GIS-ALAS: Locating and Analyzing Crash Locations within a GIS Environment National Highway Traffic Safety Administration 1999 Region Seven Data Conference June 8-10, 1999

Why Crash Analysis Systems? n >100 persons killed/day (>37,000 in 1996) n 8.8 million crashes per year in USA n 2.3 million injuries n vast amount of uncoordinated data n powerful/low cost computing n potentially huge B/C source: NHTSA 1997

Past/present ALAS (PC-ALAS) n PC-based system n User-friendly interface, easy to learn n About 700,000 crashes over 10 years n Provides easy access to data n 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

Past/present ALAS

CAD Node Maps

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

GIS-ALAS Project Goals n Develop geographic/map-based ALAS n Use power of GIS n Portable, accessible, windows based n Free users from node maps n Statewide coverage n Supports highway safety analysis n Facilitate integration with other data

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’

Roadway and Crash Coverages

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)

Background Data IDMS Base Records (DOT) - ADT - pavement type - lane width -... CAD Roads (DOT) - State - County - Local Text file - vertices - information MapInfo/MapBasic aggregate to county level MIFArcView CAD Hydrology (DOT) DXF Rail (BTS) BTS preprocessor

Block Groups, Crashes, and Business Coverages

Alcohol-Related Crashes and Tavern Locations

Benefits of Customization n technology transfer - similar interface to PC-ALAS n users don't need to know (much) GIS n users don't need to be database experts – variable names and labels (e.g., 3 = icy surface conditions) n increased flexibility in interface (e.g., choosing crashes by selection box, link/node (as in PC-ALAS), or city/county/region) n enhanced display, e.g., standardized colors, defined zooms, "stacking" of crash points n standardized reports, e.g., for enforcement, engineering n easier to do queries across counties, regions, years, tables n works with relational data structure of crash files

Relational Data Structure of Crash Files

Avenue Scripts

Opening AV-ALAS

Opening View

Opening Tabular Data

Selecting Region

Selecting Counties

Selecting Cities

Selecting Cities within Multiple Counties Recounting Selected Crashes

Refining Search

Viewing Reports

Additionally... n Point location specifications – by node – by crash location – by link n Utilize GIS environment – logical queries – spatial queries – thematic maps – buffering – additional data sources – more...

Logical Query

Spatial Query

Thematic Map - Crashes by Time of Day

Thematic Map - Crashes by Age

Thematic Map - Crashes by Surface Conditions

Applications: Collision Diagram Software

Emergency Response Applications n Emergency response areas n Nearest facility/shortest path to crash n Impact of “Avenue of the Saints” on emergency response n CODES - linking crash and hospital records

Emergency Response Times

Aerial photo integration

GIS Projects

GIS-ALAS