Virginia Polytechnic Institute and State University Charles E

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

Outline Development and Demonstration of Pavement Friction Mgt. Programs: (FHWA DTFH 61 -09 -R-00035) l Objectives l Background l Research Team l Research Plan Phase I & II l Approaches for friction threshold level Center for Sustainable Transportation Infrastructure

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. l Assist in developing PFM Programs. l Demonstrate state-of-the-art friction (and macro-texture) measurement equipment. l Center for Sustainable Transportation Infrastructure

Background l l l 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

Center for Sustainable Transportation Infrastructure

Center for Accident Database (IRTAD) Source: International Road Traffic and Sustainable Transportation Infrastructure

Center for Sustainable Transportation Infrastructure

Center for Sustainable Transportation Infrastructure

Center for Sustainable Transportation Infrastructure

Center for Sustainable Transportation Infrastructure

Center for Sustainable Transportation Infrastructure

Center for Sustainable Transportation Infrastructure

Phase I Research Plan Center for Sustainable Transportation Infrastructure

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

Friction measurement equipment Center for Sustainable Transportation Infrastructure

Evaluation Criteria 1) 2) 3) 4) 5) Effectiveness predicting fatal crashes 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 Macrotexture measurement a) Speed (k. Hz) b) Sampling distance Commercially available 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

Evaluation Criteria (cont. ) 6) 7) 8) 9) 10) 11) Data collection productivity a) Typical water tank capacity (gallons) b) Range per tank (miles) Measurement speed (recommended) a) Minimum/Maximum (mph/mph) Precision a) Repeatability b) Reproducibility c) Length for the mean value (feet) GPS-capable Highway Software available 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

Center for Sustainable Transportation Infrastructure

Phase II Research Plan Center for Sustainable Transportation Infrastructure

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

AASHTO Guide GPF friction threshold method Center for Sustainable Transportation Infrastructure

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

Investigatory Levels (UK) Center for Sustainable Transportation Infrastructure

Investigatory Levels (US) Center for Sustainable Transportation Infrastructure

Questions? edeleoni@vt. edu