Transportation Systems and Materials

Research Project Abstracts: 2004 - 2005

In-Vehicle Energy and Emissions Information System (IVEEIS)
H.C. Frey and N.M. Rouphail
National Science Foundation
03/03 to 12/05
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.

Operational Evaluation of Emissions and Fuel Cell Use of B20 versus Diesel Vehicles
H.C. Frey and N.M. Rouphail
N.C. Department of Transportation
10/03 to 09/04
This project involves design and implementation of a field data collection study on diesel vehicles to measure second-by-second emissions of NOx, Particulate Matter, CO, and CO2, fuel use, engine data, and vehicle activity (e.g., speed, location) data using an on-board portable instrument. Benchmark modal emission rates will enable comparison of B20 and conventional diesel fuel, estimation of emission factors, and identification of opportunities to reduce emissions and fuel use through improved vehicle operation. Strategic recommendations will be made regarding biodiesel fuel, air quality management, energy management, and improved operation.

An Evaluation of the Safety Effects of Speed Enforcement Camera
J.E. Hummer
NC Governor's Highway Safety Program
10/03 to 09/05
Speed enforcement cameras that automatically record the license number of a vehicle exceeding a limit are one technologically-feasible way to address speed-related safety problems. The North Carolina Legislature has recently given the City of Charlotte approval to use speed enforcement cameras. The purpose of this project is to help evaluate those installations, to see whether other highway agencies could expect collision reductions should they also use speed enforcement cameras. The project will consist of a literature review, an examination of public opinion through focus groups, and before-and-after collision and speed studies at camera sites.

Railroad Crossing Wayside Horn Evaluation
J.E. Hummer
N.C. Department of Transportation
07/02 to 06/06
The noise from train horns is irritating to people living and working along railroad tracks, and causes opposition when new train service is proposed. However, the train horn is also an essential safety device for motorists at grade crossings. A device called a wayside horn has been marketed in the U.S. that promises to reduce that irritation by mounting the horn at the road crossing and directing the sound at motorists. The purpose of this project is to evaluate the device at a crossing in North Carolina by means of driver surveys, resident surveys, and roadway operational measures.

Expanding the Use of Photo Enforcement to Enhance Traffic Safety in North Carolina, Year 2
J.E. Hummer
NC Governor's Highway Safety Program
10/02 to 09/04
One of the primary causes of crashes at intersections across the state of North Carolina and across the United States is when a vehicle enters an intersection during the red interval. Red light camera photographic enforcement has been used in the United States since 1992, and has been used in North Carolina in the past five years, to try to address those crashes. However, to this point there has not been valid research completed to prove their safety benefits. In this project, we will conduct a before-and-after test with comparison sites in Raleigh, NC to examine those safety benefits.

Developing Planning Level Crash Prediction Models
J.E. Hummer
University of Tennessee
10/03 to 08/04
The main objective of the project is to develop models that predict the future number of reported crashes on one or more major types of roadway using only average daily traffic and other simple inputs typically available during long-range transportation planning. Planners can then use the models to help prioritize future roadway improvement projects, when typically now only very crude collision rates are used in an ad hoc way for such purposes.

Evaluation of Safety, Design, and Operation of Shared Use Paths
J.E. Hummer, N.M. Rouphail, and J.S. Milazzo II
Federal Highway Administration
10/00 to 05/05
Off-street paths are becoming common in the U.S. To provide better facilities, designers need guidance on the quality of service offered by paths of different widths and configurations handling different volumes of users. The purpose of the project is to develop and validate a quantitative procedure for estimating that quality of service. This research builds upon a methodology recommended by the research team in a previous project for the Federal Highway Administration. A major work element in this research is the collection of operational data on paths across the U.S. The research team will also collect path user perceptions.

Reasonable Speeds on Improved Curb and Gutter Facilities
J.E. Hummer and B.M. Williams
North Carolina Department of Transportation
07/03 to 05/05
Agencies often construct vertical curbs on new multilane highways which usually necessitates 45 mph speed limits. This may create an enforcement problem, as drivers do not perceive danger from the curbs. The purpose of this research is to show agencies how to avoid this scenario by answering two key questions. First, do vertical curves next to high-speed lanes really cause more frequent and severe collisions than other cross-section choices? Second, if vertical curbs are more dangerous, is a lower speed limit the best way to alert the public to this danger or are there other treatments?

Tensile Strength - A Design and Evaluation Tool for Superpave Mixtures
N.P.Khosla
NCDOT/FHWA
07/04 to 06/06
Tensile strength plays and important role in the performance of an 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
NCDOT/FHWA
07/04 to 06/06
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.

Implementation Plan for the New Mechanistic-Empirical Pavement Design Guide
Y.R. Kim
N.C. Department of Transportation
05/05 to 06/06
The goal of the research project is to develop an implementation plan for the Guide. This goal will be attained by accomplishing the following objectives:

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: (1) to 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) to incorporate the VEPCD model into the finite element code (VEPCD-FEP++); and (3) to calibrate the VEPCD-FEP++ using the pavement performance data obtained from the FHWA ALF testing.

Quantifying the Benefits of Improved Rolling of Chip Seals
Y.R. Kim
N.C. 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 NCDOT HWY 2003-09 project, Optimizing Gradations for Surface Treatments. The experimental program involves both laboratory and field experiments.

Typical Dynamic Moduli for North Carolina Asphalt Concrete Mixes
Y.R. Kim
N.C. Department of Transportation
07/02 to 06/04
The dynamic modulus of asphalt concrete will be used as the key parameter in the 2002 AASHTO Design Guide as well as in the Superpave simple performance test protocol that complements the volumetric mix design. The release of the new AASHTO pavement design guide in 2002 makes it urgent to obtain dynamic moduli values of typical asphalt mixes used in North Carolina. The objective of this proposal is to develop a database of dynamic moduli values and their variability for asphalt mixes used in North Carolina. In addition to dynamic modulus testing of the representative mixes, surrogate methods will be evaluated, including the impact resonance method and Witczak's predictive equation.

Determination of Dynamic Moduli for Typical North Carolina Asphalt Mixtures Modified with Lime
Y.R. Kim
Chemical Lime Company
05/03 to 05/04
The objective of this proposal is to develop a dynamic modulus database for typical asphalt mixtures modified with lime in parallel with the NCDOT database. Only the axial compression test method will be used in this project with the anticipation of adding the indirect tension test method later when funds are avaiable. Also, the applicability of Witczak's predictive equation to lime-modified mixtures will be evaluated. The dynamic modulus database to be developed from this project will yield necessary information for the NCDOT to design asphalt pavements with lime-modified mixtures using the new AASHTO pavement design guide.

Optimizing Gradations for Surface Treatments
Y.R. Kim
N.C. Department of Transportation
07/03 to 06/05
Due to the ongoing commitment to pavement preservation and the growing number of miles of low volume roads, the use of surface treatments has increased substantially in recent years and is likely to continue to rise in the future. The primary objective of this research project is to evaluate the current mixture characteristics of surface treatments used in North Carolina and recommend modifications to the current specifications, particularly those related to aggregate gradations, if needed. In addition, the effects of different mixture characteristics on performance are identified and incorporated in mix design guidelines.

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.
06/05 to 08/08
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 Corp.
09/04 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++); (5) calibration of the VECPD-FEP++ using the data measured from the KHC Test Road pavements; (6) development of transfer functions for the 33 asphalt pavements in the Test Road; and (7) development of a user-friendly graphic interface for pre- and post-processing of the VEPCD-FEP++.

Investigation of the Causes for Cracking on Longitudinal Joints in Glassgrid Reinforced Asphalt Pavements
Y.R. Kim and M.N. Guddati
Saint-Gobain Technical Fabrics
06/04 to 09/04
The primary objective of the proposed research is to investigate the effects of vibratory compaction and grid opening size on the density of asphalt pavement over the GlasGrid longitudinal joint. Two grid materials, GlasGrid 8501 with half inch openings and GlasGrid 8511 with one inch openings, are investigated in this study.

Characterization of ALF Mixtures Using the Viscoelastoplastic Continuum Damage Model
Y.R. Kim and M.N. Guddati
FHWA
08/03 to 08/05
The primary objectives of the proposed research are: (1) to verify the time-temperature superposition principle in damaged states for various asphalt mixtures used in the current ALF study; (2) to characterize the ALF mixtures using the viscoelastoplastic continuum damage model; and (3) to predict the performance of various ALF pavements using finite element analysis and the VEPCD model.

Designing an Efficient Nighttime Sign Inspection Program that Ensures Motorist Safety
W.J. Rasdorf and J.E. Hummer
N.C. Department of Transportation
07/04 to 06/06
During a previous project for NCDOT, we developed a prototype simulation tool to quantitatively evaluate the effectiveness of different sign inspection and replacement scenarios. The purpose of this project is to improve the prototype and allow agencies to use the simulation with confidence. In particular, we will incorporate the best possible sign deterioration functions into the simulation, expand the types of signs analyzed, and add performance data from NCDOT sign inspectors. With these additions, the simulation should be capable of saving agencies many needless sign replacements while insuring that signs meet minimum visibility standards.

Crossing Solutions At Roundabouts and Channelized Turn Lanes for Pedestrians With Visions Disabilities
Nagui Rouphail
UNC-CH, NCHRP 3-78
02//05 to 01/08
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
09/04 to 08/07
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.

Evaluation and Application of Pedestrian Modeling Capabilities Using Computer Simulation
N.M. Rouphail
UNC-CH and National Institutes of Health
01/03 to 05/05
Modern roundabouts are increasingly being used in the United States in light of their good capacity and safety performances compared to conventional signalized or un-signalized intersections. Many recent applications show that by enhancing priority control and speed enforcement, modern roundabouts can increase vehicle capacity as well as reduce accident rates. Previous research on modern roundabouts was mainly concerned with vehicle performance. Since roundabouts in urban areas have the potential for servicing large volume of pedestrians, the evaluation of their overall performance should also include analysis of pedestrian crossing capacity, delay and safety issues.

North Carolina Forecasts for Truck Traffic
J.R. Stone
N.C. Department of Transportation
07/0 to 12/04
Estimates of truck traffic are critical parameters in designing and maintaining highway pavement and structures. National databases suggest that trucks are becoming an increasingly larger proportion of traffic. Anecdotal reports suggest that North Carolina truck traffic is increasing in excess of national averages. Consequently designers apply generous adjustments for forecast truck traffic. However, over estimates lead to over design and unnecessary construction cost. This project helps resolve these issues through improved data collection, display and analysis techniques.

Multi-Year Travel Model Research
J.R. Stone, L.F. Huntsinger, (ITRE), and A. Khattak (UNC)
N.C. Department of Transportation
07/04 to 06/07
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.

Benefit-Cost Analysis Software for Transportation Planning
J.R. Stone and R.S. Foyle (ITRE)
N.C. Department of Transportation
07/04 to 06/05
Evaluating transportation projects for feasibility purposes can be a time consuming and difficult process. Over time and a variety of projects, the process can also become very inconsistent as different engineers apply various parameters. We will provide the North Carolina Department of Transportation a decision-support tool and software that will provide a consistent methodology for evaluating costs and benefits for NC transportation projects and amendments to programmed projects.

Use of Lime as Anti-strip Additive for Mitigating Moisture Susceptibility of Asphalt Mixes Containing Baghouse Fines
A.A. Tayebali
N.C. Department of Transportation
07/04 to 06/05
The objective of this research project is to conduct a laboratory study of moisture sensitivity of asphalt mixes containing controlled percentages of Boone and Enka baghouse fines in the amount of 0, and 4-percent. In this study, lime will be used as an anti-strip agent to determine its effectiveness in mitigating moisture damage. The results of this study will complete, and support the outcome of the previous NCDOT studies that investigated mitigation of moisture susceptibility of mixes containing baghouse fines with organic anti-strip additives. The recommendations based on results of this study should enable NCDOT to formulate specifications with regards to the use of baghouse fines in NCDOT mixes.

Performance Grading (PG) of Iceland Bitumen B-180 and B-85
A.A. Tayebali
Iceland Public Roads Administration
05/04 to 08/04
The objective of this study is to characterize Asphalts (bitumen) cements B-180 and B-85 used in Iceland, using the Superpave "Performance Grading" methodology.

Quantifying Anti-Strip Additive in Asphalt (Binders and Mixes)
A.A. Tayebali and D.R.U. Knappe
N.C. Department of Transportation
07/03 to 12/04
The objective of this research will be to develop a reliable and repeatable laboratory and/or field test procedure to determine the amount of organic anti-strip agent in asphalt binders and asphalt mixtures. In this investigation, two test methodologies will be investigated. These include 1) a colorimetric test, and 2) a litmus test using the StripScan device. Both methodologies utilize a spectrophotometer for the analysis of anti-strip additive concentration in asphalt mixes.

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.

I-40 Reversal Operational Traffic Analysis
B.M. Williams (PI) & S.S. Meinhold (Co-PI), N.M. Rouphail, Project Advisor, and J.E. Hummer, Project Advisor
N.C. Department of Transportation
07/03 to 06/05
The NCDOT developed a lane reversal plan for using the eastbound lanes of I-40 for additional hurricane evacuation capacity. Traffic operation under evacuation conditions, especially operation of reversed lanes, are not well understood. This project involved investigational research of reverse lane operation and modeling and analysis of the I-40 lane reversal plan. Results will include recommendations for improving the current plan.