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Safety Data Analysis Tools Workshop March 27-28, 2006 Uses, Benefits, and Current Status of GIS in Safety and Planning Applications Transportation Safety Planning Working Group
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2 GIS-Based Safety Management Systems Basis for development: Highway Safety Improvement Program o Collect and maintain safety data o Identify hazardous locations o Conduct engineering studies o Establish project priorities o Schedule and implement o Determine the effect of safety improvements Safety Analyst o Provide state-of-the-art analytical tools for use in the decision-making process to identify and manage a system-wide program of site-specific improvements to enhance highway safety by cost-effective means
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3 Benefits of GIS Collect data once, use many times Reduces data collection costs Improves data accuracy Improves data consistency Reduces data maintenance costs Reduces time needed to access data Promotes better decision-making for safety Improved public safety
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4 Conceptual Framework for SMS/GIS
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5 Inventory –collection/maintenance of all data elements Assess – process data, establish parameters, find locations Analyze – diagnose critical locations, establish costs/benefits Model – synthesize data into optimal resource allocation Evaluate – determine countermeasure effectiveness Program – develop implementation plans Publish – generate standardized and ad hoc reports
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6 SMS/GIS Functionality Functions InventoryAssessAnalyzeModelEvaluateProgramPublish
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7 SMS/GIS Functionality Functions InventoryAssessAnalyzeModelEvaluateProgramPublish
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8 Geospatial Data Inventory Purpose Collect/integrate safety & safety-related geospatial data Integrate into SMS database Safety data warehouse Types of Inventory Crash data (local, regional, statewide) Road inventory, including functional classification Traffic volumes Pavement data Road safety improvements (past, present, future) High crash locations Potentially hazardous locations
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9 Geospatial Data Inventory Data is most critical system element Data must be designed: To be feasible to collect/generate To be of sufficient quality To produce essential information Data design must be output driven What information is essential? What information will add value? Will the data produce this information?
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10 Geospatial Data Inventory Data: typically 70-80% of project cost Collection, aggregation Conflation, merging, etc. Quality checks Often neglected in technical specs Use of available data New data sources and capabilities Enhance data accuracy/timeliness Enlarge analytical capabilities
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11 SMS/GIS Functionality Functions InventoryAssessAnalyzeModelEvaluateProgramPublish
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12 Geospatial Data Assessment Purpose Characterize safety of roads, intersections, and network Compute accident rates for roads and intersections Develop safety rating index for roads and intersections Determine overall crash characteristics by type Aggregate safety rating for areas and locations Find locations indicated to be hazardous or potentially hazardous Data quality, conformance to standards Other potential assessment indicators
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13 Data for SMS/GIS Crash Data Varies significantly by state Standards within the State are required State/Local coordination is necessary to achieve standards for capture and data models Geo-location element is critical for success Standard naming conventions are also critical Use of a common base map Should use one of the standard LRMs Time stamp the crash date Current GIS approaches can locate to 1/100 mile
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14 Data for SMS/GIS Traffic Data Traffic counts are important They are used for crash rate calculations and other statistics They typically start as sparse point data and need to be filled in Data is needed for both State and local levels
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15 Data for SMS/GIS Hazardous Highway Features Blunt end guard rails Slippery pavement sections Narrow lanes or shoulders Non-break away signs supports Rigid light pole supports Inadequate horizontal or vertical curves Poor sight distances Non-uniform or inadequate traffic control devices Highway Classification Functional classification Number of lanes Divided or undivided Access control Type of area (urban, rural, suburban)
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16 SMS/GIS Functionality Functions InventoryAssessAnalyzeModelEvaluateProgramPublish
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17 Analyze/Diagnose Purpose - to generate: Identify anomalies Conformance to current standards Location statistical analysis Location summary reports o For location investigations Location visualization Crash report visualization Countermeasure development o Alternative strategies per location o System considerations Countermeasure cost Safety benefit determination
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18 SMS/GIS Functionality Functions InventoryAssessAnalyzeModelEvaluateProgramPublish
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19 Model/Optimize Purpose Optimize countermeasure strategy o Maximum possible benefit o Subject to funding limitation o Fit within feasible schedule Maximize benefit over entire network Model Effects on safety classification Countermeasure strategies Safety benefit Cost External priority Schedule Develop priority listings
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20 SMS/GIS Functionality Functions InventoryAssessAnalyzeModelEvaluateProgramPublish
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21 Evaluate Purpose Monitor the performance of the countermeasures Estimate countermeasure effectiveness Adjust collision reduction factors for countermeasures
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22 SMS/GIS Functionality Functions InventoryAssessAnalyzeModelEvaluateProgramPublish
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23 Program/Publish Purpose Transform technical allocations into real plans Develop multi-year program from modeling information Tabulate improvement, budget, and schedule Quantify projected improvements in safety To Publish Statewide safety program Statewide safety statistics Area safety statistics
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24 Pedestrian & Bicycle Safety Safe Routes to School Locations for new bicycle routes Pedestrian crash zones
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25 Pedestrian & Bicycle Safety Uses GIS data not typically captured in roadway inventories: Sidewalks Curb lane widths Crosswalk locations Applications: Shortest/safest/preferred routes Bicycle compatibility Location of high crash zones
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26 Analytical Tools National Cooperative Highway Research Program (NCHRP) Report 546 – Incorporating Safety into Long-Range Transportation Planning Appendix C – Safety Tools o Project level o Regional level o Corridor level Require differing levels of data and expertise Proactive and reactive Differing levels of analysis – more generalized to more detailed
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27 GIS at the State level 2006 AASHTO GIS-T Symposium Ongoing improvement in accuracy of geospatial data, particularly with road centerline databases Other data collected & maintained include: o Other transportation network features o Political & administrative boundaries o Geodetic control points o Orthoimagery o Elevation o Water features o Parcel boundaries
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28 GIS at the State level 2006 AASHTO GIS-T Symposium Respondents asked to list up to four current GIS activities Reponses were ranked based on cites GIS priorities determined The survey noted that: “GIS also seems to be used more frequently in specific analysis and planning application, particularly safety and crash analyses, environmental impact studies, and traffic and bridge management systems.”
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29 GIS at the State level GIS Activity# of Citations Development of web-based GIS application44 Linear referencing system development / enhancement15 Enterprise data warehouse14 Road inventory management system / attribute data13 Migration to new GIS hardware and software13 Road centerline database development / enhancement13 Data sharing partnerships / coordination12 Orthoimagery data collection / integration10 Traveler advisory / information system application10 Development of other geo-spatial databases10 Safety / crash analysis9 ITS / traffic management applications8 Project management applications8 Environmental / cultural mitigation applications7 Bridge management applications7 GIS strategic planning / needs assessment6 GPS data collection / integration5
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30 GIS at the MPO level AMPO Survey: Technical Priorities (February 2005) On a scale of one to ten, several broad categories, followed by more specific subcategories within each
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31 GIS at the MPO level Technical Resources/Solutions6.72 Best practices - planning practice and institutional issues6.82 Safe Streets6.29 Intelligent transportation systems6.22 Safety6.16 Transit-oriented and transit-ready development5.95 Context sensitive design5.91 Complete Streets5.85 Systems operations in general5.78 Security5.54
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Hilary Perkins, AICP, GISP Jacobs Civil, Inc. 314.335.4909 hilary.perkins@jacobs.com Many thanks to: Gerald Dildine ITIS-Corp
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Questions/Discussion
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