USA Banner
  U.S. flag
              An official website of the United States government Here's how you knowOfficial US Government Icon
              **Official websites use .gov**A **.gov** website belongs to an official government organization in the United States.
            Secure Site Icon
              **Secure .gov websites use HTTPS**
                  A **lock** ( A locked padlock ) or **https://** means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites. 
 U.S. Department of Transportation Icon United States Department of Transportation
 Search DOT
            Search
                    About FHWAFHWA Organization
                Headquarters Offices
                Field Offices
                Strategic Plan
                Business Opportunities
                Staff Directories
                Careers
                Highway History
                Contact UsProgramsAcquisition Management
                Civil Rights
                Federal Lands Highway
                Infrastructure
                Innovative Program Delivery
                Operations
                Planning, Environment, and Realty
                Policy
                Research, Development, and Technology
                Safety
                Browse by TopicsResourcesCore Highway Topics
                Federal Aid Essentials
                Automation
                Complete Streets
                Laws and Regulations
                Policy & Guidance Center
                Section 508
                Publications and Statistics
                Professional Development
                National Highway Institute
                Resource Center
                Accessibility Resource Library
                FHWA Research LibraryNewsroomPress Releases
                Speeches & Testimony
                Photos
                Videos
                Media ContactsMenu FHWA Highway Safety Programs Home
                        Safety
                        Safety Data Analysis & Tools
                        RSDP
                        RSDP Tools


            
            In This Section
        Safety Data Analysis & Tools
                Crash Modification Factor Clearinghouse
                Roadway Safety Data Program (RSDP)
                                Overview
                Data Driven Safety Analysis
                Data Management
                Safety Data Analysis Tools
                Local Data Integration
                Technical Assistance
                Case Studies
                Training
                Resources
                Highway Safety Manual (HSM)
                Model Inventory of Roadway Elements (MIRE) and FDEs
                Systemic
                                Overview
                Why Systemic
                Training
                Resources
                Road Safety Audits
                                Overview
                Benefits
                Legal Issues
                Steps of Conduct
                Training
                Resources
                
                FHWA GIS Safety Analysis Tools v4.0
**Description:**
        Many agencies use computerized crash analysis systems in which crash, roadway, and traffic data are merged and analyzed to identify problem locations and asses the effectiveness of countermeasures. This tool integrates those traditional systems with a geographical information system (GIS), which offers spatial referencing capabilities and graphical displays. This tool is a GIS-based platform that includes five separate programs to evaluate crashes:

**Spot/Intersection Analysis**: This program is used to evaluate crashes at a user-designated spot or intersection within a given search radius. The end result of this analysis is a report that lists the number of crashes by injury severity, crash cost, and other variables designated by the user. A graphic depicting the spot or intersection, search radius, selected crashes, and roadway identifiers is also produced and can be output as a hardcopy map.
	**Strip Analysis**: This program is used to study crashes along a designated length of roadway as opposed to a spot or intersection. The user must enter the route(s) of interest and the length of the segment to be used in the analysis. The end result of this analysis is a report with similar output to that produced for the intersection analysis and a graphic that can also be output as a hardcopy map depicting the strip, selected crashes, and roadway identifiers.
	**Cluster Analysis**: This program is used to study crashes clustered around a given roadway feature such as a bridge, railroad crossing, or traffic signal. Crashes within a user-defined distance of a feature are identified on all routes selected. If the number of crashes found is equal to or greater than the user-defined minimum threshold, the location is flagged and included in the results. The analysis report lists various summary statistics based on user inputs and produces a graphic that can be printed as a hardcopy map depicting the high-crash locations.
	**Sliding-Scale Analysis**: This program is used to identify roadway segments with a high crash occurrence. This program differs from the Strip Analysis program in that the analysis segment is not fixed, but rather slides along the route in an incremental fashion. The user defines the segment length and the increment length for analysis. If the crash rate of any strip meets or exceeds the user-defined threshold, the segment is extended by the incremental distance, and the process is repeated. A segment is ended when the maximum milepost of the route is reached or when the user-defined number of allowable extensions without a crash is exceeded. Based on other user-defined parameters, intersections can either be ignored, excluded based on a buffer around each intersection, or included without any buffer and inclusive of crashes within a specified distance on intersecting routes. The end result of the analysis includes a table showing the high-crash locations, along with a variety of summary statistics and a map showing these locations.
	**Corridor Analysis**: This program is used to locate high-crash concentrations within a corridor. Using traditional methods, segments along a specific route could be examined (e.g., by using the Sliding-Scale Analysis), but multiple routes within a corridor could not be linked and analyzed as a group. This program allows routes to be linked together in a manner that allows the analyst to assess the overall safety performance within a transportation corridor.The user can evaluate crashes at designated spots or intersections, along specific roadway segments or strips, clustered around a specific roadway feature, or within a defined corridor. All of the programs allow the user to produce results for all crashes or for a given subset of crashes that can be defined using any of the variables contained in the crash and roadway inventory files. The user can also perform additional ad hoc queries using the analysis and mapping tools in ArcView. Custom reports can be generated using the crystal Reports engine bundled with ArcGIS.
    
          **Tool Type:**
        Software
    
    
    
          **Owner Source:**
        federal
    
          **Sponsor/Owner:**
        Federal Highway Administration (FHWA)
    
        **Published:**
      1999
    
        **Availability:**
      The tool is available free of charge at the following link: FHWA GIS Safety Analysis Tools

The User Guide is available free of charge at the following link: FHWA GIS Tools User Guide

Additional information can be found at the following link: FHWA GIS Tools Summary Report. U.S. DEPARTMENT OF TRANSPORTATION

**Federal Highway Administration**

1200 NEW JERSEY AVENUE, SE

WASHINGTON, DC 20590

202-366-4000Subscribe to email updates
                    About
  

        
              About FHWA
                Careers
                Org Chart
                Staff Directories
                Work with UsPrograms
  

        
              Acquisition Management
                Civil Rights
                Federal Lands Highway
                Infrastructure
                Innovative Program Delivery
                Operations
                Planning, Environment, and Realty
                Policy
                Research, Development, and Technology
                SafetyPolicies, Rights, Legal
  

        
              About DOT
                Accessibility
                Budget and Performance
                Civil Rights
                FOIA
                Information Quality
                No FEAR Act
                Office of Inspector General
                Privacy Policy
                USA.gov
                Web Policies and Notices
                Web StandardsNews & Events
  

        
              Newsroom
                Press Releases
                Speeches & Testimony
                Media Contacts
                Connect with Us