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- 100-car reanalysis: summary of primary and secondary driver characteristicsMcClafferty, Julie A.; Hankey, Jonathan M. (National Surface Transportation Safety Center for Excellence, 2010-08-27)This project's goal was to build a complete trip file inventory for the 100-Car data set... Data points collected for each file include Driver ID (with new IDs created as new secondary drivers were found), Ambient Lighting, Driver Seatbelt Usage, and an assessment of video operations/quality. --executive summary.
- 30 Years – 20 State DOTs: Trends in Pavement Management observed through real world Implementation at the State DOT LevelZavitski, Jeffrey L.; Piane, Robert R. (2013-06-04)Since the first International Conference on Managing Pavement Assets 30 years ago in 1985, there has been continuous enhancement and evolution of pavement management system (PMS) technology to produce more effective recommendations coming out of an agency's PMS. Improvements in data collection, performance measures, deterioration modeling, dynamic segmentation, treatment algorithms, triggering mechanisms and optimization technologies have led to significant improvements in PMS strategy recommendations as well as the acceptance of those recommendations in both centralized and de-centralized State Departments of Transportation (DOT). Significant efforts have also been invested in methodologies and technologies to integrate PMS into an overall asset management system (AMS) at the State DOT level utilizing cross asset optimization technologies. This paper will examine the evolution of pavement management from the desktop environment to today's enterprise pavement management systems within 20 State DOTs that use a common software platform and present significant changes in pavement management methodologies that lead to increased use and acceptance of the PMS recommendations and adoption within the agency. It will also examine current trends that will impact the systems of tomorrow including integration with other decision making tools, capturing field data, and alternative approaches to optimization.
- 3D Pavement Surface Macrotexture: Measurements And Friction RelationshipsShalaby, Ahmed; El Gendy, Amin (2012)Pavement macrotexture is typically reported as mean profile depth over a standard base length. Recently, a new measurement method based on photometric stereo system was introduced. The method requires a minimum of three images of the surface that are illuminated from different directions and isolated from ambient lighting. The variation in intensity of the lighting is used to recover the 3D pavement surface. This paper discusses applications of the photometric stereo system as a new non-contact texture measurement method. The 3D pavement surface is analyzed in space and frequency domains. In frequency domain, the power spectrum energy which reflects the wavelength content of the surface model is introduced as an indicator of surface evenness. The relationship between friction and the 3D texture indicators is examined. The research shows that the texture indicators computed from the recovered surface provide new substantial information on the quality and condition of the riding surface.
- 4U Lighting – Cooperative HeadlightingPalmer, Matthew; Tsuda, Hiroshi; Williams, Brian M.; Gibbons, Ronald B. (National Surface Transportation Safety Center for Excellence, 2019-10-31)The purpose of this project was to evaluate the effectiveness of an alternative cooperative headlighting method, dubbed 4U Lighting. A human-subjects study was conducted in which 12 participants 65 or older observed pedestrians under different lighting configurations and identified the moment when they were sure they could see a pedestrian. The participants drove a vehicle towards a static vehicle in the opposite lane around which the pedestrians were located. The distance at which participants could detect the pedestrian, termed the detection distance, was compared across lighting conditions and served as the measure of improvement in driver visual performance (visibility). Commercial connected vehicle hardware and protocols were used to communicate position between the two vehicles and to trigger the operation of the custom lighting control system. The system operated as expected and the data showed benefits to driver visual performance.
- 9th International Conference on Managing Pavement AssetsVirginia Tech Transportation Institute (2015-05)This conference program lists the events that took place during the 9th International Conference on Managing Pavement Assets (ICMPA9), which was held from May 18-21, 2015 in Alexandria, VA. The conference brought together pavement design and management engineers, companies specialized in providing pavement management services and data collection, researchers and specialists on asset/pavement management, general pavement/road engineers, planners dealing with the development of public works programs, and academics specializing in pavement design, analysis and management. The conference aimed to define the requirements for the "next generation" of pavement management tools need and to that effect it builds upon the following theme: "moving pavement management beyond the short-term: embracing innovation and addressing sustainability, accountability, and improved performance." ICMPA9 was organized by the Virginia Tech Transportation Institute, the Federal Highway Administration, the Virginia Department of Transportation, the American Association of State Highway and Transportation Officials (AASHTO), the Transportation Research Board, and the World Road Association.
- About The Reproducibility Of Texture Profiles And The Problem Of SpikesGoubert, Luc; Bergiers, Anneleen (2012)The ISO working group ISO/TC43/SC1/WG39 has recently been worrying about the quality of texture profiles, measured with laser profilometers. It appears that the quality has not improved in recent years, rather on the contrary: in spite of the technological progress it appears to decrease! The WG is especially concerned of the presence of invalid positive spikes in some profiles which might dramatically affect the Mean Profile Depths (MPD)  and to some extent the texture spectra calculated with those spectra, if one does not properly deal with these erroneous measurement points prior to calculating the MPD or spectrum. In this paper the results of an international round robin test with static laser profilometer devices on two epoxy moulds of dense asphalt concrete road surfaces are shown, indicating the reproducibility of this kind of devices for the wavelength range from 2,5 mm up to 125 mm. A new procedure to deal with the spike problem is presented. The aim is to remove the spikes without affecting significantly the valid part of the spectra. The effect on MPD and spectra will be shown for some typical cases. The method, based on the detection of steep jumps in the profile, appears to work.
- About The Rolling Resistance Trailer And Parameters Influencing Rolling ResistanceBergiers, Anneleen; Goubert, Luc; Vuye, Cedric (2012)The issue of global warming by an excessive amount of carbon dioxide (CO2) in the atmosphere is a hot topic and the consequences for man and environment become more and more clear. Road transportation plays a significant role in CO2 emission and unlike other sectors, its emission has even increased the last years. To stop this trend, different measures may be taken: e.g. tackling traffic congestion, lowering the consumption of the vehicles… Many other parameters influence CO2 emission by transportation: e.g. tyre, vehicle and road characteristics… In this paper the influence of the road surface is investigated with a “quarter-car” trailer, suitable to measure rolling resistance with a car tyre on different road surface types. Texture measurements with a laser profilometer are performed to examine the correlation between rolling resistance and texture. The impacts of different parameters are investigated: repeatability over short and long time, speed, wind, tyre inflation pressure, tyre load, tyre type … Some rough coast down measurements are performed to compare with the trailer method. By gaining more knowledge about this topic, more environmental friendly and sustainable road infrastructure may be developed and implemented. This is expected to be an important tool for policy makers in their fight against CO2 emission.
- Accelerated Testing and Instrumentation: A Canadian Case StudyTighe, Susan L. (2015-06-04)The primary objective of this paper is to describe how the CPATT Test Track is used to advance Canadian pavement engineering practices through the investigation of the impact of axle loads and environment on flexible and rigid pavement structures. It also discusses how the Track is used as an educational tool for both undergraduate and graduate students. Since construction, over 1,000 undergraduate and graduates have not only visited the Test Track, but have used the data from the Test Track for course assignments and other research. It has been a valuable and strategic asset for both research and education.
- Access Control Design on Highway InterchangesRakha, Hesham A.; Flintsch, Alejandra Medina; Arafeh, Mazen; Abdel-Salam, Abdel-Salam Gomaa; Dua, Dhruv; Abbas, Montasir M. (Virginia Center for Transportation Innovation and Research, 2008-01-01)The adequate spacing and design of access to crossroads in the vicinity of freeway ramps are critical to the safety and traffic operations of both the freeway and the crossroad. The research presented in this report develops a methodology to evaluate the safety impact of different access road spacing standards. The results clearly demonstrate the shortcomings of the AASHTO standards and the benefits of enhancing them. The models developed as part of this research were used to compute the crash rate associated with alternative section spacing. The study demonstrates that the models satisfied the statistical requirements and provide reasonable crash estimates. The results demonstrate an eight-fold decrease in the crash rate when the access road spacing increases from 0 to 300 m. An increase in the minimum spacing from 90 m (300 ft) to 180 m (600 ft) results in a 50 percent reduction in the crash rate. The models were used to develop lookup tables that quantify the impact of access road spacing on the expected number of crashes per unit distance. The tables demonstrate a decrease in the crash rate as the access road spacing increases. An attempt was made to quantify the safety cost of alternative access road spacing using a weighted average crash cost. The weighted average crash cost was computed considering that 0.6, 34.8, and 64.6 percent of the crashes were fatal, injury, and property damage crashes, respectively. These proportions were generated from the field observed data. The cost of each of these crashes was provided by VDOT as $3,760,000, $48,200, and $6,500 for fatal, injury, and property damage crashes, respectively. This provided an average weighted crash cost of $43,533. This average cost was multiplied by the number of crashes per mile to compute the cost associated with different access spacing scenarios. These costs can assist policy makers in quantifying the trade-offs of different access management regulations.
- Achieving High Correlations of Inertial Profilers with Reference Profilers at the Smart Roadde León Izeppi, Edgar; Toom, Paul (2014-09-16)
- Active and Adaptive Roadway Delineation SystemsWilliams, Brian M.; Gibbons, Ronald B.; Flintsch, Alejandra Medina (National Surface Transportation Safety Center for Excellence, 2017-10-13)Heavy fog presents a significant safety hazard to drivers by reducing their ability to see the roadway and other vehicles. Even so, drivers often fail to adjust their speed to account for the reduced visibility, resulting in stopping distances that exceed visibility distance. Active delineators, or in-pavement light emitting diode (LED) markers, are an emerging technology which can be used to assist drivers in traveling through fog-prone areas by marking road or lane boundaries. However, there is a lack of research indicating how the presence of active delineators might also affect a driver’s behavior. This study sought to examine how the presence of active delineators in fog might affect drivers’ speed. Three lighting patterns and two brightness levels were tested. In daytime conditions, the delineators had no effect on speed. During nighttime conditions, participants often drove faster when the active delineators were present. Participants felt that the active delineators were helpful for navigating through the fog in both daytime and nighttime conditions, but preferred the higher brightness settings in the daytime.
- Adaptive Control of the Atmospheric Plasma Spray Process for Functionally Graded Thermal Barrier CoatingsGuduri, Balachandar; Batra, Romesh C. (Hindawi, 2022-11-23)Functionally graded coatings (FGCs) have a material composition continuously varying through the thickness but uniform in the surface parallel to the coated substrate. When used as a thermal barrier on a metallic substrate, the coating composition varies from an almost pure metal near the substrate to a pure ceramic adjacent to the outer surface exposed to a hot environment. Challenging issues in producing high quality FGCs in the presence of external disturbances with an atmospheric plasma spray process (APSP) include controlling the mean temperature, the mean axial velocity, and the positions of the constituent material particles when they arrive at the substrate to be coated. The unavoidable disturbances include fluctuations in the arc voltage and clogging of the powder in the delivery system. For a two-constituent coating, this work proposes using three modified robust model reference adaptive controllers based on the σ-modified laws and low frequency learning. One controller adjusts the current and flow rates of argon and hydrogen into the torch. The other two controllers adjust the distance of the two powder injector ports from the plasma jet axis and the average injection velocity of each powder. It is shown through numerical experiments that the three controllers implemented in an APSP consistently produce high-quality FGCs.
- Adaptive Traffic Signal Control: Game-Theoretic Decentralized vs. Centralized Perimeter ControlElouni, Maha; Abdelghaffar, Hossam M.; Rakha, Hesham A. (MDPI, 2021-01-03)This paper compares the operation of a decentralized Nash bargaining traffic signal controller (DNB) to the operation of state-of-the-art adaptive and gating traffic signal control. Perimeter control (gating), based on the network fundamental diagram (NFD), was applied on the borders of a protected urban network (PN) to prevent and/or disperse traffic congestion. The operation of gating control and local adaptive controllers was compared to the operation of the developed DNB traffic signal controller. The controllers were implemented and their performance assessed on a grid network in the INTEGRATION microscopic simulation software. The results show that the DNB controller, although not designed to solve perimeter control problems, successfully prevents congestion from building inside the PN and improves the performance of the entire network. Specifically, the DNB controller outperforms both gating and non-gating controllers, with reductions in the average travel time ranging between 21% and 41%, total delay ranging between 40% and 55%, and emission levels/fuel consumption ranging between 12% and 20%. The results demonstrate statistically significant benefits of using the developed DNB controller over other state-of-the-art centralized and decentralized gating/adaptive traffic signal controllers.
- Addressing Uncertainties of Performance Modelling with Stochastic Information Packages – Incorporating Uncertainty in Performance and Budget ForecastsKadar, Peter; Martin, Tim; Baran, Michelle; Sen, Ranita (2015-05-19)A large volume of data is collected world-wide to feed pavement management systems (PMS). The data is typically condensed to characterize pavement sections or smaller sub-networks by using statistical measures mostly averages. In this process valuable information is lost, thus increasing the likelihood of providing inaccurate or in some cases misleading answers. The pitfalls of using averages can be avoided by utilizing the full data set and treating each data set as an entity or stochastic information packet (SIP). Modeling with SIPs means that the input as well the output of the modeling is a distribution as opposed to the singular outcome of deterministic models. The resulting distribution allows determination of the probability of the outcome besides its predicted value. Budget and condition forecasts therefore may include not only the future condition and budget requirements, but their reliability and consequently the level of associated risks. Managing agencies and contractors may choose the budget scenario best reflecting their level of risk acceptance or tolerance. Modeling with SIPs builds on deterministic models by expanding their outcomes into full distributions. Working with arrays (SIPs) requires using a novel approach that is described and illustrated in the paper.
- Advanced Automated Detection Analysis and Classification of Cracks in PavementScott, Dennis (2014-09)
- Advancing Pavement Surface Evaluation to Support Engineering and Investment DecisionsDaleiden, Jerome (2014-09)
- Advancing Pavement Surface Evaluation to Support Engineering and Investment DecisionsDaleiden, Jerome; Burchett, Thomas; Mergenmeier, Andy (2015-05-01)The American Association of State Highway and Transportation Officials (AASHTO's) Pavement Rutting and Cracking Quantification Expert Task Group (ETG) was formed in 2006 with Federal Highway Administration (FHWA) funding to provide program guidance and assistance in development and enhancement of standards for pavement rutting and asphalt pavement surface cracking. The ETG was formed with subject matter experts to represent AASHTO, FHWA, the American Society for Testing and Materials (ASTM) Committee E-17 on Vehicle-Pavement Systems, Transportation Research Board (TRB), the Long Term Pavement Performance (LTPP) Program, academia, and industry. Revised data collection and analysis protocols have been produced and evaluations are being initiated to identify how best to continue the development process.