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?

>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

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

Past/present ALAS

CAD Node Maps

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

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

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

MIF ArcView

CAD Hydrology (DOT)

DXFRail (BTS)

BTS preprocessor

Block Groups, Crashes, and Business Coverages

Alcohol-Related Crashes and Tavern Locations

Benefits of Customization

technology transfer - similar interface to PC-ALAS users don't need to know (much) GIS users don't need to be database experts

– variable names and labels (e.g., 3 = icy surface conditions) increased flexibility in interface (e.g., choosing crashes by selection

box, link/node (as in PC-ALAS), or city/county/region) enhanced display, e.g., standardized colors, defined zooms, "stacking"

of crash points standardized reports, e.g., for enforcement, engineering easier to do queries across counties, regions, years, tables works with relational data structure of crash files

Relational Data Structure of Crash Files

Avenue Scripts

Additionally...

Point location specifications– by node

– by crash location

– by link

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

Emergency response areas

Nearest facility/shortest path to crash

Impact of “Avenue of the Saints” on emergency response

CODES - linking crash and hospital records

Emergency Response Times

Aerial photo integration

CTRE Crash Location Tool

Kansas City

June 1999

Outline

The National Model Current Iowa Location Procedure Advantage Safety Development and Demo

The National Model

Project Goal:• Shorten collection time

• Minimize traffic disruption

• Increase officer efficiency and safety

• Improve data quality

The National Model Projects:

– Data Collection Expert System

– GPS Location

– Crash Data Collection Process

– Smart Police Vehicle

– Systems Integration

– Technology Sharing and Assistance

Current Location Process

Current Data-Flow Chart

Central Office Location

Processing of Literal Description

Paper Officer Report

Paper Driver Report

ALAS

PC-ALAS

Access ALAS

Link / Node to XY

GIS-ALAS

Bottleneck

Advantage Safety

Proposed Flow-Chart

Central Office Location

Advantage Safety w/LocTool

(Enterprise)

Paper Officer Report

Paper Driver Report

ALAS

PC-ALAS

Access ALAS

GIS-ALAS

Advantage Safety

w/LocTool

(Mobile)

Advantage Safety

w/LocTool (Office)

Local Data Analysis XY to

Link / Node

Translator

Crash Location Improvement Crash location performed on-site or at local

office Geographic coordinates of crash Roadway information confirms location Key fields identified for base record ID and

future cartographic upgrade

ESRI MapObjects Microsoft Visual Basic Arcview Shape Cartography Data from DOT Spatial Data Warehouse (Oracle) Distributed as a DLL

Software Selected

User Interface Menu

Main Map Window

Coordinate Information

Location Tool GUI

Crash Locate Tool

Pan Map

Zoom In/Out

Previous View

View Entire Map

User Interface Menu

Coordinate Milepost CountyCity Intersection

Location Finders

Milepost Marker

Corporate Limits

Crash Location

Demonstration

Snap Location

www.ctre.iastate.edu

GIS Projects

GIS-ALAS