Geographic Information System-Based Accident Location and Analysis System (GIS-ALAS) Proposal

1.0 Project Statement

The Iowa DOT has developed an accident location and analysis system (PC-ALAS) that has been well received by users. With its pull-down menu structure, PC-ALAS is portable and more user friendly than its mainframe predecessor. Users can obtain accident statistics for locations during specified time periods. Searches may be refined to identify accidents of specific types or involving drivers with certain characteristics. Output can be viewed on screen, sent to file, or printed using pre-defined formats.

However, PC-ALAS remains rather difficult to use. Location "node numbers" must be identified from cumbersome node tables or paper/CAD maps. In addition, the presence of a node does not necessarily indicate the existence of historical accident data. Further, the text-based PC-ALAS does not utilize recent developments in computer graphics and spatial access methods such as geographic information systems (GIS).

We propose the development of a GIS-based ALAS. With advanced spatial query and display capabilities, a GIS-based system would reproduce current capabilities and, with marginal additional effort, enhance query and display features. Custom data requests will also be provided. Such a system, or GIS-ALAS, will include instant graphical access, enabling viewing and selecting of desired network locations (nodes and links). Node numbers no longer would need to be specified. Query results will be displayed on a map or in a table, thereby creating more easily understood displays of inputs (queries) and outputs (statistics).

2.0 Background

Interest in a user-friendly, fast, portable system for accident data retrieval and analysis is widespread. Several organizations have expressed a desire for a system that uses clearly defined inputs (queries) to create understandable outputs (statistics) in a timely manner. The outputs should be in the form of both graphics and tables. The Iowa Department of Transportation (Iowa DOT) Engineering Division, developer of the current PC-ALAS (accident location and analysis system), considers a GIS-based ALAS (or GIS-ALAS) to be a natural progression of its current product. Members of the Incident Management Subcommittee for the Des Moines Metropolitan Area Intelligent Transportation Systems Early Deployment Study have suggested that a GIS-ALAS would be beneficial to their study by providing accident data quickly and efficiently. And the Iowa DOT GIS Coordinating Committee has identified GIS-ALAS as a pilot implementation of GIS technology at the department.

Several ongoing efforts are relevant to the development of the GIS-ALAS. These efforts will be monitored and coordinated with project tasks. Key efforts include:

3.0 Literature Review

An extensive search of TRIS and other reference sources was performed, (see Section IX, Information Sources and References). Many of these sources were identified and reviewed as part of a recent ISU master's thesis on use of GIS for accident location and analysis (which resulted in the development of a demonstration GIS-ALAS). In summary, Iowa is certainly amongst the leading states with regard to the development of user-friendly statewide accident data systems. Some states are beginning to use GIS to store and access accident information. However, the particular structure of Iowa's accident databases as well as the multi-level jurisdictional access considerations make little of the other state's software and procedures directly transferable to the Iowa situation.

4.0 Proposed Research Methodology

We propose that the development of GIS-ALAS be staged into five sequential tasks, as follows:

4.1 Task A. (5%): GIS ALAS Research (Jan - Feb)

4.2 Task B. (40%): GIS ALAS Design (Mar - Jun)

4.3 Task C. (30%): GIS ALAS Development (Jul - Sep)

4.4 Task D. (15%): GIS ALAS Testing/Refinement (Oct - Nov)

4.5 Task E. (10%): Technology Transfer (Dec)

5.0 Project Products and Deliverables

The main product to be delivered is a working GIS-ALAS system for Iowa. Each of the following deliverables will be included in final report. Interim versions will be made available to the advisory committee. By task, the products are:

5.1 GIS ALAS Research Products

5.2 GIS ALAS Design Products

A description of GIS ALAS design considerations related to engineering and non-engineering applications. Included will be engineering applications that can/will use GIS-ALAS or be incorporated into the GIS ALAS as modules (University of Iowa, lead) as well as other potential applications.

An assessment of software capabilities (user friendliness, import/export, size, access, database design, etc.) that includes the approach to be used to incorporate GPS data and accommodate improvements in cartographic accuracy.

5.3 GIS ALAS Development Products

A description of the approach used to program the core system, data acquisition and assimilation, development of applications interfaces (modules), and development of access/distribution methods.

GIS ALAS documentation (technical and user)

5.4 (15%) GIS ALAS Testing/Refinement Products

A description of the identification of test subjects for each design criteria, feedback received from subjects and refinements to be implemented in GIS ALAS.

(10%) Technology Transfer Products

project report

software and documentation (technical and user)

GIS ALAS training (workshop)

selected plots from GIS ALAS (e.g., shaded density map of accident statistics for Iowa counties, etc.)

6.0 Project Duration and Phasing

One year effort, representing phase one of development. At the end of the first year, the GIS ALAS will be working for the entire state (subject to availability of CAD and data files). Subsequent years efforts will be dedicated to improvements and enhancements in the system and development of safety, engineering and related disciplinary applications of GIS ALAS.


Project Personnel


Information Sources and References

Available resources:

References from TRB-TRIS and other searches:


last modified on 27. January, 1997 by Michael D. Pawlovich (ISU/CTRE)

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