1. Overview of the FHWA Pavement Friction Management Program Virginia Polytechnic Institute and State University Charles E. Via Jr. Department of Civil Engineering Edgar de León Izeppi

2. Outline Development and Demonstration of Pavement Friction Mgt. Programs: (FHWA DTFH61-09-R-00035 ) Objectives Background Research Team Research Plan Phase I & II Approaches for friction threshold level Center for Sustainable Transportation Infrastructure

3. Objectives (4 states) Determine criteria and methods, for investigatory (desirable) level and intervention (minimum) levels for friction and macro-texture for different demand/classes of highways. Assist in developing PFM Programs. Demonstrate state-of-the-art friction (and macro-texture) measurement equipment. Center for Sustainable Transportation Infrastructure

4. Background Goal: Reduce crashes (& fatalities) Evaluate recommendations of the 2008 AASHTO Guide for Pavement Friction. Major strategy is to determine investigatory/intervention threshold values, based on analysis of crash data & determine friction and/or macrotexture requirements Center for Sustainable Transportation Infrastructure

6. Source: International Road Traffic and Accident Database (IRTAD)

7. Center for Sustainable Transportation Infrastructure

13. Phase I Research Plan Center for Sustainable Transportation Infrastructure

14. Demonstrate state-of-the-art friction (and macro-texture) measurement equipment Center for Sustainable Transportation Infrastructure Source: Delane (2005)

15. Friction measurement equipment Center for Sustainable Transportation Infrastructure

16. Evaluation Criteria 1) Effectiveness predicting fatal crashes 2) Continuous measurement principle a) % Slip ratio (or equivalent) b) Type of tire c) Tire pressure (psi) d) Left-wheel path tire e) Right-wheel path tire possible 3) Macrotexture measurement a) Speed (kHz) b) Sampling distance 4) Commercially available 5) Robustness and readiness for deploy a) One operator capable b) Left side steering wheel available c) Complete package from supplier d) Vertical load (lbs.) e) Dynamic vertical load sensor Center for Sustainable Transportation Infrastructure

17. Evaluation Criteria (cont.) 6) Data collection productivity a) Typical water tank capacity (gallons) b) Range per tank (miles) 7) Measurement speed (recommended) a) Minimum/Maximum (mph/mph) 8) Precision a) Repeatability b) Reproducibility c) Length for the mean value (feet) 9) GPS-capable 10) Highway Software available 11) Other a) Highway track record (number of devices in use) b) Delivery time (months) c) Cost of the 2 year technical support and maintenance agreement Center for Sustainable Transportation Infrastructure

19. Phase II Research Plan Center for Sustainable Transportation Infrastructure

20. Different Approaches for setting investigatory (desirable) level and intervention (minimum) levels for friction and macro-texture Center for Sustainable Transportation Infrastructure

21. AASHTO Guide GPF friction threshold method Center for Sustainable Transportation Infrastructure

22. Alternative Approaches E.g., Model the probability of wet crash as a function of friction number using logistic regression Center for Sustainable Transportation Infrastructure

23. Investigatory Levels (UK)

24. Center for Sustainable Transportation Infrastructure Investigatory Levels (US)

25. edeleoni@vt.edu Questions ?