Dr. Zoltan Rado Biography

Dr. Zoltan Rado is the director of the Vehicle Surface Interaction research Center and the Crash Safety Research Center at the Pennsylvania Transportation Institute. His research interests include vehicle dynamics: vehicle surface interaction, dynamic frictional characteristics and braking; road surface characteristics; automotive-aviation safety: dynamic vehicle modeling and simulation, finite element analysis; and vehicle crash safety research; advanced vehicle technologies among many others.

Dr. Rado’s applied research initiatives include real-time prediction of aircraft landing dynamics, braking friction and stopping distance from flight data recorder information; winter runway friction measurement research (sponsored by NASA, FAA, Transport Canada, EU); investigation of the braking and frictional behavior of a several different aircraft types involved in runway overrun accidents (Norway, USA, Canada, Japan) worked with different organizations on aircraft braking and aircraft friction modeling and analysis (NASA, NTSB, JAA); a multiphase project to research, define and develop the next-generation highway maintenance vehicle (sponsored by Iowa DOT, Minnesota DOT and Michigan DOT); and the development of one-of-a-kind variable slip friction measurement research equipment; the research and design of special digital algorithms and filtering for inertial accelerometer and inclinometer systems for use in braking and vehicle dynamics research, design and development of ultrasonic and special “Light Slicing” measurement of surface texture for friction research; development of an integrated truck-based surface characteristics measurement system (for The Ministry of Transportation and Water Management, The Netherlands).

Dr. Rado is presently serves as the chair of:

  • Vice-Chairman of ASTM Committee E17 on Vehicle – Pavement Systems; Group II

  • Member of the ASTM E17 committee on Vehicle – Pavement Systems

  • Member of the ASTM F9 committee on Tires

  • European Committee for Standardization (CEN) – Member and Invited expert in European Committee for Standardization CEN/TC 227 Road materials / WG 5

  • World Road Association (PIARC) – Invited member of PIARC (World Road Association) Technical Committee on Surface Characteristics (C1)

Dr. Rado’s research background includes:

  • Winter runway friction measurement research sponsored by NASA, FAA, Transport Canada, EU;

  • Investigation of the braking and frictional behavior of a several different aircraft types involved in runway overrun accidents for Civil Aviation Administration in Norway, USA, Canada, and Japan;

  • Served as consultant to NTSB on aircraft accidents involving friction and aircraft braking

  • Aircraft friction analysis and braking modeling for NASA, NTSB, JAA and other international and national organizations

  • Research for Iowa DOT, Minnesota DOT and Michigan DOT for a multiphase multiyear research project to define and develop the next-generation highway maintenance vehicle based on surface friction and other characteristics

  • development of one-of-a-kind variable slip friction measurement research equipment for the Norwegian Road Directorate

  • Design and development of ultrasonic and special “Light Slicing” measurement of surface texture for friction research for FHWA

  • Development of an integrated truck-based surface characteristics measurement system for The Ministry of Transportation and Water Management, The Netherland

 

MEMBERSHIPS IN PROFESSIONAL ORGANIZATIONS

American Society for Testing and Materials

Vice-Chairman of ASTM Committee E17 on Vehicle – Pavement Systems; Group II

Member of the ASTM E17 committee on Vehicle – Pavement Systems

Member of the ASTM F9 committee on Tires

European Committee for Standardization (CEN)

Member and Invited expert in European Committee for Standardization CEN/TC 227 Road materials / WG 5

World Road Association (PIARC)

Invited member of PIARC (World Road Association) Technical Committee on Surface Characteristics (C1)

 

BRIEF LIST OF SELECTED PROJECTS

European Aviation Safety Administration (EASA) – Runway Friction Characteristics Measurement and Aircraft Braking

Dr. Rado was one of the Principal Investigators of the research project under EASA Contract No. EASA.2008.C46 for the Runway Friction Characteristics Measurement and Aircraft Braking (RuFAB) study, which was sponsored by the European Aviation Safety Authority (EASA) to investigate and harmonize:

  • Terminologies for runway surface conditions, related to functional and operational friction characteristics;

  • Functional characteristics as they relate to friction measurement reporting; and

  • Operational characteristics as they relate to runway surface condition assessment and reporting, friction measurement, and aircraft braking.

  • The overall objective of the work was to provide recommendations regarding the assessment of runway friction characteristics and Runway Condition Reporting (RCR).  This is a very broad subject; and thus, the project had several specific objectives, which may be summarized as follows:

  • To conduct a broad information-gathering effort to determine the current state of practice.

  • To compare the various approaches and definitions used for RCR and to suggest approaches for harmonizing them.

  • To compare the various approaches used for assessing functional friction characteristics and to suggest approaches for harmonizing them.  This included an evaluation of past approaches for harmonizing the readings from ground friction-measuring devices and recommendations for an updated device equivalency table (to Table A-1 in ICAO Annex 14, Volume 1).

  • To compare the various approaches used for assessing operational friction characteristics and to suggest approaches for harmonizing them.

 

Joint Winter Runway Friction Measurement Program

Dr. Rado has been involved in research projects that include a joint program between NASA and the Federal Aviation Administration to evaluate how well ground friction measuring vehicles correlated with the braking performance of aircraft under a variety of winter conditions. As part of this study tests were performed at various locations in the United Sates including the NASA Wallops Flight Facility, Norway, Japan, Germany, and Canada, with instrumented aircraft, a NASA B-737, B-757, B-767 and FAA B-727 as well as JAA B-747, Dornier and DeHaviland DASH-8 aircrafts. Ground vehicle friction data was collected before and after each series of runs with the aircraft. Several NASA, TDC and FAA reports were published documenting the test results and the relationships between ground friction measuring vehicles and braking performance of aircraft. A key result of this study was the establishments of criteria for providing adequate wet friction to aircrafts and being able to characterize aircraft braking performance using ground friction measuring vehicles.

 

16th Annual International Runway Friction Measurement and Calibration Workshop

Dr. Rado was the Principle Investigator of the project organizing and conducting the 16th Annual International Friction Measurement and Calibration Workshop Measuring.  The friction measurement workshop and conference provided a solid and fundamental basis for furthering the research to achieve the necessary significant advances toward solving harmonization, calibration and uncertainty problems in the data provided by friction measurement equipment. Methods of measurement and correlation of equipment have been analyzed and improved to increase measurement quality and remove uncertainties.

Objectives of the project:

  • Identify methods to improve harmonization between different measurement devices and test procedures used throughout the world

  • Prior to Workshop Establish and Prepare Test Surfaces

  • Select and prepare a minimum number of 7 different surfaces with different friction and texture characteristics

  • Use the DFTester and the CTMeter to establish the IFI, ESDU Harmonization Level and other Indices prior to workshop

  • Test different harmonization methods

  • Develop a comprehensive test matrix for the participant measuring devices that enables the determination of all harmonization parameters necessary

  • Execute the measurements for harmonization on the prepared surfaces at the LTI test track

  • Calculate the harmonization constants, repeatability and if possible reproducibility values for each device participating

  • Prepare harmonization certification sheets for participating devicesValidate Established Harmonization Values

  • Preselect airport surfaces in possibly two nearby airports ( one is adjacent to test track, one is 20 miles from test track) and establish harmonization index values

  • Execute simple repeated measurements with participating devices and test fidelity of harmonization methods and indices.

  • Analyze individual friction test equipment repeatability and reproducibility

  • Analyze equipment repeatability and reproducibility using harmonization methods

 

NCHRP Project 1-43 – Guide to Pavement Friction

Dr. Rado was a key researcher in the recent NCHRP Project 1-43 which was conducted to develop a guide for pavement friction aimed at assisting highway engineers in (1) understanding the issues associated with pavement friction and its importance to highway safety and (2) instituting pavement friction management and design practices and processes that optimize friction safety while recognizing other related factors. The research accomplished this objective by conducting a comprehensive review of literature and current practices, developing a practical approach to friction management and design based on the principle that an appropriate level of pavement friction must be maintained across all pavement sections within a given highway network, and preparing a guide that presents guidelines and recommendations for managing and designing for friction on highway pavements.  The information obtained in this project provided a basis for developing guidelines and recommendations for managing and designing for friction on highway pavements. This information was incorporated into a guide document prepared specifically for consideration and adoption by AASHTO.

 

International Experiment to Compare and Harmonize Skid Resistance and Texture Measurements

Dr. Rado was part of the research team and author of the research findings and report of this project.  The project involved an International Experiment (consisting of 41 friction and texture measuring devices that were evaluated at 58 different locations (highways and airfield runways) in Spain and Belgium between September and October 1992. The objective of the study was to determine:

  • Correlations between texture measuring devices.

  • Correlations between friction measuring devices.

  • Relationships between friction and texture according to different empirical and semi-empirical models.

  • Repeatability of each device.

  • Reproducibility between devices based on similar measurement principles.

  • Proposal of a universal standard for measuring and characterizing anti-skid performances of roads and airfield surfaces.

A key result of this study was the proposal for a common scale for measuring pavement skid resistance the International Friction Index (IFI). The advantages of the proposed index can be summarized as follows:

  • It provides a uniform means of reporting friction characteristics of pavements.

  • It allows measurements to be made using equipment currently in use by an agency.

  • It adjusts the valued provided by the traditional measurement to the common scale and allows for the retention of those traditional values to relate to historical data.

  • Since the IFI includes information on both friction and texture it is an improved tool for managing pavements. The IFI has since been developed and standardized by ASTM (ASTM E1960).

 

FEHRL Friction and Texture Measurement Relation and Harmonization Project

Dr. Rado has been involved in a number of research programs that investigated the relationships of surface texture, friction and friction measurement devices sponsored by the Forum of Highway Research Laboratories of Europe (FEHRL) where measurements, and analysis of friction and texture data and measurement device parameters have been investigated to derive harmonization models and measurement requirements between different types of equipment.  The research involved measurements taken with 14 different devices in Germany the Netherlands and Denmark.  Both macro-texture and friction measurements were collected on test and travelled road surfaces.  The project developed an alternate friction harmonization method based on the relationship between friction and texture characteristics of pavement surfaces as well the main measurement principles of different measurement techniques.  There were several reports and findings published based on these research and analysis.

 

Pennsylvania Department of Transportation, Evaluating Performance of Limestone Prone to Polishing

Dr. Rado was the Principal Investigator of the research project Commonwealth Of Pennsylvania Department Of Transportation Contract #510401 Evaluating Performance of Limestone Prone to Polishing.  In Pennsylvania several roads manufactured according to standard design and construction techniques and paved with portland cement concrete have shown unwarranted rapid friction (skid resistance) deterioration well before the expected time limits and reached dangerously low levels of frictional characteristics.  Based on preliminary studies it was assumed that these surfaces were constructed using Vanport limestone coarse aggregates.  A task force committee was formed to investigate the surface performance degradation and to recommend possible solutions for research.  Based on the committee’s investigation and recommendation, the following research objectives were developed and executed throughout the project.

The objectives of this project were to:

  • Using the outcome of the “Vanport Limestone Committee” (VLC), develop a research methodology to investigate the three priority recommendations of the VLC report for the solution of the problem.

  • Evaluation of the effect of blending Vanport limestone with different other aggregates.

  • Evaluation of the performance of different mortar fraction and aggregate concentrations.

  • Determination of the effect of coarse aggregate usage in top mortar layer on pavement friction performance.

  • Develop a test matrix to evaluate the effect of blending different aggregate materials in portland cement concrete using state-of-the-art laboratory test equipment for assessing surface characteristics and using accelerated wear testing for the evaluation of long-term pavement surface performance.

  • Develop a test matrix to evaluate the effects of different mortar fraction and aggregate concentrations in Portland cement concrete using state-of-the-art laboratory test equipment for assessing surface characteristics and using accelerated wear testing for the evaluation of long-term pavement surface performance.

  • Develop a test matrix to evaluate the effect of aggregate size in portland cement concrete using state-of-the-art laboratory test equipment for assessing surface characteristics and using accelerated wear testing for the evaluation of long-term pavement surface performance.

 

The New York State Thruway Authority – A comparison of key performance characteristics between longitudinal diamond ground and transverse tined pavement surface texturing for newly constructed PCC pavement.

Dr. Rado was one of the Principal Investigators of this study exploring frictional, textural and noise characteristics of the different surface finishes of PCC pavements.  The purpose of this study was to provide a comparison of longitudinal diamond ground and transverse tined pavement surface texturing for newly constructed Portland Cement Concrete Pavement (PCCP).

The study area was located along a test-section of I-190 in Buffalo, New York.  The two PCCP surface treatment types evaluated in this research project were compared based on safety, frictional and textural surface characteristics, noise, construction cost, service life, rideability, handling, and maintenance requirements.  The research also had conducted the initial evaluation and also analysis of follow-up noise and skid resistance measurements conducted approximately one year later.

 

BRIEF LIST OF SELECTED PUBLICATIONS

Books – Manuscripts

  • J. W. Hall, L.Titus-Glover, K.L Smith, L.D. Evans, Z. Rado, J.C Wambold, T.J Yager, “Guide For Pavement Friction” Transportation Research Board of the National Academies, 2007.

  • Wambold, J. C., Antle, C. E., Henry, J. J., Rado, Z., “International PIARC experiment to compare and harmonize texture and skid resistance measurements,” PIARC, Paris, France, 1995.

Articles

  • Zoltan Rado, Technical University of Hokkaido, Guest Lecture, “Correlation of Ground Friction Measurements to Aircraft Braking Friction Calculated from Data Flight Recorders” 2009

  • Zoltan Rado, Technical University of Hokkaido, Guest Lecture, “Vehicle/Pavement Surface Interaction and Impact of Skid on Crash Rates”, 2008

  • Zoltan Rado, King Mongkut’s University of Technology Thonburi Thailand, Guest Lecture, “Correlation of Ground Friction Measurements to Aircraft Braking Friction Calculated from Data Flight Recorders” 2008

  • Rado, Z. “Introduction of the International Runway Friction Index (IRFI)” Summer Winter Integrated Field Technologies Conference, 2007, CalgaryZoltan Rado, “Present status of International Runway Friction Index (IRFI),” SWIFT, Calgary Canada, 2007.

  • Zoltan Rado, “Simulation of Aircraft Landing and Braking Maneuver from FDR Data,” 2006 AIR SAFETY FORUM, 2006.

  • Z. Rado; J.C. Wambold, “Correlation of Ground Friction Measurements to Aircraft Braking Friction Calculated from Data Flight Recorders,” International Conference Surface Friction Roads and Runways, Christ Church, New Zealand, Proceedings, 2005, 2004.

  • Rado Z., Wambold J. C., “Aircraft Braking Friction Prediction From Flight Data Recorder Data” 2002 Federal Aviation Administration Technology Transfer Conference May 2002.

  • Rado Z., “Analysis of Road Surface Friction in Relation to Vehicle Braking Performance and its Application to PMS” Proceedings of the 1st European Pavement Management Conference, Budapest, Hungary, Sept. 28 2000. Vol 1.

  • Rado, Z., “Relation of Road Surface Characteristics and Vehicle Braking Performance” Proceedings of XXIII International Road Conference of the Baltic Road Council Pärnu, Estonia 25-27 August, 1997, Vol 1.

  • Rado, Z., “Aircraft Stopping Distance Ratio” Proceedings of the Joint Winter Runway Friction Measurement Program Toronto Canada 1998, Vol 1

  • Rado Z., “Aircraft Braking Performance Prediction from Ground Friction Measurements” Meeting on Aircraft Performance on Contaminated Runways, Montreal Canada, 29-31 October, 1997, Vol 1.

  • Rado Z., “Friction Dependency of state-of-the-art aircraft anti-skid braking algorithms and braking systems” SWIFT conference Calgary Canada, 1998, Vol 1.

  • Rado, Z. “Predicting aircraft stopping distance from ground friction measurements. Is it possible?” Proceedings of International Conference on Aircraft Performance on Contaminant Runways, Ottawa Canada, Oct. 1996 Vol 1.

  • Rado Z. “A new friction model of pneumatic tires and rough surfaces” SWIFT conference, Calgary, Canada, 1995, Vol 1.

  • Wambold J.C., Henry J.J., Rado Z., “Friction Measurement Techniques for Snow and Ice Operations” XIth International Winter Road Congress PIARC, 28-31 January 2002 – Sapporo, Japan.