GISALAS: Accident Location and Analysis System

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GIS-ALAS Accident Location and Analysis System

• Sponsored by the Iowa Department of
  Transportation
• Office of Transportation Safety

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Why Crash Analysis Systems?

• gt100 persons killed/day (gt37,000 in 1996)
• 8.8 million crashes per year in USA
• 2.3 million injuries
• vast amount of uncoordinated data
• powerful/low cost computing
• potentially huge B/C
• 
  source NHTSA 1997

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Past/present ALAS (PC-ALAS)

• PC-based system
• User-friendly interface, easy to learn
• About 700,000 crashes over 10 years
• Provides easy access to data
• Several Uses
• obtain accident statistics by time and location
• query database by accident/driver characteristics
• generate reports on-screen, to a file, to the
  printer

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Current Difficulties

• Node numbers must be identified from tables or
  paper maps
• Difficult to analyze patterns
• Does not readily support integration of
  additional data
• Hard to identify crash hot spots and to analyze
  causes and countermeasures

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CAD Node Maps
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Past/present ALAS
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GIS-ALAS Project Goals

• Develop geographic/map-based ALAS
• Use Power of GIS
• Portable, accessible, windows based
• Free users from node maps
• statewide coverage
• supports highway safety analysis
• facilitate integration with other data

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Software Selection

• GIS World list
• distribution
• development language
• vendor stability
• short list (pre-Geomedia)
• ESRI (ArcView, Arcview Publisher, ArcExplorer,
  MapObjects)
• Mapinfo
• Caliper (Maptitude)

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Software Selection (cont.)

• ESRI chosen
• ISU site license (low cost development)
• dynamic segmentation
• network analysis
• tech. Support (ISU GIS Facility)
• FHWA platform
• web application (MapObjects, Internet Mapper)
• ArcExplorer, ArcPublisher
• May migrate later

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Crash Locations
CAD node file
Text - node ID, x, y
Paper crash records
MGE (unit conversion)
DB2 - ID - from node - to node - distance - crash
information
Text - node ID, lat, long
y
MapInfo Node Locations
x
MIF
text
MapBasic interpolation program
MapInfo Crash Locations
ArcView Crash Locations
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Crash Information
MapBasic defines 3 tables A, B and C
MIF
MapInfo
Paper crash records
ArcView Crash Information (for ArcView-ALAS)
text
DB2 - ID - location information - A (crash)
records - B (driver 1) record - B (driver 2)
record - - C (1st 3 injuries) record - C (2nd 3
injuries) record - ...
text
fortran
ABBBC
ArcView Crash Information (for Explorer-ALAS)
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Background Data
IDMS Base Records (DOT) - ADT - pavement type -
lane width - ...
CAD Roads (DOT) - State - County - Local
CAD Hydrology (DOT)
Rail (BTS)
DXF
Text file - vertices - information
BTS preprocessor
MapInfo/MapBasic aggregate to county level
MIF
ArcView
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Avenue Scripts
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PC ALAS
GIS ALAS
GIS ALAS
PC ALAS
PC ALAS
GIS ALAS
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Logical Query
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Spatial Query
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Error Checking
Possible error
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Usability Study

• Evaluate capabilities
• Assess documentation
• Identify bugs and problems in data
• Identify differences between users' and
  designers' perceptions
• Report user difficulties
• Report on success of revision

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Phase II

• refine gis-alas and explorer alas
• currently building explorer ABBBC database (99!)
• working with past UNI work. future?
• intersection analysis capabilities (work with
  UI?)
• link-node lat/long conversion process
• assess avenue of saints as case study
• tech transfer, TRAINING!!! (how to use, why it's
  useful!)
• Jan - Oct 98

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Applications Collision Diagram Software Interface
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Emergency Response Applications

• Emergency response areas
• Nearest facility/shortest path to crash
• Impact of Avenue of the Saints on emergency
  response
• CODES - linking crash and hospital records

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