Transportation Systems and Materials

Research Project Abstracts: 2006 - 2007

In-Vehicle Energy and Emissions Information System (IVEEIS)
H.C. Frey and N.M. Rouphail
National Science Foundation
01/03 to 12/07
The key objectives of this research project are to (1) develop a micro-scale predictor of energy use and emissions that is deployable at the individual vehicle level in real-time; (2) identify, compare, and evaluate alternate energy use and emissions sampling/reporting schemes that are appropriate at the vehicle and network levels; (3) develop and test a prototype In-Vehicle Energy and Emissions Information System (IVEEIS); and (4) formulate and assess the utility of IVEEIS in developing transportation design and control measures aimed at energy and emission management policies.

Non-Conventional Alternative Intersection Treatments Guide
J.E. Hummer
Vanasse Hangen Brustlin, Inc.
08/06 to 08/08
Heavy traffic flows at intersections present challenges to engineers regarding excessive delays and worsening safety performance. Major side effects also include pollution, wasted fuel, increased stress levels, and economic losses. Several innovative intersection designs that divert left turn movements and reduce signal phases have been studied by researchers and implemented by users, including continuous flow intersections, median u-turns, and superstreets. This study sponsored by the FHWA is to develop an informational guide for those designs that includes a design selection procedure, coverage on operational issues, geometric design considerations, pedestrian accommodations, safety estimations, cost assessments, and marketing materials.

Sign Deterioration Analysis Layout Plan
J.E. Hummer and W. Rasdorf
NC Department of Transportation
08/01/06 to 08/15/06
There is a need to better understand how the retroreflectivity of sign sheeting degrades over time in the field so that the NCDOT can better manage their sign assets. One way of obtaining this understanding is to establish a sign farm. While field measurement of in-place signs affords valuable data, there are uncontrollable factors that are faced when using only in-place signs (vandalism, natural damage, etc.). This project established a methodology and design for a sign farm in which a wide range of factors of interest can be fully controlled and measured. These include sign color, type, orientation, height, etc.

Pavement Marking Performance Analysis
J.E. Hummer and W. Rasdorf
NC Department of Transportation
7/07 to 06/09
With an investment of $1 million after five years of data collection, the NCDOT requested that NCSU develop a pavement markings research plan in order to analyze relationships between pavement marking retroreflectivity values and variables such as marking color, marking age, pavement surface, and AADT. Understanding retroreflectivity performance over time is important to establishing a pavement marking strategy that maximizes the material's service life and minimizes the replacement of pavement markings that still have sufficient retroreflectivity. Furthermore, this understanding will enable the NCDOT to implement management strategies that achieve the Federal standards for minimum pavement marking retroreflectivity.

Tensile Strength - A Design and Evaluation Tool for Superpave Mixtures
N.P. Khosla
NC Department of Transportation/FHWA
07/04 to 06/06
Tensile strength plays an important role in the performance of asphalt concrete. A minimum tensile strength value can be calculated at a given traffic for fatigue life and an allowable rut depth for rutting and can be used as an additional criterion for evaluating the moisture susceptibility of a mix. Thus, the original values of tensile strength of conditioned and unconditioned specimens along with TSR values should be employed in assessing the effect of water damage on the performance of pavements. This study will provide a simple, reasonable, and dependable method for mix design and performance evaluation of Superpave mixtures.

Development of APA Design Criteria for Surface Mixtures
N.P. Khosla
NC Department of Transportation/FHWA
07/04 to 12/06
The APA test is the most widely used simulative test to assess the rutting potential of a mixture. A comprehensive study will be conducted on all the surface mixtures used in North Carolina to develop the rut depth criteria. The correlations estimated using the data obtained from the APA and Shear tests would be used to develop the rut depth criteria for the APA test. This study will provide a simple and effective methodology and design criteria for using APA for Superpave mixtures. The rut depth criteria could be implemented for all the new surface mix designs and test contractor submitted specimens for compliance.

Performance Based Analysis of Polymer-Modified Emulsions in Asphalt Surface Treatments
Y.R. Kim
NC Department of Transportation
07/06 to 06/08
This project focuses on the performance evaluation of polymer-modified emulsions in asphalt surface treatments. Limited research and data exist on quantifying the overall performance of polymer-modified surface treatments and associated cost-effectiveness. This project will test the improvement in surface treatment performance resulting from modifying the emulsion with polymers and its cost-effectiveness, in addition to providing baseline performance information about standard surface treatments which will be most valuable in planning maintenance activities. Recommendations will be made on the selection of a proper surface treatment option based on existing pavement distress, traffic volume, and road functionality.

Local Calibration of the MEPDG for Flexible Pavement Design
Y.R. Kim
NC Department of Transportation
07/06 to 06/08
The objective of this study is to calibrate the NCHRP 1-37A Mechanistic-Empirical Pavement Design Guide with local data by developing a material database using typical layer materials (HMA and unbound materials) for flexible pavements in North Carolina. The scope of research includes both fatigue cracking and rutting. The primary products of the proposed research are the flexible pavement layer materials performance database and the MEPDG HMA performance model coefficients for typical North Carolina HMA mixtures. An additional product will be an implementation plan with instructions for modifying the MEPDG to incorporate the local coefficients. This plan will shorten the delay between the research and the implementation of the pavement design.

Development of a Virtual Testing Module for an Undergraduate Course on Materials Design
Y.R. Kim
LITRE Grant, North Carolina State University
01/06 to 08/07
The short-term objective of this project is to enhance the students' understanding of the behavior of asphalt concrete through virtual microstructure fabrication and virtual testing. The medium-term goals are to (1) help develop graduate-level asphalt materials courses into distance-learning courses and (2) help enhance student learning in other materials-related course in the department, and elsewhere in the university, state, and country.

Development of Traffic Data Input Resources for the Mechanistic-Emperical Pavement Design Process
Y.R. Kim, G. List, J. Stone, and W. Rasdorf
North Carolina Department of Transportation
7/1/2007-6/30/2009
The Mechanistic-Empirical Pavement Design Guide for New and Rehabilitated Pavement Structures uses nationally based data traffic inputs and recommends that state DOTs develop their own site-specific and regional values. NCDOT recently completed an implementation plan for adopting the MEPDG, and two of the critical implementation recommendations addressed new data collection requirements for site-specific truck classification counts, truck axle load spectra, regional average seasonal adjustment factors, and forecasting methods for axle loads, as well as truck class volumes. This research project addresses these NCDOT traffic data and forecasting needs for implementing the MEPDG.

Top-Down Fatigue Cracking of Hot-Mix Asphalt Layers
Y.R. Kim
NCHRP 1-42A, Subcontract from University of Florida
06/06 to 05/08
In this research, the viscoelastic continuum damage model implemented in the finite element program (VECD-FEP++) will be used to investigate the top-down fatigue cracking mechanism in hot-mix asphalt pavements. The VECD model and the dynamic modulus from the IDT test will serve as the primary experimental tools. The resulting VECD-FEP++ will be used to simulate the behavior of asphalt pavements with varying loading, environmental, and pavement factors. The results from the simulation will be investigated to develop mechanistic procedures to evaluate the top-down cracking propensity of asphalt pavement as a function of various factors and to predict the top-down cracking performance of asphalt pavement.

Development of Multi-axial VEPCD-FEP++ and its Extension to Indirect Tension Test
Y.R. Kim and M.N. Guddati
Federal Highway Administration
09/05 to 08/07
Over the past decade, the NCSU research team has been successful in developing HMA models that can accurately capture various critical phenomena such as microcrack induced damage, strain rate - temperature interdependence, and viscoplastic flow that is critical for high temperature modeling; the resulting model is termed the viscoelastoplastic continuum damage (VEPCD) model. The primary objectives of this research are to (1) extend the VEPCD model to multiaxial state of stress; (2) develop a three-dimensional finite element program with the multiaxial VEPCD model; and (3) extend the principles used in the VEPCD modeling to the indirect tension mode.

Calibration of Rutting Models for HMA Structural and Mix Design
R. Kim and M.N. Guddati
NCHRP 9-30A, Subcontract from Applied Research Associates, Inc.
11/05 to 10/08
The objective of this research effort is to recommend revisions to the HMA rut depth prediction model in the mechanistic-empirical pavement design guide and software developed in NCHRP Project 1-37A for consideration by the NCHRP Project 1-40 panel and the AASHTO Joint Task Force on Pavements. The recommended revisions will be based on the calibration and validation of distress models with measured materials properties and performance data from existing field and other full-scale pavement sections that incorporate modified as well as unmodified asphalt binders.

Development of the Asphalt Pavement Performance Prediction Methodology Based on the Viscoelastoplastic Continuum Damage Theory
Y.R. Kim and M.N. Guddati
Korea Highway Corporation
10/04 to 12/06
The primary objectives of this research are (1) standardization of test and analysis methods for the determination of viscoelastic properties and performance of asphalt mixtures; (2) development of the multiaxial viscoelastoplastic continuum damage (VEPCD) models using the indirect tension test and triaxial permanent deformation test; (3) development of the VEPCD finite element program (VEPCD-FEP++); (4) calibration of the VECPD-FEP++ using the data measured from the KHC Test Road pavements; (5) development of transfer functions for the 33 asphalt pavements in the Test Road; and (6) development of a user-friendly graphic interface for pre- and post-processing of the VEPCD-FEP++.

Comprehensive Performance Evaluation of Polymer Modified Hot Mix Asphalt Mixtures
Y.R. Kim and R.H. Borden
Korea Kumho Petrochemical Co., Ltd.
10/06 to 10/07
With the goal of accurate pavement performance evaluation, the PI and his co-workers at NCSU have been developing advanced models for hot-mix asphalt (HMA) mixtures under complex loading conditons. Over the past decade, they have been successful in developing material models that can accurately capture various critical phenomena such as: microcrack induced damage this is critical for fatigue modeling; strain rate-temperature interdependence; and viscoplastic flow that is critical for rutting evaluation The resulting model is termed the viscoelastoplastic continuum damage (VEPCD) model.

Performance-Based Mix Design For Lime-Modified Asphalt Mixtures
Y.R. Kim and R. H. Borden
Chemical Lime Company
08/06 to 12/06
The proposed research is designed to determine the optimum asphalt content of the Lsub mixture for the Charlotte lime test sections using performance testing. The performance tests to be used in this study include: Dynamic modulus tests at varying frequencies and temperatues; Direct tension tests at 5 degrees and 40 degrees C for the viscoelastoplastic continuum damage (VEPCD) model; and Triaxial repeated load permanent deformation tests at 55 degrees C.

Quantifying the Benefits of Improved Rolling of Chip Seals
Y.R. Kim
NC Department of Transportation
07/05 to 06/07
This research is aimed at "low hanging fruit," that is, relatively low cost changes in compaction procedures that could significantly improve the chip seal performance in North Carolina. The performance measures to be evaluated in this study include aggregate embedment depth, aggregate retention, skid resistance, bleeding, and rutting. The research approach utilizes the chip seal performance test methods that have been used and refined in the ongoing NC Department of Transportation HWY 2003-09 project, Optimizing Gradations for Surface Treatments. The experimental program involves both laboratory and field experiments.

Viscoelastoplastic Continuum Damage Modeling of Modified and Unmodified Asphalt Mixtures
Y.R. Kim
Dwight David Eisenhower Transportation Fellowship to Mr. Benjamin Shane Underwood
US Department of Transportation
09/04 to 09/06
The primary objectives of this research are to (1) characterize polymer-modified asphalt mixtures being tested under the Accelerated Loading Facility (ALF) at the Federal Highway Administration Turner-Fairbank Highway Research Center in McLean, Virginia. using the viscoelastoplastic continuum damage (VEPCD) model; (2) incorporate the VEPCD model into the finite element code (VEPCD-FEP++); and (3) calibrate the VEPCD-FEP++ using the pavement performance data obtained from the FHWA ALF testing.

Development of the Asphalt Pavement Performance Prediction Methodology Based on the Viscoelastoplastic Continuum Damage Theory
Y.R. Kim and M.N. Guddati
Korea Highway Corp.
10/04 to 12/06
The primary objectives of this research are (1) standardization of test and analysis methods for the determination of viscoelastic properties and performance of asphalt mixtures; (2) development of the multiaxial viscoelastoplastic continuum damage (VEPCD) models using the indirect tension test and triaxial permanent deformation test; (3) development of the VEPCD finite element program (VEPCD-FEP++); (4) calibration of the VECPD-FEP++ using the data measured from the KHC Test Road pavements; (5) development of transfer functions for the 33 asphalt pavements in the Test Road; and (6) development of a user-friendly graphic interface for pre- and post-processing of the VEPCD-FEP++.

Placement of Detection Loops on High Speed Approaches to Traffic Signals
G.F. List
NC Department of Transportation
07/06 to 06/08
At high-speed, signalized intersections, the placement of detectors is critical for safe and effective operation. Well-placed detectors and carefully chosen signal timing parameters, such as yellow and all-red times, can reduce the likelihood of both right-angle and rear-end collisions as drivers on the main road deal with dilemma zone issues - whether to slow down and stop or continue through the intersection. This project will explore the best placement of detectors on such approaches through a two-pronged effort involving modeling and field testing of alternative configurations. Recommended practices will be developed based on the modeling and field test results and benefit-cost analyses.

System of Systems Architecture Development Support
G.F. List
Sandia National Laboratories
10/05 to 09/06
Sandia National Laboratories is involved in projects requiring the implementation of the System of Systems (SoS) architecture. A significant compliment to this approach is in optimizing system components. The project is focused on providing expertise in formulating analytic and descriptive models that can compliment and/or be integrated into the SoS architecture.

North Carolina Truck Traffic Profiles
G.F. List, J.R. Stone, and B. Mei
NC Department of Transportation
07/06 to 12/08
Better trip profiles are needed to understand the extent to which heavy trucks are using the state's various categories of highways, from rural secondary roads to urban interstates. Pavement and bridge engineers need a better sense of truck weights and axle spacings. Investment decision makers and planners need a better picture of truck volumes, trip distances, and weight distributions by highway class and route category. To help meet these needs, this project aims to create better truck trip flow profiles.

Blind Pedestrian Access to Complex Intersections, Phase I
N. Rouphail and Richard Long (WMU)
National Eye Institute through WMU
07/05 to 05/07
A pedestrian crossing at roundabouts is initiated by a pedestrian upon detecting a crossable gap, a driver yielding to a pedestrian, or a driver stopping due to an external control mechanism (e.g., signal) that forces gaps to occur in the traffic stream. This program of work is focused on the development and behavioral evaluation of technologies that can detect or create these events and convey the fact that they have occurred to blind pedestrians. The study will extend recent work on induction-loop yield detection by developing and testing improved yield and gap detection systems that rely on video-zone detection technology.

Testing the Feasibility of a Video-Image Processing System for Tracking Signalized Arterial Traffic
N.M. Rouphail
National Institute for Advanced Transportation Technology (NIATT), University of Idaho
02/06 to 10/06
A prototype Video Image Processing system has been developed at ITRE. The system is capable of tracking all vehicle, bicyclist, and pedestrian movements in the field of view at high resolutions. Data generated include origin-destination flows, speed profiles, gap and lag acceptance, entry and exit headway distributions, and queue size. From the pedestrian perspective, the system generates micro-scale data on waiting and crossing time distributions, gap and lag acceptance, driver yielding behavior (to pedestrians), and the distribution of the position of yielding vehicles at the crosswalk. This study will duplicate the effort at signalized intersection approaches located in Idaho.

Low-Cost Improvements for Recurring Freeway Bottlenecks
N. Rouphail and Richard Dowling (Dowling and Associates)
NCHRP 3-83, through Dowling and Associates
12/05 to 01/07
Low-cost geometric and operational improvements can mitigate the effects of a bottleneck. The benefits may not be as extensive or long-lasting as those of a major reconstruction project, but improved system performance can easily justify its use. Improving a bottleneck may result in the congestion moving downstream to a new bottleneck that was not apparent previously, greatly reducing the expected benefits. Analysis of the entire network is necessary to accurately estimate the benefits and effects of different improvements. The objective of this project is to develop a technical guide for identifying and treating existing and future recurring freeway bottlenecks.

Crossing Solutions At Roundabouts and Channelized Turn Lanes for Pedestrians With Visions Disabilities
Ron Hughes (ITRE) and Nagui Rouphail
UNC-CH, NCHRP 3-78
01/04 to 01/09
The objective of this research is to produce recommendations for geometric designs, traffic control devices, and other treatments that enable pedestrians who are visually impaired to cross roundabouts and channelized turn lanes (CTL's) independently and safely. These recommendations should be suitable for inclusion in transportation-industry practice and policies, including the AASHTO Policy on Geometric Design of Highways and Streets and the FHWA Manual on Uniform Traffic Control Devices. Consideration should be given to the impact of the recommendations on all users of roundabout intersections, including occupants of passenger car and trucks, pedestrians (including pedestrians with vision impairments), and bicycles.

Regional Development, Population Trend and Technology Change Impacts on Future Air Pollution Emissions
N.M. Rouphail and H.C. Frey
UNC-CH, EPA
11/04 to 11/07
The research tests the hypothesis that smart-growth development patterns can significantly influence the quantity and location of direct and indirect emissions from mobile sources. The patterns of interest include the type of development and its location. We will develop a general method for exploring the leverage that smart-growth development patterns have on the spatial pattern and quantity of emissions from mobile sources. We will explore scenarios and chart the envelope of the effectiveness of smart growth as a means for reducing emissions. We will determine whether substantial emissions reductions are feasible with forecasts of the market penetration of smart growth.

Multi-Modal Arterial Level of Service
Richard Dowling and N.M. Rouphail
NCHRP 3-70 subcontract to ITRE
03/03 to 06/07
The objective of this research is to develop and test a framework and enhanced methods for determining levels of service for automobile, transit, bicycle, and pedestrian modes on urban streets, in particular with respect to the interaction among the modes. Two phases of the research have been funded.

North Carolina Truck Network Model
J.R. Stone and B. Mei
NC Department of Transportation
07/05 to 12/06
Truck traffic is a primary determinant of design and maintenance of bridge structures, pavements, and highways. Proximity to good truck routes enhances community development and economic vitality. Therefore, accurate estimates of future truck traffic are vitally important to the NC Department of Transportation and the state economy. This project will develop a statewide truck network model to estimate future truck traffic and the network effects of alternative highway improvement policies.

Multi-Year Travel Model Research
J.R. Stone, B. Mei (ITRE), A. Khattak (UNC)
NC Department of Transportation
07/04 to 06/07
NC Department of Transportation (NCDOT) staff members develop transportation plans for all NC communities. To simplify, streamline, and standardize the travel demand modeling process, we will develop guidelines for best practices for developing travel demand models and sub-models. In addition, we will develop recommendations for sources of data, and we will undertake various kinds of validations of forecasts. These products and associated tools will help assure that NCDOT staff members efficiently use their time and resources to carry out their statewide transportation planning and modeling mission.

EPA Truck Anti-Idling Demonstration Project
A. Tazewell (NC Solar Center), H. Christopher Frey, and J.R. Stone
EPA
02/06 to 02/08
The objective is to assess potential environmental benefits of heavy duty diesel freight truck idle reduction technologies installed on trucks in NC. A key goal is to quantify actual grams per gallons emissions with a portable gas analyzer and compare this data with data extrapolated from an on-board data logger and fuel use with and without idle reduction technologies.

Effects of Prolonged Heating on the Asphalt-Aggregate Bond Strength of HMA Containing Liquid
A.A. Tayebali and D. Knappe
NC Department of Transportation
07/06 to 06/08
The objectives of this research are to determine the effect of prolonged heating on (1) asphalt-aggregate bond strength and (2) the moisture sensitivity of asphalt mixtures. In particular, this study will first evaluate the performance of mixtures using the tensile strength ratio test (AASHTO T283), and second, study the effect of additive content and prolonged heating on the surface interaction between asphalt binder and aggregate.

Effectiveness of Traveler Information Tools
B.M. Williams and N. Rouphail
NC Department of Transportation
07/05 to 06/07
The NC Department of Transportation (NCDOT) has been deploying Intelligent Transportation System (ITS) devices, including Advanced Traveler Information Systems (ATIS), throughout the state over the past decade. However, owing to the limited knowledge about ATIS technology effectiveness and associated benefits and costs, we propose to assess whether they are (1) effective, (2) accessible to a wide range of travelers and (3) accepted/used by travelers. This study will allow the NCDOT to make more informed decisions about ITS deployment. We will also determine if there are other/new ATIS technologies that the NCDOT should consider for deployment.

Career: System-wide Traffic Condition Monitoring and State Estimation for Intelligent Transportation Systems
B.M. Williams
National Science Foundation
06/02 to 05/07
This five-year research and education program involves the teaching and application of rigorous and robust statistical modeling techniques to the process of assessing and predicting traffic stream states based on remotely sensed traffic data in advanced traffic management systems. Research results will include improved real-time traveler information, more rapid incident detection and response, and enhanced information support for dynamic transportation system management.

Environmental Implications of Current Domestic Trends in Goods Movement
B.M. Williams and G.F. List
Center for Transportation and the Environment
(Prime Sponsor: US Department of Transportation)
03/05 to 03/07
This research project will assess the environmental implications of global and domestic freight trends with a primary focus on congested gateways, such as deep water ports and border crossings. The project results will include policy recommendations for addressing freight-related environmental issues in a manner that will "ensure goods move efficiently and effectively through our ports and freight hubs while protecting the environment."

Best Practices Guidebook for Greenhouse Gas Reductions in Freight Transportation
B. Williams and H.C. Frey
US Department of Transportation via Center for Transportation and the Environment
03/05 to 03/07
This research project involves a comprehensive scan of the freight sector, including public and private sector players, to catalog the practices and programs that are being used to reduce greenhouse gas emissions in the goods movement. All transportation modes will be included. The final research product will be a best practices guidebook to be published and disseminated by the US Department of Transportation.