Safety Data Analysis Tools Workshop

1. Uses, Benefits, and Current Status of GIS in Safety and Planning Applications Safety Data Analysis Tools Workshop Transportation Safety Planning Working Group March 27-28, 2006

2. GIS-Based Safety Management Systems • Basis for development: • Highway Safety Improvement Program • Collect and maintain safety data • Identify hazardous locations • Conduct engineering studies • Establish project priorities • Schedule and implement • Determine the effect of safety improvements • Safety Analyst • 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

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

4. Conceptual Framework for SMS/GIS

5. Conceptual Framework for SMS/GIS • 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

6. SMS/GIS Functionality

7. SMS/GIS Functionality

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

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?

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

11. SMS/GIS Functionality

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

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

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

15. 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 Data for SMS/GIS • Highway Classification • Functional classification • Number of lanes • Divided or undivided • Access control • Type of area (urban, rural, suburban)

16. SMS/GIS Functionality

17. Analyze/Diagnose • Purpose - to generate: • Identify anomalies • Conformance to current standards • Location statistical analysis • Location summary reports • For location investigations • Location visualization • Crash report visualization • Countermeasure development • Alternative strategies per location • System considerations • Countermeasure cost • Safety benefit determination

18. SMS/GIS Functionality

19. Model/Optimize • Purpose • Optimize countermeasure strategy • Maximum possible benefit • Subject to funding limitation • 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

20. SMS/GIS Functionality

21. Evaluate • Purpose • Monitor the performance of the countermeasures • Estimate countermeasure effectiveness • Adjust collision reduction factors for countermeasures

22. SMS/GIS Functionality

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

24. Pedestrian & Bicycle Safety • Safe Routes to School • Locations for new bicycle routes • Pedestrian crash zones

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

26. Analytical Tools • National Cooperative Highway Research Program (NCHRP) Report 546 – Incorporating Safety into Long-Range Transportation Planning • Appendix C – Safety Tools • Project level • Regional level • Corridor level • Require differing levels of data and expertise • Proactive and reactive • Differing levels of analysis – more generalized to more detailed

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: • Other transportation network features • Political & administrative boundaries • Geodetic control points • Orthoimagery • Elevation • Water features • Parcel boundaries

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.”

29. GIS at the State level

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

31. GIS at the MPO level

32. Hilary Perkins, AICP, GISPJacobs Civil, Inc.314.335.4909hilary.perkins@jacobs.com Many thanks to: Gerald Dildine ITIS-Corp

33. Questions/Discussion