of task, work ,personnel and materials usage. To manage construction of new road networks, information such as schedules and assets shall be made abundantly available from the spatial interface with data from survey, soil, engineering drawings, geotechnical and environmental studies being organized. Mapping transportation networks to provide management solutions that integrate data from all forms of operartions.GIS will be instrumental in displaying crash records coupled with analysis of congestions, weather, and construction areas for safety mangers to evaluate causes of accidents and formulate effective prevention strategy.
Sustainable management of transportation infrastructure demands strict implementation of environment friendly solutions, GIS will enhance transportation planners’ ability to understand the impact of land use decisions in evaluating smart growth alternatives as it support the transportation infrastructure life cycle. Efficiently enhancing spatial economy by integrating transactions associated with flow of capital, commodities, information, parts or finished products through transportation network.
National Geographic Society (2012) GIS (geographic information system) geospatial information system retrieved from http://education.nationalgeographic.com/education/encyclopedia/geographic-information-system-gis/?ar_a=1
Overman, H. (2010) .Gis a job: what use geographical information systems in spatial economics retrieved from http://eprints.lse.ac.uk/30784/1/Gis_a_job_%28LSERO_version%29.pdf
Waters, N.M. (1999) .Transportation GIS: GIS-T. Retrieved from http://ggs.gmu.edu/People/Waters/WatersGIS-T.pdf