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Geographical Information System

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"Geographical Geographical"" because it primarily deals with geographical features; "Information Information"" because it can turn out information from data; "System System"" because it consist of many interrelated components (that do many things: retrieve, visualize, edit, store, query and analyse GIS data).

The terms GIS (Geographical Information System) is now invariability used to describe computerized systems, which comprise a digital map background and layers of additional information, which can be viewed in any desired combination and at any scale.

Many highway agencies have been using GIS for analyzing accident data.

This study is conducted in SULTANAH BAHIYAH ROAD INTERSECTION with the objective to explore the potential of  GIS in capturing, storing, updating, retrieving, displaying and printing data to road database accident.

GIS permits users to display database information geographically. It can also provide a common link between two or more previously unrelated databases. The most useful aspect of  GIS as a management tool is its ability to associate spatial objects (street names, milepost, route number, etc.) with attribute information (accidents, cause, etc.). Most of the documents reviewed consider the use of GIS in transportation under either for general data maintenance (primarily inventory of  transportation-related incidents) or for simple data analysis. In recent years, there has been much discussion about GIS technology and applications across a wide variety of settings. Moreover, there have been many GIS-related developments in transportation planning and engineering (FHWA, 1993; Lewis, 1990; Kim and Levine, 1996). The power of them is rooted in the fact that GIS allows inferences to be drawn about the spatial nature of the data. Examples of GIS applications in transportation include pavement management systems that work with road segments, optimal vehicle routing, Automated Mapping Facilities Management (AM/FM) used for infrastructure management, drainage design, traffic modeling and accident analysis, demographic analysis for funding justification, and the option of displaying any form of tabular data that has a spatial component.

The main problem in identifying the accident blackspot is to determine the highest rate accident locations and the causes of these accidents. This is because the recorded data were not precise enough to carry out the accident study. Some diagnosis system will only be done if the accident data were recorded systematically. The criterion which will be taking into account in identifying the accident blackspot are the accident location areas, types of  road where the accidents happened, the road geometry and the light factor.

 Step 1:

Collection and Compilation of Accident Data  Step 2:

Computerization and Processing of the Accident Records.  Step 3:

Identification and Prioritization of the Accident Blackspot Locations.  Step 4:

Blackspots Prioritization and Diagnosis  Step 5:

Evaluation Techniques

Step 1: Collection and Compilation of Accident Data The first step in the production of the national database was the compilation of the accident form in the respective Police Districts. The forms were stocked temporary in a special storeroom at Police Districts before they were dispatching to the Road Department JKR Kedah in Alor Setar.

Step 2: Computerization and Processing of the Accident Records The data input, processing and analysis framework is summarized schematically. The MAAP Version 5 has been designed and customized in line with the POL27. This package has been adopted as the standard analysis package for analysis accident blackspot problems in Malaysia.

Step 3: Identification and Prioritization of the Accident Blackspot Locations There are a number of the location identification systems that can be used for referencing the location of accidents. The location identification system can be based either on the road maps that are digitized and converted in DCM format or in MAAP textual output.

Step 4: Blackspots Prioritization and Diagnosis Ranking of blackspot could then be carried out such as: Ranking by Accident Maps, Nodal Analysis, Analysis on Link Accidents, Analysis on Cell Accidents, Ranking by Accident Point, Ranking by Accident Cost, and Kilometer-Post Analysis.

Step 5: Evaluation Techniques There is also a number of evaluation techniques currently used in evaluating safety interventions. The selection of each technique depends on the nature of  work, availability of data and precision required. Among the available techniques are the cumulative plot techniques, chi-squared before and after analysis and multivariate analysis.

The overview of the methodology for system development can be seen the below, and a brief description of each phase

With the proper setup of GIS System, the user or decision maker can retrieve, analysis, and display database on its spatial characteristics. GIS System is developed to provide the following functions: i)

The core functions are entering, searching and retrieving information from database.

ii)

Main supportive functions are Node Analysis and Distribution Plot.

iii)

Minor functions included are Searching Engine and Accident Ranking

As for future works, however, the system can be enhanced to provide more features in the following ways: i)

Adding multimedia capabilities such as the ability to store digital photographs.

ii)

Adding printing function which ability to print out the accident information.

iii)

Adding a function which able to capture the collision diagram of the accident.

iv)

Change the database in term of textual format to tabular format.

v)

Security guards co-operation is very important especially for the duty officer.

vi)

The co-operation from the person who involved directly or indirectly is very important too.

i)

A.R. Mahmud, R.S. Radin Umar, and S. Mansor (1998). A GIS Support System for Road Safety Analysis and management. Pertanika Journal of Science and Technology.

ii)

A. Yusof (2000). Accident Data Collection and Prioritization System of Accident Blackspot. 4th Malaysian Road Conference, Kuala Lumpur.

iii)

Royal Malaysia Police, Road Accident Statistics Malaysia 2010. Percetakan Nasional Malaysia Berhad, Kuala Lumpur, 2010.

iv)

Baguley C.J and R.S. Radin Umar (1994). The improvement of  accident data quality in Malaysia. 1st Malaysian Road Conference, Kuala Lumpur.

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