A Prediction Accuracy-Practicality Tradeoff Analysis of the State-of-the-art Safety Performance Assessment Methods

Abstract

This study proposes advanced safety assessment methods in the perspectives of prediction performance and practicality. This study thus develops three different safety assessment approaches (simulated conflicts-incorporated, estimated conflicts-incorporated, and intersection operational attributes-based safety performance function) and utilizes two existing approaches (annual average daily traffic-based and simulated conflicts-based safety performance functions. These five safety assessment approaches are compared in terms of crash prediction performance at intersections and practicality representing the required efforts in implementing a method. The results showed that the simulated conflicts-incorporated safety performance function approach was best in terms of prediction performance while the annual average daily traffic-based safety performance function approach was best in the practicality aspect. The discussion on trade-off between prediction performance and practicality then followed based on the analysis on the prediction performance and practicality aspects. This study will be a reference to safety assessment practitioners when they need to assess safety on roadways and to select an appropriate safety assessment method with limited resources.

Keywords

Microscopic traffic simulation model ; Traffic conflict ; Surrogate safety measures ; Safety Performance Function (SPF) ; Accuracy-practicality tradeoff

References

1. AASHTO, 2010 AASHTO. (2010). Highway Safety Manual: American Association of State and Highway Transportation Officials.
2. ACHD, 2015 ACHD. (2015). Ada County Highway Districts traffic counts database, from http://www.achdidaho.org/Departments/Traffic/TrafficCounts.aspx.
3. Ahmed et al., 2011 M. Ahmed, H. Huang, M. Abdel-Aty, B. Guevara; Exploring a Bayesian hierarchical approach for developing safety performance functions for a mountainous freeway; Accident Analysis & Prevention, 43 (4) (2011), pp. 1581–1589
4. Al-Ghandour et al., 2011 M.N. Al-Ghandour, B.J. Schroeder, B.M. Williams, W.J. Rasdorf; Conflict Models for Single-Lane Roundabout Slip Lanes from Microsimulation; Transportation Research Record: Journal of the Transportation Research Board, 2236 (1) (2011), pp. 92–101
5. Cafiso et al., 2010 S. Cafiso, A. Di Graziano, G. Di Silvestro, G. La Cava, B. Persaud; Development of comprehensive accident models for two-lane rural highways using exposure, geometry, consistency and context variables; Accident Analysis & Prevention, 42 (4) (2010), pp. 1072–1079
6. Caliendo and Guida, 2012 C. Caliendo, M. Guida; Microsimulation Approach for Predicting Crashes at Unsignalized Intersections Using Traffic Conflicts; ASCE Journal of Transportation Engineering, 138 (12) (2012), pp. 1453–1467
7. Cunto and Saccomanno, 2008 F. Cunto, F.F. Saccomanno; Calibration and Validation of Simulated Vehicle Safety Performance at Signalized Intersections; Accident Analysis & Prevention, ELSEVIER, 40 (3) (2008), pp. 1171–1179
8. Cunto, 2008 Cunto, F.J. C. (2008). Assessing safety performance of transportation systems using microscopic simulation. University of Waterloo.
9. El-Basyouny and Sayed, 2013 K. El-Basyouny, T. Sayed; Safety performance functions using traffic conflicts; Safety Science, 51 (1) (2013), pp. 160–164
10. FHWA, 2010 FHWA. (2010). SafetyAnalyst: Software Tools for Safety Management of Specific Highway Sites, from http://www.safetyanalyst.org/docs.htm.
11. Garber and Rivera, 2010 Garber, N.J., & Rivera, G. (2010). Safety performance functions for intersections on highways maintained by the Virginia Department of Transportation.
12. Gettman and Head, 2003 Gettman, D., & Head, L. (2003). Surrogate Safety Measures From Traffic Simulation Models, Final Report . Federal Highway Administration (FHWA).
13. Gettman et al., 2008 Gettman, D., Pu, L., Sayed, T., & Shelby, S. (2008). Surrogate Safety Assessment Model and Validation: Final Report (U. S. D. o. Transportation, Trans.): Federal Highway Administration (FHWA).
14. IBM, 2013 IBM. (2013). IBM SPSS Statistics, from http://www-01.ibm.com/software/analytics/spss/products/statistics/.
15. ITS_Corporation, 2008 ITS_Corporation. (2008). SafetyAnalyst Users Manual. Turner-Fairbank Highway Research Center, McLean, VA .
16. Kirk and Stamatiadis, 2012 Kirk, A., & Stamatiadis, N. (2012). Development of Intersection Safety Exposure Estimates Through Conflict Models. TRB 91st Annual Meeting Compendium of Papers DVD 14.
17. Lee et al., 2013 Lee, J., Park, B., Malakorn, K., & So, J. (2013). Sustainability Assessments of Cooperative Vehicle Intersection Control at an Urban Corridor. Transportation Research Part C, 32 , 193-206.
18. Lord and Persaud, 2004 D. Lord, B.N. Persaud; Estimating the safety performance of urban road transportation networks; Accident Analysis & Prevention, 36 (4) (2004), pp. 609–620
19. Montella et al., 2008 A. Montella, L. Colantuoni, R. Lamberti; Crash prediction models for rural motorways; Transportation Research Record: Journal of the Transportation Research Board, 2083 (2008), pp. 180–189
20. Montella and Imbriani, 2015 A. Montella, L.L. Imbriani; Safety performance functions incorporating design consistency variables; Accident Analysis & Prevention, 74 (2015), pp. 133–144
21. Nezamuddin et al., 2010 Nezamuddin, N., Jiang, N., Ma, J., Zhang, T., & Waller, S.T. (2010). Active Traffic Management Strategies: Implications for Freeway Operations and Traffic Safety. 90th TRB Annual Meeting Conference, Washington D.C.
22. Nordback et al., 2014 K. Nordback, W.E. Marshall, B.N. Janson; Bicyclist safety performance functions for a US city; Accident Analysis & Prevention, 65 (2014), pp. 114–122
23. Ott et al., 2012 S.E. Ott, R.L. Haley, J.E. Hummer, R.S. Foyle, C.M. Cunningham; Safety effects of unsignalized superstreets in North Carolina; Accident Analysis & Prevention, 45 (2012), pp. 572–579
24. Owen, 2010 Owen, A. (2010). Outline of GLMs, from http://statweb.stanford.edu/∼owen/courses/306a/glm.pdf.
25. Robertson, 1994 Robertson, H.D. (1994). ITE Manual of Transportation Engineering Studies. Prentice Hall, Englewood Cliffs, N.J.
26. Shahdah et al., 2014 U. Shahdah, F. Saccomanno, B. Persaud; Integrated traffic conflict model for estimating crash modification factors; Accident Analysis & Prevention, 71 (2014), pp. 228–235
27. So et al., 2015 So, J., Lim, I.-k., & Kweon, Y.-J. (2015). Exploring Traffic Conflict-Based Surrogate Approach for Safety Assessment of Highway Facilities. in press at Transportation Research Record, Washington D.C., United States .
28. So et al., 2014 So, J., Park, B., Wolfe, S.M., & Dedes, G. (2014). Development and validation of a vehicle dynamics integrated traffic simulation environment assessing surrogate safety. Journal of computing in civil engineering .
29. So et al., 2014a J.J. So, B.B. Park, I. Yun; Classification modeling approach for vehicle dynamics model - integrated traffic simulation assessing surrogate safety; Journal of advanced transportation (2014)
30. Sobhani et al., 2013 A. Sobhani, W. Young, M. Sarvi; A simulation based approach to assess the safety performance of road locations; Transportation Research Part C: Emerging Technologies, 32 (2013), pp. 144–158
31. Wu and Jovanis, 2012 K.-F. Wu, P.P. Jovanis; Crashes and crash-surrogate events: Exploratory modeling with naturalistic driving data; Accident Analysis & Prevention, 45 (2012), pp. 507–516