Comparing Simulated Safety Performance to Observed Crash Occurrence - PDF document

Comparing Simulated Safety Performance to Observed Crash Occurrence Flávio Cunto, Ph.D Universidade Federal do Ceará Frank Saccomanno University of Waterloo Outline Outline • Motivation • Objectives • Methodology • Major results • Concluding remarks 2

Motivation Motivation 1. The need for a more mechanistic analysis of risky situations 2. Traffic conflict data collection methods 3. Advances on microscopic traffic simulation models 4. Is there a relative validity between simulated measures of safety and crashes? 5. Linking Surrogate Measures of Safety to crashes would improve TC paradigm? 3 Objetive Objetive This paper describes an objective approach for linking simulated safety performance expressed in terms of the crash potential index (CPI/veh) to observed crash occurrence, with the primary focus being on rear-end crashes. 4

Microscopic Model for Safety Assessment Microscopic Model for Safety Assessment 5 Vehicle Interactions Vehicle Interactions Rear-end: Angled: 6

Crash Potential Index (CPI) Crash Potential Index (CPI) f(x) f(x) truck, dry car, dry pavement pavement DRAC MADR i,t 7 Microscopic Platform - - VISSIM VISSIM Microscopic Platform 8

Microscopic Platform - - VISSIM VISSIM Microscopic Platform 9 Linking CPI to Crash Occurrences Linking CPI to Crash Occurrences • Need very detailed traffic information • Test assertions: – Test 1: CPI over time (5min prior the crash) – Test 2: CPI crash x CPI non-crash (5min) – Test 3: CPI 1h x Crash rate (aggregated) 10

Test 1 Test 1 11 Test 2 Test 2 12

Test 3 Test 3 13 Concluding Remarks Concluding Remarks • Calibration/validation procedure for safety measures yield best estimates of simulation inputs • Tests for linking SP to observed crashes support assertion crashes occur when CPI is high • Microscopic approach proved to be useful in providing an objective measure of safety in practical applications 14

Future Work Future Work � Better vehicle tracking data � better models and more accurate analysis � More research regarding MADR � more inclusive model � Need to consider different road-users � Incorporation of safety into existing traffic simulation models 15 Acknowledgments: The National Council for Scientific and Technological Development 16

Thank you! Flávio Cunto flaviocunto@det.ufc.br 17