A GIS for Routing of Oversized and Hazardous Material Carrying Vehicles

A GIS for Routing of Oversized and Hazardous Material Carrying Vehicles

S K Datla
M-tech Student, Transportation Systems Engineering, Department of Civil Engineering,
Indian Institute of Technology Bombay,
Mumbai 400 076, India.
Email: depu_008@yahoo.com

R S Moorthy
Research scholar, Transportation Systems Engineering,
Department of Civil Engineering, Indian Institute of Technology Bombay,
Mumbai 400 076, India.
Email: moorthy@cidcoindia.com

K V Krishna Rao
Associate. Professor, Transportation Systems Engineering,
Department of Civil Engineering, Indian Institute of Technology Bombay,
Mumbai 400 076, India.
Email: kvkrao@civil.iitb.ac.in

1. Introduction
The Road Transport Officers (RTO’S) has the responsibility of issuing permits for oversize and overweight vehicles using the urban highways. Some of these vehicles transport super heavy loads in excess of 90,000 kg and with more physical dimensions. Figure 1.1 shows a vehicle that is representative of the type of vehicles for which routes need to be generated. The process for finding feasible routes consists of (1) the establishment of a tentative route with adequate width and height clearances; (2) a manual identification of all the bridges along the route; (4) Checking of each bridge to evaluate the adequacy of its structure; and (5) identification of an alternative route when at least one requirement is not satisfied ( Roberto et. al, 1999).

Hazardous materials (hazmat) comprise explosives, flammables, oxidizing substances, poisonous gases, and radioactive materials. By definition, they can be extremely harmful to environment and to human health, since exposure to their toxic ingredients may cause injury or death to plants, animals, and humans (Karkazis, 1995).

Figure 2.1 A over sized and over weight vehicle
Their negative effects are an apparently inevitable consequence of industrial processes dictated by the life style of a modern society. It follows that transporting these materials, often in populated or environmentally sensitive areas, is also inevitable. Reducing the potential negative impacts of transporting hazmat is an important task faced by communities, governments, hazmat producers and shippers. Routing hazmat wisely and designing safer networks for doing so are powerful means to achieve this end. A fundamental requirement of route design and assignment is to minimize the risk imposed by shipments traversing each link in a network (Jianjun, 2000). The procedure for finding the route consists of (1) Create buffers of specified widths (based on the type of chemical) for severe and less intense areas to all links. (2).Generate all available paths between origin and destination and find the total population coming in the buffer area by overlay. (3). Select the path which is having minimum population exposure. (4). Show the total population coming in each buffer (Mark et. al, 1998).

Considering the complexities in developing, updating, managing and processing of the transport network data, there is an urgent need to adopt new concepts of information technology in design and development of information system for efficient transportation network management. One of the software tools which satisfy the requirement is Geographical Information System (GIS). GIS provides the hub technology for planning, deploying, operating, and optimizing transportation systems. The use of GIS is increasing day by day. This increase is due to cheaper and faster data collection tools and the availability of high-quality commercial data sets. Transportation professionals can use GIS to integrate mapping analysis into decision support for network planning and analysis, vehicle tracking and routing, asset management, inventory tracking, route planning and analysis, and everything in between. After observing the advantages of GIS, the modules are developed in GIS environment (Mark, 1993).

To make the modules more realistic, Greater Mumbai was selected as the study area for present analysis. To develop the routing procedures for the study area, we have to build a GIS map along with network database. After completing map and database in GIS, modules were developed and attached. These modules are written in GIS developers Kit (GISDK) code and attached to the database using GIS-T software TransCAD. There are three ways to develop applications in GISDK such as Add-ins, Custom application and server applications. For the present work, modules are coded as Add-ins in GISDK. These are known as the resource files. Then the resource files are installed and complied in the GISDK custom application environment so that any layman can also use these facilities with minor introduction. On running the above developed macros, the macros will prompt the user to enter the required details through dialog boxes and gives the result.

2. Study Area and GIS Database Preparation

Study area
Greater Mumbai was selected as study area for present work. It includes geographical limits of Greater Mumbai (Up to Dahisar in the North, Mulund in the North-East and Airoli and Vashi in the East). The study area lies between 72E and 78E longitudes.

Zoning System
The zoning scheme for this study has been designed using 227 electoral wards of Greater Mumbai (refer Figure 2.2). Till now 88 Census sections have been used as zoning scheme since 1961 in all previous studies. The present study is designed with the help of 227 electoral wards, as the zones are very big and not homogenous in previous studies.

Network layer
The network built at 1 in 10,000 scales was obtained from a GIS company named Mappls. All major and minor roads which are having width more than 5 mts are considered for the analysis (refer Figure 2.3).

2.1 Preparation of GIS database
To perform routing analysis in GIS, different layers like zones, network layers with appropriate attributes are required. Present section describes the procedure involved in preparing GIS database.

Zonal layer and its attributes
The election commission of India has adopted 227 electoral wards in Greater Mumbai. But the census of India adopted 88 census sections. The zonal areas of these 88 census sections are very large. In all major projects conducted in the study area are with these 88 census sections. For the present study 227 zonal system is adopted by minimizing the area of each zone. Finding the exact population exposure in the buffer area is not possible, as the data regarding the exact building foot prints is not available. So, the population coming into the specified buffer is calculated by assuming the population in the zone is uniformly distributed. To minimize the error which is going to come by this approximation is minimized by dividing the area into smaller zones as shown in Figure 2.2.

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