South Carolina DOT’s Approach to Analyzing and Classifying Curves for Safety Planning Roadway Design Planning Session Jay Adams, Industry Consultant Bruce Aquila, Sr. System Consultant Wednesday October 28, 2015

Identify/Classify Curves on Statewide Data Set Problem Definition How Does the DOT: Identify/Classify Curves on Statewide Data Set Prioritize Safety Programs to Remediate Curve Safety Issues Quantify Safety Data and Performance Measures to Support Actions Road Safety Audits Passing Restriction Analysis 11/22/2018

Many States Lack Curve Data in DOT Data Sets Challenges Large Data Volumes Many States Lack Curve Data in DOT Data Sets DOT Safety Data is Related to Primary Routes and LRS Data Sets What is a Curve? When does it begin and end? (Spirals) 11/22/2018

Relate Extracted Data to States Data (ETL) Methodology: Approach Leverage TomTom Data Geometry Advanced Driving Attribution Extract Key Elements for the State Relate Extracted Data to States Data (ETL) Methodology: Identify Interpret Curve Information Determine Direction of Curve Processing tolerances (10 ft. radius difference) Group Resulting Curves Match Curve Points Generate Result Files Advanced attribution: Physical - Height, weight, length, width, weight by axle Operating – Hazmat, truck speed limits, truck maneuvers, idling and jake brake General – truck restrictions, truck preferred, immediate access Vehicle type - # of axles, # of trailers, no commercial vehicles Data Matching: Within 20 feet on main roads Advanced matching based on road names (i.e. middle of roadway only 1 match vs. at intersections) Processing tolerance manipulated at run time Ramps and some intersections have larger data discrepancies 11/22/2018

Curve table LRS Keys/Measures Curve Radius Curve Length Curve Types Results Curve table LRS Keys/Measures Curve Radius Curve Length Curve Types Geometry Attributes Descriptions ID The unique identifier for the roadway LRS_KEY_1…N State LRS Keys (Up to 4 columns to define the LRS key). Closest State maintained roadway will be selected. This will be NULL if a State Road is not within the defined search tolerance. BEGIN_MEASURE State LRS begin measure Closest State maintained road selected. Measure derived from interpretation of State LRS segment measures. END_MEASURE State LRS end measure column. Closest State maintained road selected. Measure derived from interpretation of State LRS segment measures. CURVE_RADIUS Curve radius derived from commercial data in feet Values from commercial data converted to a radius in feet. Acceptable radius values will be defined between 100 and 3,000 feet. CURVE_LENGTH Curve length derived from commercial data in feet. CURVE_TYPE Classification of curve (simple compound, reverse). GEOMETRY Curve geometry as defined in the TomTom data for reference. Geometry stored as Oracle SDO_GEOMETRY and projected into same coordinate system as State LRS feature. CURVE_TYPE Descriptions Simple One simple curve with straight roadways on with end Compound Two or more consecutive simple curves that arc in same direction Reverse Two or more consecutive simple curves that arc in opposite direction In cases where a compound curve meets a reverse curve the curves on either side of a reverse curve will be flagged as a reverse curve. 11/22/2018

©2013 Intergraph Corporation Safety Planning 11/22/2018 ©2013 Intergraph Corporation

Fewer Fatalities and Casualties Better Infrastructure Preservation Benefits Curves Look Accurate (Reflect DOT Data) Data Integrates into DOT’s Existing Safety Processes: High Density Crash Location Road Safety Audits (Identify Potential Projects) More Accurate Ranking of Locations Support Passing Restriction Safety Analysis Expedited HSIP Reporting Fewer Fatalities and Casualties Better Infrastructure Preservation 11/22/2018

Enterprise Safety Analysis Part of a Holistic Safety Analysis Program 11/22/2018

Thank You Bruce Aquila Hexagon Safety & Infrastructure Bruce.Aquila@Hexagonsi.com Jay Adams Hexagon Safety & Infrastructure Jay.Adams@ Hexagonsi.com