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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?

• >100 persons killed/day (>37,000 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

text

Text- node ID, x, y

MapBasic interpolation

program

MapInfo Crash Locations

CAD node file

MGE(unit conversion)

Text- node ID, lat, long

MapInfo Node Locations

Paper crash records

DB2- ID- from node- to node- distance- crash information

MIF

ArcView Crash Locations

x’

y’

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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- ...

Crash Information

Paper crash records

MapBasic defines 3 tables A, B and C

MapInfo

text

MIF

ArcView Crash Information (for ArcView-ALAS)

text

fortran

ABBBC

ArcView Crash Information (for Explorer-ALAS)

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Background DataIDMS Base Records (DOT)- ADT- pavement type- lane width- ...

CAD Roads (DOT)- State- County- Local

Text file- vertices- information

MapInfo/MapBasic aggregate to county level

MIF ArcView

CAD Hydrology (DOT)

DXFRail (BTS)

BTS preprocessor

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Avenue Scripts

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PC ALAS

PC ALAS

PC ALAS

GIS ALAS

GIS ALAS

GIS ALAS

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Logical Query

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Spatial Query

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Possible error

Error Checking

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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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Aerial photo integrationFile Request Search Report Analysis Defaults Help F1

View Details, Sorted by:Total Acc.

Fatal Acc.

Fatalities

Prop. Dmg.

Total Sev.

Total Inj.

13 Total Accidents4 Fatal Accidents8 Fatalities4 Injury Accidents2 Major Injuries3 Minor Injuries3 Possible Injuries5 PDO Accidents65 Total Severity2 Ran Stop Sign3 FTYROW From Stop Sign1 FTYROW Making Left-Turn3 Speed too Fast for Condition4 None Apparent

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