IHSDM- HSM Predictive Methods Slide 1
Presentation Outline IHSDM Overview Relationship between HSM and IHSDM Crash Prediction Models and Data Needs IHSDM HSM Predictive Method 2011 Release Preview Questions / Discussion Slide 2
What is IHSDM? A product of FHWA s Safety Research and Development Program A suite of software tools that support project-level geometric design decisions by providing quantitative information on the expected safety and operational performance Slide 3
What Benefits does IHSDM Provide? IHSDM results help project developers make design decisions that improve the expected safety performance of designs IHSDM helps project planners, designers, and reviewers justify and defend geometric design decisions Slide 4
Evaluation Modules Crash Prediction Policy Review Design Consistency Intersection Review Traffic Analysis Driver/Vehicle Slide 5
Crash Prediction Module Scope Estimates expected crash frequency (i.e., Substantive Safety) based upon roadway geometry and traffic volumes Slide 6
Relationship between IHSDM and the HSM A. Introduction and Fundamentals B. Roadway Safety Management Process C. Predictive Method (IHSDM CPM) Chapter 10: Rural, Two-Lane Roads Chapter 11: Rural, Multilane Highways Chapter 12: Urban & Suburban Arterials D. Crash Modification Factors Slide 7
Relationship between IHSDM and the HSM FHWA intends IHSDM CPM to be a faithful implementation of HSM Part C methodology FHWA implemented all models based on HSM 1st Edition FHWA implemented Calibration Utility based on HSM 1 st Edition (to be released in Sept.,2011) Slide 8
Crash Prediction Models Highway Segments 2R MR U/SA 2-lane undivided (2U) 2-lane divided (2D) 3-lane w/twltl (3T) 4-lane undivided (4U) 4-lane divided (4D) 5-lane arterial w/twltl (5T) Slide 9
Crash Prediction Models Intersections 2R MR U/SA 3-leg STOP-control on minor 3-leg Signalized 4-leg STOP-control on minor 4-leg Signalized Slide 10
CPM Model Components Safety Performance Functions (SPFs) Crash Modification Factors (CMFs) Empirical Bayes (using crash history data) Calibration Factors and/or Site Data Enter via IHSDM Administration Tool Slide 11
CPM Data Needs Vary by highway type: 2-lane Rural Highways (2R) Multilane Rural Highways (MR) Urban/Suburban Arterials (U/SA) Highway Segment Data Intersection Data Crash Data (optional) Slide 12
CPM Data Needs - Segments ALIGNMENTS 2R MR U/SA Horizontal Complete Length (curves not needed) Vertical - Grades (VC s not needed) -Tangent Slide 13
CPM Data Needs - Segments GENERAL 2R MR U/SA Design Speed AADT Area Type Speed Designation Functional Class Slide 14
CPM Data Needs - Segments CROSS-SECTION 2R MR U/SA Cross Slope (Superelevation) Through Lane Auxiliary Lanes Turn lanes (2R, MR, U/SA) Passing/climbing lanes (2R) Shoulders TWLTL Median Slide 15
CPM Data Needs - Segments ROADSIDE 2R MR U/SA Driveway Density Driveway Locations and Types Roadside Hazard Rating Side Slopes On-Street Parking Roadside Fixed Object Density Slide 16
CPM Data Needs - Segments OTHER 2R MR U/SA Lighting Automated Speed Enforcement Centerline Rumble Strip Slide 17
CPM Data Needs - Intersections 2R MR U/SA Number of legs AADT s for Maj/Min Roads Type of traffic control Approach leg type (major/minor) Skew angle Approaches with exclusive left/right turn lanes Lighting Slide 18
CPM Data Needs - Intersections 2R MR U/SA RTOR (approaches prohibited) Left-Turn Signal Phasing Presence of Red Light Camera Pedestrian Volume (all legs) Max. Lanes Crossed by Peds Bus Stops w/in 1000 School w/in 1000 Alcohol Establishments (1000 ) Slide 19
CPM Data Needs - Crash History CRASH HISTORY DATA (Optional) 2R MR U/SA Segment-related Crashes Intersection-related Crashes Slide 20
IHSDM Demonstration IHSDM HSM Predictive Method 2010 Release (version 6.0.0; July 15, 2010) IHSDM HSM Predictive Method 2011 Release (version 7.0.0; Sept., 2010) Slide 21
Slide 22 Mainline: 2-lane undivided rural arterial 2.7 mi long 50 mph design speed AADT = 7000 vpd in 2010 11 ft wide lanes No shoulders 2-lane rural highway: AADT = 4500 in 2010 4-leg signalized intersection: Skew = 37 deg No turn lanes
Slide 23 Questions / Discussion
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Slide 27 Highway Editor Horizontal Alignment Data
Slide 28 Highway Editor Sample Curve Data
Slide 29 Evaluation Report (Output) Highway Segmentation
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Expected Crash Frequencies and Rates (Summary) Slide 31
Expected Crash Frequencies & Rates by Highway Segment Slide 32
Expected Crash Frequencies & Rates by Horizontal Design Element Slide 33
Expected Crash Type Distribution Slide 34
IHSDM Administration Tool CPM Calibration Data Sets Calibration Factors Calibration Site Data (HSM Calibration Process) CPM Distribution Data Sets Collision Type Distributions Crash Severity Distributions CPM Model Data Sets Includes SPF coefficients Slide 35
Calibration Factor Slide 36
Slide 37 Calibration Site Data
Slide 38 Calibration Site Data
Slide 39 Calibration Site Data
IHSDM 2011 Release (sept.,2011) May be downloaded free-of-charge at: http://www.ihsdm.org Technical support: E-mail: IHSDM.Support@fhwa.dot.gov Phone: (202)-493-3407 IHSDM Training: FHWA-NHI-380071 in NHI catalog at http://nhi.fhwa.dot.gov (2-day, on-site course) Instructor-led, web-based course under development Slide 40
Questions / Discussion For additional information: www.tfhrc.gov/safety/ihsdm/ihsdm.htm IHSDM Technical Support: IHSDM.Support@fhwa.dot.gov; (202)-493-3407 To download IHSDM software: www.ihsdm.org Shyuan-Ren (Clayton) Chen Clayton.Chen@fhwa.dot.gov; (202)-493-3054 Slide 41