GIS-BASED ACCIDENT LOCATION AND ANALYSIS SYSTEM (GIS-ALAS) PHASE 2 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. PC-ALAS has a user-friendly interface and is easy to learn. Agencies can use the system to obtain accident statistics for specific locations and time periods, to query the database by accident or driver characteristics, and to generate reports to be sent to the screen, to a file, or to a printer.

In certain ways, however, PC-ALAS can be difficult to use. The "node numbers" of accident locations must be identified from node tables or paper maps and entered by hand. In addition, although PC-ALAS enables the user to access accident statistics for a given node, segment or area, it does not readily support the spatial analysis of accident patterns or promote the integration of additional data in these analyses. It is difficult to tell where the accident "hot spots" are and what can be done to remedy them.

GIS-ALAS is being developed to address these issues. In the Year 1997 effort (Phase I of a three-year sequence), this system was constructed to reproduce the current functionality of PC-ALAS and, moreover, to incorporate improved query and display capabilities. The graphical interface of GIS-ALAS allows the viewer to see on-screen maps of accident locations and to select specific nodes and links of interest with the click of a mouse. Paper maps and tables of node numbers are unnecessary, as is the manual typing of node numbers to do queries. The results of GIS-ALAS queries can be displayed, not only in tabular form but also in maps.

Phase 2 of the three-year GIS-ALAS effort is scheduled to begin on January 1, 1998. Phase 2 activities will focus on extending the usefulness of GIS-ALAS through the enhancement of its data integration, product delivery, user friendliness and analytical capabilities.

2.0 Background

The original PC-ALAS effort stemmed from a widespread desire for a user-friendly, fast, portable system for accident data retrieval and analysis. The product has been useful for the Iowa Department of Transportation (DOT), county and city engineers, municipal planning organizations, regional planning affiliations, law enforcement agencies, the Iowa Department of Public Safety, and the Iowa Office of the Federal Highway Administration. The intent of the GIS-ALAS project is to build on the success of PC-ALAS by making use of the spatial display, query, and analysis capabilities of geographic information systems. The DOT's Engineering Division, the developer of PC-ALAS, sees GIS-ALAS as a natural progression of the current system.

Early in 1997, a focus group was held with the GIS-ALAS Steering Committee and other interested individuals to review the status of Phase 1 of the project, and to discuss the capabilities of GIS-ALAS to be developed in future phases. Other meetings, both formal and informal, were held with the Steering Committee and other interested parties to investigate possible paths for the future development of GIS-ALAS.

The development of GIS-ALAS has been, and will continue to be, coordinated with relevant ongoing efforts, such as: PC-ALAS improvement activities; the collision diagram software project; coordinated management systems; and Officer Information Manager (OIM).

3.0 Proposed research methodology

Task 1: Continue refinement and enhance capabilities of GIS-ALAS (ArcView and Explorer Platforms).

Two tools have been built to provide easy access to crash data in a GIS environment. The first of these, Explorer ALAS, provides the user with a freeware system that allows viewing of crash data (A records) and background layers of information (roads with street names, highways, rivers, rail facilities and ALAS reference nodes.) The second, ArcView GIS-ALAS, has the functionality of PC-ALAS, as well as additional capabilities enabled by the use of GIS, such as mapping and spatial queries. Phase 2 will build on this first version of GIS-ALAS by incorporating additional refinements and enhancements. Several types of improvements will be addressed.

The interface will be improved and specific functionality will be added in response to input from users. This input will be gathered both during the technology training sessions/workshops at the end of Phase 1, and after the users have had time to work with GIS-ALAS or Explorer ALAS in their own offices. Typical improvements might include: changes to the menus and/or toolbars; additional query and report options; clarifications in the on-line and/or hardcopy documentation; and the removal of bugs or other potential technical problems. These improvements will be done for both distribution options, CD ROM and the Internet (Explorer only).

Additional data incorporation will be investigated in cooperation with the Black Hawk County pilot project team. This investigation will include a consideration of data in several different areas, such as road features, health care facilities, geographic borders (e.g., counties, census tracts), emergency response service districts, highway/rail grade crossings, aerial photos/digital ortho quads (DOQs)/digital elevation models (DEMs), and maintenance and emergency facilities. This task will also assess a tie-in to GPS and links to weather and other real-time information. Throughout this entire process, questions related to security and proprietary information will be considered.

Visual basic and MapObjects will be explored to see if a fully functional, freeware GIS-ALAS can be devloped. If within the scope of the resources of the contract, a prototype freeware product will be developed. In addition, GIS-ALAS will be ported to GeoMedia for use with the DOT standard GIS viewing software. If resources are available, user interfaces may be developed in visual basic for geomedia as well.

Task 2: Assess methods to identify accident rates for highway sections or intersections based on specific accident locations and traffic counts.

The calculation of segment-based accident rates can conceal patterns of specific accident locations within, or even between, these segments. For instance, accidents may be clustered in one part of a segment, or clustered near the endpoints of two consecutive segments. Moreover, the traffic counts used to calculate these rates may vary as one travels along a single segment. Other relevant roadway characteristics may also vary. The end result is that analyses of segments may miss important factors in the identification of accident problems, causes, and solutions. This task will assess the usefulness of the accident point locations of GIS-ALAS, and estimates of ADT variations along a segment, in providing finer-scale analyses of accidents.

Task 3: Enhanced procedure for link-node/latitude-longitude conversions

Two issues found to be relevant during the development of GIS-ALAS included: a) the location of accidents on curved line segments; and b) missing links. This task will address these problems. Also, the existing preliminary procedure to convert link-node locations to latitude-longitude will be extended to perform the reverse operation (i.e., to convert latitude-longitude to a link-node specification), so that accident records can be populated with both reference designations, until such a time when all accidents are recorded and located by latitude-longitude.

In addition, the use of GIS-ALAS or Explorer ALAS will be formally reviewed for assisting DMV traffic crash location efforts. If minor modifications can be made to improve this process and they are within the scope and budget of this contract, they will be made and a product delivered to the DMV. Preliminary discussions with DMV in integrating GIS-ALAS tools into the OIM will be conducted. Although development and refinement of such tools is beyond the scope of the current phase, additional work to support these activities may be negotiated as a result of these discussions.

Task 4: Changes in emergency response patterns due to the construction of the "Avenue of the Saints."

The Iowa State University Fire Services Institute will be undertaking a pilot project to assess the impacts of Highway 218 corridor relocation and expansion into the "Avenue of the Saints." The GIS-ALAS project team will work with the Institute to extend this pilot by developing methods in GIS to locate and allocate response resources, based on network and accident history information.

Task 5: Technology transfer

Training and documentation will be provided on the Phase 2 enhanced version of GIS-ALAS. In addition, the project team will outline the system requirements for maintaining the application once the project is completed. (A final set of requirements and recommendations will be provided at the end of Phase 3.)

4.0 Project Products and Deliverables

Listed by task, the products of the Phase 2 of the GIS-ALAS project are:

Task 1: Enhanced GIS-ALAS, Explorer ALAS and internet version.

Task 2: Evaluation of methods to compute accident rates, including point-based methods.

Task 3: Enhanced procedures for link-node/latitude-longitude (XY) conversions.

Task 4: Identify GIS methods to locate/allocate response resources for the Fire Services Institute's project.

Task 5: Documentation, training materials, and training.

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