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The objectives of this project are to: (1) Establish a procedure to identify the optimum antistrip additive content for a given asphalt mixture and antistrip additive combination; (2) Evaluate the moisture damage resistance of plant-produced asphalt mixtures to establish a preliminary protocol for quality assurance and control; and (3) Develop an objective means to quantify emulsion- aggregate compatibility in lieu of the visual assessment procedure currently specified in NCDOT A-24 procedure. Laboratory- mixed, laboratory compacted mixtures were used to establish an antistrip dosage selection procedure for Boil test results coupled with Asphalt Compatibility Tester (ACT) color measurements.

NC-26-7003, This report reviews the state of advanced public transportation systems (APTS) technology. It contains information on software and hardware, including product characteristics, costs and vendors. The report also references an internet site which summarizes the report and contains information on APTS technologies.

This research effort is part of a collaborative research project between the North Carolina Department of Transportation (NCDOT) and North Carolina State University’s (NCSU’s) Institute for Transportation Research and Education. As North Carolina confronts increasing transportation budget deficits, reliable revenue generating mechanisms will become invaluable to preserve the state’s transportation infrastructure. Understanding public perception of current and potential transportation funding mechanisms will be important for NCDOT and other decision-makers. The primary objective of this research is to not only summarize North Carolinians’ perceptions about transportation funding mechanisms, but to also explore their determinants and potential implications. This research builds from prior findings in 2019 and 2020 and seeks to further expand understanding of public opinions about transportation. Through the continuation of a longitudinal survey and the addition of twelve focus groups, several findings emerged regarding North Carolina residents’ perceptions of transportation funding and electric vehicles. Overall, respondents support increasing transportation funding and feel strongly that funding should be increased. Respondents preferred that transportation funding be supported through a general increase in the state sales tax, however, there is some support for increase in annual registration fees and the introduction of a new mileage-based usage fee. Regarding transportation funding, there are few major differences between demographic groups. However, when it comes to perceptions of electric vehicles, there are some notable differences between political ideological groups, age groups, and ethnic groups.

DTFH6116D00040, This research project explores and evaluates the effectiveness of different static late merge signing for use on arterials. The research team collected data through a laboratory and a field study. The laboratory study assessed the comprehension of the different sign alternatives and determined which sign series to evaluate in the field. The field study evaluated a single sign series at 12 different sites across 3 States to evaluate driver behavior in response to the signs.

The objectives of this project are to: 1) develop recommendations for extender and recycling agent product approval and dosage selection; and 2) identify appropriate aging procedure(s) to simulate long-term oxidative aging coupled with test methods and parameters to characterize the cracking resistance of asphalt binders. Three NCDOT approved surface asphalt mixtures were evaluated in this study, including a reclaimed asphalt pavement (RAP) mixture, recycled asphalt shingle (RAS) mixture, and RAP/RAS mixture. Three extenders and two recycling agents (RAs) were evaluated. The extenders were blended with PG 58-28 virgin binder whereas the RAs were blended with PG 64-22 virgin binder. Blends of recycled binder, virgin binder, and a RA or extender were prepared that achieved similar high-temperature AASHTO M 320 performance-graded properties to virgin PG 64- 22 binders in North Carolina.

NCDOT Project 2020-30, This report summarizes the findings of a research project aimed at assessing the accuracy of both analytical and microsimulation tools in describing the operational performance of a variety of intersection and interchange types under North Carolina conditions. The three tools evaluated in this study were SYNCHRO10, SIDRA9 and Trans Modeler5. In addition, some basic comparisons with the FHWA CAP-X sketch planning tool was carried out for some sites. The original, Pre-Covid scope of work was to cover ten congested interrupted flow facilities in the field. The revised scope reduced the field effort to six sites, including an isolated and coordinated signalized intersection; a single lane roundabout; a traditional diamond interchange; an offset intersection and a continuous flow intersection with an additional two alternative intersection (AI) sites (Diverging Diamond Interchange and a Reduced Conflict Intersection) processed via a sensitivity analysis to variations in demand volumes, capacity and control conditions.

69A3551747104, Continuous Flow Intersections (CFIs), also known as Displaced Left-Turn intersections (DLTs) have grown in popularity primarily due to the reduced number of signal phases for vehicles. However, due to its large footprint and unconventional displaced left-turn movement, pedestrians and bicycles experience unique mobility challenges at this type of intersection.

NCDOT RP 2019-28, Safety for all road users is a key concern as Connected and Autonomous Vehicle technologies develop and reach the testing phase. One key concern is the change to two-way communication that often occurs in traditional pedestrian-vehicle interaction. This project focused on three key aspects to this issue. First, a prototype autonomous shuttle system was expanded to include additional communication features in a lightbar as well as more advanced pedestrian detection systems. Secondly, multiple detection methods were trained and tested using traditional datasets as well as a new dataset including occluded pedestrians. Finally, a survey was conducted to determine how well pedestrians understand specific static or dynamic lightbar patterns as an additional communication tool for CAVs. This project tested multiple pedestrian detection methods and developed improved methods with increased accuracy and reduced latency. The EcoPRT vehicle was able to incorporate the improved detection method, however the training image set included multiple camera perspectives and the method could likely be applied to infrastructure-based detection systems. Additionally, the project developed a body part-based method which detects head, arms and legs of pedestrians in order to improve the overall detection of pedestrians when they are partially occluded. The project also developed a database of occluded pedestrian images which can be used for training or testing other new methods addressing this issue. Finally, the project examined multiple methods for signaling the CAV intent to pedestrians using fixed or moving lightbars. Respondents struggled to correctly identify the message communicated by the lightbar in cases where multiple movements are expected (such as locations with potential turning movements) but identification improved in more constrained environments.

NCDOT RP 2019-30, Integrated Corridor Management (ICM) systems offer the potential to manage both travel demand and network demand in normal and abnormal conditions. Traditionally, ICM is typically applied in an urban setting where multiple transportation modes are readily available. NCDOT has applied ICM principles, but in more rural applications where less modal and network options are likely to exist. NCDOT has deployed ICM on 22 miles of I-85 from MM 10 to 32 near Charlotte with a focus on managing incident-related congestion on the interstate and parallel US-74 arterial. This deployment includes traveler information on Dynamic Message Signs, activatable detour trailblazer signs for individual incidents, and incident-specific signal timing plans for intersections included in the detours. Observations of traffic flow patterns are essential to accurately capture the traffic diverted due to ICM activations. In this project, Bluetooth and Wi-Fi traffic monitoring devices were placed throughout the corridor and used to match trips along the primary and detour routes to establish baseline O-D patterns which can be compared to ICM activations after implementation. This project also adapted an existing sketch-planning NCDOT analysis method used in the project prioritization process to compare estimated delays on primary and detour routes during ICM operation. The inputs for diversion rates and capacity benefits from ICM-specific signal timing can be updated as observations provide better estimates. This project developed a live dashboard integrating data feeds from public and private sources presented in a compact set of maps and graphs. NCDOT performs after action reviews of severe incidents including those in the I-85 ICM deployment, which may use the dashboard to supplement their review. Finally, this project developed an evaluation framework which captures delay, safety, environmental, administrative, and capital impacts of ICM deployment. This analysis framework is recommended for t

NCDOT RP 2019-25, In North Carolina, wrong way driving (WWD) crashes are one of the most severe traffic crashes that often result in a fatality or serious injury since they involve head-on or opposite direction sideswipe crashes at high speeds. To minimize the occurrence of WWD crashes, the North Carolina Turnpike Authority (NCTA), which is a unit of the North Carolina Department of Transportation (NCDOT), deployed a wrong way vehicle detection system along the Monroe Expressway in 2018. The system can automatically detect wrong way vehicles at mainline stations and inform traffic management center operators. This project evaluated the effectiveness of wrong-way traffic control devices installed at the ramp and mainline locations along the Monroe Expressway. A comprehensive literature search was conducted to summarize the state-of-the-practice of WWD crash modeling, detection, and prevention. Real-world traffic data including traffic volume, traffic control devices present, geometry and configuration of interchanges were employed for identifying the relationship between the frequencies of wrong way incidents and facility characteristics. During the study period of approximately 1.5 years of data collection, there were 13 actual WWD events, of which five wrong way movements originated from the roundabout parclo interchanges on the Monroe Expressway. In addition, this project collected statewide data on partial cloverleaf interchanges to assess the risk for wrong way movements. It was found that the partial cloverleaf interchange configuration was associated with the highest number of WWD activities, and factors that affect the risk of WWD mainly include: entrance and exit ramp traffic volume and control type, divided or undivided exit ramp, median cut turn access, left-turn perpendicular turning distance, skew angle, and distance between ramp terminals.

1993 Grant Agreement, Periodic paint removal and re-application is necessary to protect steel girder bridges against corrosion. The paint removal operation for bridge maintenance, however, is hazardous to the workers involved in the process and the natural environment. A particular problem is that certain types of paint used on bridges in the past contain toxic lead. The Robotic Bridge Paint Removal (RBPR) project was initiated under a grant agreement with Federal Highway Administration (FHWA) to study the important factors related to the robotic paint removal process. During the design and development, the unique shape of the bridge beam and the requirement for dust and debris containment caused many problems. These problems, in turn, provided challenges to produce innovative solutions. The robotic paradigm was identified as an especially effective approach for spot cleaning corroded paint on bridge structures. A vision-based computer control architecture was developed that provides the adaptive remote control capabilities for the spot cleaning process. Field tests were conducted throughout the project to evaluate design concepts, identify areas that could be improved, and demonstrate the final working prototype. The results of these demonstrations indicate the application of the robotic paradigm to bridge paint removal has real potential to: 1) improve workers' safety, 2) protect the natural environment during the paint removal process, and 3) minimize the risks to the general public. This project would not have been possible without the close partnership between the North Carolina State University Construction Automation and Robotics Laboratory (CARL) and the North Carolina Department of Transportation (NCDOT). The NCDOT not only loaned many of the key hardware components to the project, they also participated in reconfiguring, upgrading and field testing the new system.

DTFH6194-R-00143, Trenching excavation and pipe-laying are, without a doubt, some of the most dangerous operations in construction. More than 200 people a year, in the United States alone, are killed during these operations. Machines that can reduce or eliminate the exposure of humans to these risks have the highest potentials to change the present situation. This research project was initiated under the contract between the Federal Highway Administration and North Carolina State University in order to develop and evaluate the concept of spatially integrated excavation. The research team had access to three important hardware components: 1) a robotic excavator in the laboratory; 2) a John Deere 690C backhoe excavator equipped with electronic transducers for measuring joint angles; and 3) the ODYSSEY, a laser based spatial positioning system that was integrated with the excavator. The overall goal of this project was to prove the technical feasibility and effectiveness of laser-based spatial position control under real-world conditions. In addition, innovative technologies for the detection of buried metal obstacles and the laying of large pipes without the need for humans in the trench were successfully tested. It is believed that the results of this research project lay the foundation for a dramatic reduction in the number of casualties caused by collapsing trenches, ruptured gas pipes, etc. Additionally, a variety of other benefits can be gained. For example, the automatic establishment of as built drawings, reduction of damaged utilities, increase of productivity due to the quantity of materials to be excavated (to meet Occupational Safety and Health Administration requirements), and finally, the reduction of errors.

A new field monitoring approach in the form of metallic capsules is developed to evaluate Benzene and PCE diffusion through concrete pipe gaskets. The capsules are developed and tested with three gasket materials: Neoprene, Buna-N, and Viton. To validate the monitoring approach and develop field retrieval protocol, capsules were deployed in three contaminated sites: (i) Nash county maintenance depot in Nashville, NC (gasoline contaminated site), (ii) A maintenance facility yard in Newton, NC (gasoline contaminated site), and (iii) Triangle Laundromat in Durham, NC (chlorinated solvent contaminated site, PCE). The tensile strength of gasket materials, integrated with the deployed field capsules, is evaluated with time. In addition to testing under field conditions, tensile strength testing is also performed under controlled conditions in the laboratory to establish material degradation model. Computational modeling is used to simulate the site conditions of the installed capsules considering test sites’ hydraulic gradient, soil properties and plume concentration and the influence of such parameters on the rate of breakthrough within the installed capsules. The hydraulic parameters of gaskets were calibrated using field measurements and data from a series of experimental studies under controlled condition. Results indicated nonlinear power relationship for the mass breakthrough of benzene and PCE with time. Compared to chlorinated solvent, benzene has higher diffusivity among gasket materials (Neoprene, Buna-N, Viton). Viton showed the highest resistance to the diffusion of benzene and PCE. Viton and Neoprene showed the lowest and highest tensile strength degradation, respectively, once exposed to gasoline or chlorinated solvent contamination. Based on modeling results, benzene concentration breaking through the Neoprene and Buna-N will reach more than 70% and 60% of the monitoring well concentration, respectively, after 4 months. Benzene breakthrough reaches 85% to 9

Two swales (Mango Creek and I-40) treating highway runoff were retrofitted with simple check dams typically used for construction site sediment and erosion control to determine if these devices might improve post-construction stormwater management. The Mange Creek swale was retrofitted with a pair of standard rock check dams. The I-40 swale was retrofitted with a system of excelsior fiber wattle check dams and bags with proprietary phosphorus-adsorptive media (ViroPhosTM) to investigate if additional treatment for dissolved phosphorus was provided. Each swale was instrumented for approximately six months to collect data prior to the installation of check dams (pre-retrofit period) in March and April of 2014. Monitoring continued for an additional twelve months post-retrofit. Hydrologic data were collected at Mango Creek to examine peak flow mitigation and volume reduction imparted by the check dams due to additional storage and infiltration. Flow-proportional water quality samples were obtained to investigate removal of nitrogen and phosphorus species and total suspended solids (TSS) during the pre- and post-retrofit phases of the research. The inclusion of rock check dams in the Mango Creek swale did not significantly improve the volume reduction or peak flow mitigation of the SCM; however, these statistics were impacted substantially by the small pre-retrofit data set. Improvements were observed for volume reduction, peak flow mitigation, and hydraulic retention time, especially for small (<0.75 inch) and moderate (0.75-1.5 inch) rainfall events. Rock check dams did not significantly improve the removal rates of nutrients or TSS. However, these statistics were again impacted by the small pre-retrofit data set. Total nitrogen (TN) and total phosphorus (TP) concentrations from the highway were low compared to the literature, limiting the potential for significant reduction. Even so, TN and TP concentrations exiting the swale (0.81 mg/L and 0.13 mg/L, respectively) r

This report constitutes the second phase to document the water quality benefits of a stream restoration in the coastal plain of North Carolina. This phase compares the pre-restoration and post-restoration states of the water quality and hydrochemical signature of ‘the canal’ at the Claridge nursery in Goldsboro, NC. We made the hypothesis that a robust way to quantify the water quality benefits of this stream restoration was the use of cumulative nutrient load indicators. However, these indicators required the use of state-of-the-art instruments capable of capturing flow and water quality on a near continuous basis over the long term. After meticulous correction and all the necessary verifications, we were able to show that the restoration of the Claridge nursery canal, effectively creating a flowing wetland, was able to lower the nitrate loads by about 30% over three post-restoration consecutive years. This was accompanied by an overall carbon sequestration. The seasonality of the nitrate retention suggests that much of the nitrate unaccounted for was associated with the growth of vegetation, either through plant uptake and/or through denitrification associated with the release of organic matter from dead vegetation and the exchange conditions that they provided in the channel and with the floodplain. Increased residence time associated with the aquatic vegetation working as a filter time likely increased the capacity of the stream to retain nitrate. The seasonality of the nitrate retention may suggest that shorter monitoring periods could be chosen to represent a ‘summer’ vs. a ‘winter’ effect. However, averaging these effects would not necessarily represent the effective benefits over the long term. Instead, we suggest that monitoring should focus on cumulative indicators used over the long term for projects for which there is a high potential for nutrient retention. Fewer projects may have to be monitored, but using the necessary investment.

This report is an extension to the final report for NCDOT project 2004-15 “Value Engineering and Cost-Effectiveness of, Various Fiber Reinforced Polymers (FRP) Repair Systems”, submitted in June 2005. In that report, seventeen 30-ft long, prestressed concrete c-channels were tested under static and fatigue loading conditions using various carbon fiber reinforced, polymer (CFRP) strengthening systems to determine their structural behavior, cost effectiveness and constructability. The 2004, 15 final report also included the behavior of impact damaged AASHTO girders repaired by CFRP systems and tested under, fatigue loading conditions., This final report for NCDOT project 2006-10, summarizing the results of Phase II of the NCDOT project 2004-15, includes, the behavior of four additional c-channel prestressed concrete girders strengthened with externally bonded high modulus CFRP, sheets and high strength steel reinforced polymer (SRP) wire mesh. The report includes also the behavior of four additional, AASHTO type II girders. Two long-span AASHTO girders were tested static loading conditions to assess the performances of, FRP systems designed to repair impact damage. Two AASHTO girders were tested using short spans to determine the, effectiveness of using FRP to restore the shear capacity of impact damaged girders with one girder tested as control specimen and, one damaged then repaired with FRP. The repaired girder was stronger than the damaged girder, indicating that the FRP repair is, effective in restoring the girder shear capacity., Based on the above, the entire experimental program consisted of twenty-one girders strengthened with various FRP and, SRP materials and five AASHTO girders repaired with FRP to restore their flexural and shear capacities. The research indicates, that FRP systems are effective for the strengthening/repair of concrete highway bridges. The report provides detailed procedures, for installation as well as efficient inspection procedures to ensure effectiveness of the strengthening/repair systems.

Measured drawings., Main Street, HABS NC-199., This archival material has been provided for educational purposes. Ball State University Libraries recognizes that some historic items may include offensive content. Our statement regarding objectionable content is available at: https://dmr.bsu.edu/digital/about

El Álbum de la Mujer (1883-1890), una de las revistas literarias destinadas al público-lector femenino en México durante el siglo XIX tardío, ofrece una visión particular en cuanto al rol de la mujer de clase media en la sociedad. Entre las varias características que distinguen esta publicación de otras de la época –la dueña y directora extranjera, la inclusión de las perspectivas hispana e hispanoamericana y de grandes obras y autores literarios– la que sirve como enfoque de la presente investigación es el mercadeo del discurso científico a las mujeres decimonónicas. Una investigación detenida de la revista revela que la ciencia, lejos de sostener una única visión coherente en cuanto al lugar de la mujer en la sociedad, funcionaba como un espacio de negociación en el que coincidieron varias perspectivas inesperadas, tanto tradicionales como más resistentes y nuevas.

In response to growing traffic congestion, the North Carolina Department of Transportation will install North Carolina’s first ramp meters at four locations in the westbound direction of I-540 in Raleigh. The study outlined in this report addressed this need by developing a state-specific method that can be incorporated into NCDOT planning processes to evaluate any potential ramp metering projects in the future. The related frameworks of analysis were applied to the four westbound I-540 ramp meters to estimate the expected outcomes of the project. The I-540 analysis and frameworks resulting from this study focus on four major steps in the ramp metering process: 1) planning-level data collection, 2) planning-level analysis, 3) life cycle cost analysis, and 4) before-and-after installation evaluation. Ultimately, the research team found that westbound I-540 ramp meters will provide estimated benefits of between $28,234,500 and $73,410,500 over the next ten years. Although such future research is suggested, this study produces a sound foundation for evaluating ramp metering outcomes on which the state can build a ramp metering program that is both sustainable and efficient.

This is a data management plan for the Southeastern Transportation Research, Innovation, Development & Education Center (STRIDE) University Transportation Center (UTC). This data management plan was created in compliance with the US Department of Transportation’s “Plan to Increase Public Access to the Results of Federally-Funded Scientific Research” Version 1.1.

Work performed in this research project was in support of the effort by the North Carolina Department of Transportation to develop criteria to discern the need for undercutting soft soils and the adequacy of the subgrade after stabilization measures are implemented. The work was specifically focused on performing field testing and collecting data at a site located in the North Carolina Piedmont geologic area. Three test pads were constructed on comparable subgrade conditions with subgrade stabilization measures that included the use of select fill material and geosynthetic reinforcement coupled with a relatively thin layer of Aggregate Base Coarse (ABC). Field loading was applied using 1000 passes of a loaded construction truck. Several parameters were monitored during loading including stresses, deformation, and moisture and suction levels. A fourth pad was also constructed to test lime stabilization; however loading of this pad was not performed since the lime used for stabilization did not meet NCDOT’s specifications. A surface profiler (Lidar-based surveying) was used at periodic intervals to monitor plastic deformation and wheel path rutting with loading cycles. The field testing also included collection of data from Light Weight Deflectometer (LWD) and Dynamic Cone Penetrometer (DCP) to assess subgrade properties. Results indicated that the measured vertical stress near the interface of the subgrade for the geosynthetics-reinforced sections initially increased, but then decreased with increasing number of truck passes This decrease was attributed to progressive densification of the aggregate base course and the mobilization of the reinforced layer tensile strength. The reinforced sections experienced surface deformation on the order of 0.5-0.7 inches and the select fill-stabilized section showed a 1.2 inches of deformation after 1000 truck passes. In addition to the field data, two models were developed for the estimation of the resilient modulus (Mr) on the b

2014-32, The Institute for Transportation Research and Education at North Carolina State University conducted a follow-up study to, a previous North Carolina Department of Transportation (NCDOT) project, comparing mobile inventory data collection, vehicles to manually-collected data techniques. In the previous studies, sign retroreflectivity readings were either, captured with low degrees of accuracy or not captured at all. The follow-up study focused mainly on automated sign, retroreflectivity capture, but also looked at vendor capabilities regarding other sign features. The results show that, vendors can accurately locate the majority of signs. However, while vendors were unable to consistently capture sign, retroreflectivity readings within 10% accuracy, a comparison of MUTCD pass/fail ratings for signs for these vendors, showed that they captured ground-mounted signs with 88% and 97% accuracy, and overhead signs with 100% accuracy., Combining the sign location rates and the accuracy of the pass/fail comparison results in an overall accuracy ranging from, 63% to 70% which is comparable to the accuracy achieved by other sign management methods. Vendors also showed, some consistency in capturing the lower retroreflectivity readings, which should be more important to the NCDOT, as, MUTCD thresholds for failing signs are set at the lower level readings. Following location of the sign, vendors showed, promise collecting many of the other sign features, such as MUTCD code and roadside orientation, which showed, significant improvement from the previous study. This study shows that there is still room for improvement, but also, exhibits the improvements that vendors have already made in capturing all sign features.

98-1783, The effectiveness of sediment control devices was studied on a large NC DOT project to determine the, effects of different designs and conditions. Flow and sediment content of water exiting six different traps, and basins were measured and the amount of sediment trapped estimated from periodic surveys. Sediment, trapping and discharges strongly suggested that commonly used designs are relatively ineffective. The three, devices with rock dam outlets had sediment retention of <57% of sediment entering the traps and discharged, up to 20 t ac-1 during up to 12 months of monitoring. In contrast, the skimmer basins with surface outlets, stable sides and inlets, and porous baffles, retained more that 90% of sediment entering them, as long as they, were properly maintained. While the skimmer basins retained most of the sediment entering it, the, discharges were still relatively turbid and contained considerable suspended solids. The skimmer basin, which was monitored longest (one year) had average turbidity of 891 nephelpmetric turbidity units (NTU), and total suspended solids (TSS) of 537 mg L-1. It is likely that the remaining suspended materials are very, fine and will not settle by gravity alone under typical retention times. The more efficient designs tended to, retain more of the coarse fraction entering the basins than the less efficient designs. The improvement in, sediment retention with the design improvements will significantly reduce the impacts of land disturbances, from construction activity on water quality in nearby streams.

This project developed an analysis methodology and associated software implementation for the evaluation of, significant work zone impacts on freeways in North Carolina. The FREEVAL-WZ software tool allows the analyst, to predict the operational impacts of work zones, including impacts from capacity reductions, lane closures, reduced, speed limits and traffic diversions. The research is based on the 2010 Highway Capacity Manual Freeway Facilities, methodology and its companion FREEVAL-2010 computational engine. Through this project, the tool was, enhanced to allow for work-zone specific impact assessment, customized to the needs of the NCDOT Traffic, Management Unit. The tool includes a new planning-level feature that enables a quick assessment of work zone, impacts, while still allowing for a more detailed operational analysis. The tool uses default values for work zone, inputs specific for North Carolina conditions. However, all inputs can be adjusted by the user. Further, the, methodology allows the analyst to calculate user cost impacts of the work zone. All calculations and algorithms in, FREEVAL-WZ are consistent with the methodologies in the 2010 Highway Capacity Manual. The project included, a significant field validation and model calibration efforts with operational data collected directly by NCDOT using, field sensors. The data was used to compare predicted model performance to field operations and to develop default, parameters for typical North Carolina work zone configurations. Project deliverables include a final report, the, actual FREEVAL-WZ tool, and a software user manual.

Research experiments were designed and initiated to determine if application placement technologies offer, a viable solution for vegetation management along North Carolina Roadsides. Select equipment was evaluated for, broomsedge (Andropogon virginicus) control in centipedegrass rights of way as well as for plant growth regulator, applications along tall fescue (Festuca arundinacea) or bahiagrass (Paspalum notatum) roadsides in North Carolina., Research experiments were repeated in time. Evaluated application placement technologies included equipment, which incorporated mowing into the pesticide or plant growth regulator application as well as equipment that only, wiped the foliage., Much important data were collected and will aid in devising a more complete vegetation management, program for North Carolina Roadsides. Additionally, through this research, control options which incorporate, application placement technologies were identified for broomsedge control along North Carolina roadsides. This is, extremely important for NC DOT as control options had not been identified prior to completing this research., It appears Burch Wet Blade (also known as Diamond Wet Blade) would be the best fit for broomsedge control along, centipedegrass roadsides in North Carolina. With glyphosate (2 qt/a) applied through Burch Wet Blade at one, gallon per acre mown at four inches, we were able to obtain 90% broomsedge control through one year after, treatment. As for plant growth regulator applications along tall fescue or bahiagrass roadsides with application, placement technologies, in no instance were application placement technologies advantageous to a conventional, broadcast spray application. These data indicate application placement equipment would be beneficial to certain, aspects of vegetation management along North Carolina roadsides.

Accurate predictions of camber and prestress losses for prestressed concrete bridge girders are essential to minimizing the frequency and cost of construction problems. The time-dependent nature of prestress losses, variable concrete properties, and problems related to production variables make it difficult to predict camber accurately. The recent problems experienced by NCDOT during construction are mainly related to inaccurate prediction of camber. In this report, several factors related to girder production are shown to have a significant impact on the prediction of camber. A detailed method and an approximate method for predicting camber that both utilize adjustments to account for the production factors are proposed. The detailed method uses time-dependent losses calculations and creep factors to predict camber, while the approximate method uses multipliers. The current NCDOT method and the proposed methods are analyzed and compared using an extensive database of field measurements. The proposed methods are shown to provide significant improvements to the camber predictions in comparison to the current NCDOT method. Recommendations for design and production practices are provided.

The North Carolina Department of Transportation (NCDOT) operates several traffic management centers across the state, along with accompanying field devices such as traffic condition data stations, traffic surveillance cameras, and variable, message signs in addition to several regional incident management assistance patrols (IMAP). These centers currently operate, independently in an environment without dedicated center-to-center communication or seamless interaction. Efficient system, operation and management at the corridor and regional levels are severely hindered by this lack of integration. In order to, remedy this unacceptable situation thereby unleashing the potential for significantly reducing delay and increasing system, efficiency and reliability, NCDOT plans to procure a statewide ATMS systems., This ATMS procurement was planned to occur during the performance of this research project. However, the procurement, was delayed. Nonetheless the project achieved many of the original project goals. Although the baseline period did not come, to an end during the project, the research established the framework for data assembly and baseline performance assessment., The project included a comprehensive review to the state of the practice and research in ATMS performance measurement, and provided justification, data needs, and calculation methods for eighteen recommended performance measurements. The, project also developed and tested a method for categorizing route performance based on analysis of full travel time, distributions and developed and prototyped a multi-level reporting system for ongoing monitoring and assessment of ATMS, performance.

Chip seals provide a durable and functional pavement surface and serve as a highly economical highway, maintenance option when constructed properly. Data and literature suggest that chip seal sections constructed with, polymer-modified emulsions (PMEs) provide better initial and long-term performance and also extend the overall, service life of pavements. This project compares the performance of chip seals constructed with PME versus those, constructed with unmodified emulsion.

Horizontal curves are relatively dangerous features, with collision rates at least 1.5 times that of comparable tangent, sections on average. To help make these segments safer, this research developed consistent study methods with, which field personnel could examine curves. This research included an examination of curve crash characteristics, the development of a manual field investigation procedure, the development of calibration factors for the relevant, collision prediction equations in Highway Safety Manual, and GIS methods for finding key curve parameters., Based on this work, the research team recommends a systematic approach for identifying, investigating, analyzing, and evaluating horizontal curves. This systematic approach can lead to the selection and evaluation of promising, curves, assessment of funding sources, and a recommendation of appropriate countermeasures. The approach, should sometimes include a statistical analysis of horizontal curve collisions taking into account various road, crash, weather, and temporal attributes to help identify any unique circumstances that create an overrepresentation of, certain types or characteristics of collisions. The research team found a calibration factor of 1.33 for the collision, prediction equation for two-lane roads in the Highway Safety Manual. The research team also recommends several, methodologies to identify and measure the key characteristics of horizontal curves using data already stored in GIS, files.

Deicing salts and salt-water spray can cause serious corrosion problems for reinforced concrete bridge structures., These problems can lead to costly and labor-intensive repair and even replacement of the structure. Surface applied, corrosion inhibitors are potentially a useful and cost effective way to prolong the life of existing structures. The, purpose of this research project was to evaluate the effectiveness of commercially available corrosion inhibitors for, surface treatments of existing reinforced concrete bridges., Reinforced concrete specimens were cast with different levels of initial chloride contents, coated with one of six, products tested, and placed in accelerated corrosion environments. Each manufacturer donated their corresponding, products for use in the experiment. The manufacturers were also given the test matrix and parameters in advance of, the product application and invited to participate in the application process. Environmental conditions, voltmeter, and half cell potential readings were taken on a weekly basis in accordance with ASTM standards. Intermittently, some of these specimens were removed from their environments and evaluated on a visual, mass loss, strength loss, and chloride content basis. This data was then compiled and compared to each other and to control specimens, located in a non-corrosive environment., It was found that surface applied corrosion inhibitors delay the onset of corrosion and the speed of the corrosion, process. It was also found that a maximum chloride content of 0.5% by cement weight exists beyond which none of, the inhibitor products were useful. Suggestions for further research in this area of study are also included.

The North Carolina Department of Transportation (NCDOT) sponsored research aimed at enhancing the department’s, ability to assess the effectiveness of traveler information tools. The NCDOT has and will continue to make investments in, Intelligent Transportation Systems (ITS) that fall under the heading of Advanced Traveler Information Systems (ATIS). It, is critically important for the NCDOT to be able to assess the impacts, especially the network performance benefits, of, candidate ATIS investments in order to make well-informed project decisions and set funding priorities. This final report, documents the project’s findings, conclusions, and recommendations. The recommendations include the implementation of, an ATIS evaluation framework with DYNASMART-P as the primary integration tool and the development of a robust, ongoing data collection program to support ATIS research and evaluation.

Stormwater runoff from roadways is a source of surface water pollution in North Carolina. The North Carolina Department of Transportation (NCDOT) is required to implement stormwater control measures (SCMs) in the linear environment. NCDOT has specific interest in runoff from bridge decks, which is often discharged directly to a stream below. The research presented herein focuses on retrofit stormwater SCMs for bridge deck runoff management. Two bioretention basins and a swale were constructed in the easement of a bridge deck on I-540 at Mango Creek in Knightdale, North Carolina. One bioretention basin was sized to capture (without overtopping) runoff from the 0.7 inch event. The second basin was undersized by one-half (as compared to the large cell) and captured runoff from the 0.4 inch event. Undersized bioretention basins might often be used in retrofit situations when space is limited; therefore, it is important to understand how an undersized bioretention basin performs with respect to hydrology and water quality. Both bioretention basins employed 20 in (51 cm) of fill media, and had an internal water storage layer (IWS) of 2 ft (0.6 m) including the gravel drainage layer. The swale was designed to convey the ten-year storm event without overtopping. Runoff was piped from the northbound and southbound lanes to the bioretention basins and swale, respectively., Data collection began in October 2009 and continued through April 2010. Weirs and stage recorders were used to monitor inflow to and outflow from each SCM. Flow-proportional, composite water quality samples were obtained at the inlet and outlet of each SCM. Monitored water quality parameters included TKN, NO2,3-N, NH4-N, TN, TP, TSS, Cu, Zn, and Pb. TN was calculated by summing TKN and NO2,3-N. For small storms [those with less than 1 in (25 mm) rainfall depth], flow volume reductions for the large and small bioretention basins were 69% and 47%, respectively. This shows the hydrologic importance of properly sizing bioretention basins when space is available. However, some benefit is also associated with undersized systems, if space is too limited to allow for “full sizing.” There was a 23% volume reduction benefit associated with the swale., Average concentrations of TN (0.74 mg/L), TP (0.12 mg/L), and TSS (32 mg/L) from the bridge decks were relatively low when compared to other highways and paved surfaces previously monitored in North Carolina. Median effluent concentrations for the large bioretention basin were lower than those for the small bioretention basin for all nutrient forms and sediment.

This study investigated the effect of moisture and amount of baghouse fines on AC mixes. Two, types of baghouse fines, each with a different gradation, were used in varying concentrations to prepare, laboratory samples. The binder used was PG64-22 and the anti-strip additive used was LOF 6500., TSR (AASHTO T283) test results showed a reduction in retained strength for specimens without, additive as compared to the specimens containing additive showing the effectiveness of the additive in, preventing the moisture damage. Mixes with highest amount of baghouse fines showed resistance to, moisture damage in presence of the anti-strip additive. However, absence of additive reduced the strength, ratio considerably to the point that these mixes would be unacceptable under current NCDOT criterion., The mix performance was evaluated using the SST machine to determine the rutting and fatigue, characteristics of the mixes. In general, it was observed that moisture conditioning reduced rutting and, fatigue resistance of the mixes considerably, although, the TSR test result showed that an LOF-6500 antistrip, dosage of 0.5% was sufficient to reduce moisture damage to the point that the mixes would be, acceptable under the current NCDOT criterion of 85% retained strength.

In the U.S., there were more than 5,000 commuter rail diesel locomotives in use in 2011. Many of these have head end, power (HEP) engines that provide power for hotel services in the passenger cars. The North Carolina Department of, Transportation owns six diesel passenger locomotives that have recently replaced HEP engines. The general goal of this work, is to quantify the in-use emission rates of these engines on ultra low sulfur diesel (ULSD) fuel and evaluate the effect of soybased, B20 biodisel fuel on each engine. The specific research objectives are to: (1) evaluate the effect of engine load on, emission rates of CO, HC, NOx, and PM; (2) compare B20 versus ULSD with respect to emission rates of CO, HC, NOx, and PM, (3) compare to emission standards taking into account differences in measurement methods; (4) evaluate the inter-engine, variability in emission rates; and (5) estimate an emission inventory of CO, HC, NOx, and PM for the HEP engines. As, expected, fuel use and emission rates are sensitive to engine load. Cycle average PM emission rates were 20% lower for B20, than for ULSD, with no significant measured change in emission rates of other pollutants.

The intent of this study was to provide information necessary to characterize the present concentrations of an emerging transportation related contaminant, the platinum group metals (PGM), and to provide background information necessary to explore the potential uses of these metals as a specific marker of transportation related contamination that results from the discharge of road runoff into streams. Thirty-seven road crossings were evaluated in the Atlantic Slope of central North Carolina. Mussel tissue and sediment samples were collected from upstream and downstream of each road crossing. Samples were analyzed for the platinum group metal platinum (Pt), as well two other common transportation pollutants, lead and cadmium, and a common atmospheric pollutant, mercury. The enrichment of pollutants (downstream concentration -- upstream concentration) was compared to the number of vehicles crossing the stream. Local stream environmental variables and landscape scale variables were used to model the concentration of Pt in mussel tissue. Two 28-day laboratory toxicity tests, one with Pt and one with Pb, were conducted to assess the potential threat that current concentrations of these metals pose to native mussel fauna. The correlation of enrichment of the metals at bridge sites was weak for all metals studied. We hypothesize that complex hydrologic alteration caused by highway crossing structures was responsible for increased variation in downstream samples. Multiple samples taken from a single stream over an 8 km stream reach indicated that Pt concentrations in mussel tissue and sediment was enriched downstream of a road crossing, but the enrichment was not uniform and enrichment does not peak for several km downstream from the source. Results from the 28-day tests indicated that PGM may not pose an immediate threat to adult mussels and that mussels are a good sentinel species for studying PGM.

2014-13, This research effort examined the corridor impacts of various signal timing and geometric strategies to improve the, operational challenges observed at DDIs. A microsimulation analysis was conducted using a calibrated and validated DDI, modeled after the National Avenue and US-60 interchange in Springfield, Missouri. Four heavy volume scenarios were, tested in combination with seven categories of strategies. These strategies were selected from a larger pool of strategies, under the guidance of the NCDOT research panel and national expert recommendations. In addition to the microsimulation, effort, a cost analysis was conducted for the same strategies. Considerations were made for implementation cost, disruption, to user during implementation, and crash modification impacts. Finally, three sites in North Carolina were selected for field, study. In the microsimulation analysis, those strategies which reduced the number of phases at the downstream adjacent, intersection had the greatest benefit on the corridor routes for all four heavy volume scenarios. The reduction in phases, reduced loss time and increased capacity for the intersection. Unfortunately, these strategies were also the most expensive, alternatives studied, were likely to be the most disruptive to users during implementation.

2006-15, The research work presented in the report addresses the potential areas of conservatism in the current practice related to bridge, bents supported by drilled shafts and piles. The research encompasses modeling efforts and an experimental program. Modeling, includes analysis of existing bridge case studies with drilled shaft foundations to characterize the impact of the current, assumptions on sizing the various components of a bridge bent. An experimental program is performed to evaluate the, connection stiffness, and to determine if a given connection has sufficient capacity to develop such stiffness and transfer moment, The experimental program includes testing bearing pads in compression and shear to define their index properties. The bearing, pads are then tested in a prototype bridge set up to measure their performance under simulated loading., An improved set of design guidelines and recommendations regarding the superstructure-substructure connection’s rotational, stiffness, shaft/pile top boundary conditions, and resistance factors are proposed along with characterizing the impact of the, current practice and various design assumptions on sizing components of bridge bents. Resistance factors are developed for, drilled shafts, based on load test data from the state’s geologic regions, for compatibility with LRFD implementation. Work in, the report serves to provide a better understanding of the performance of bents supported by drilled shafts under AASHTO, loading conditions. Such understanding serves as a tool that provides NCDOT engineers with the flexibility of specifying the, level of conservatism to be built into a specific bridge bent design.

NCDOT Project 2014-11, The methodology provided in this report provides guidance for NCDOT conversions of two‐way, stop controlled intersections to other intersection types to enhance the effective allocation of, public funds. The findings of this project have been incorporated into the study’s primary, deliverable, the spreadsheet‐based NCDOT Intersection Life Cycle Cost Comparison Tool, which, combines enhanced HCM 2010 methodologies and standard cost benefit analysis methodologies, to calculate the long‐term net benefits of converting a two‐way stop controlled intersections to, three different intersection options: 1) all‐ way stop controlled, 2) signalized, and 3) roundabout, types. This deliverable is designed for use during the planning phase of potential intersection, conversion projects to help stakeholders identify the most cost‐effective conversion, configuration option. This report summarizes the findings of all project tasks.

NCDOT Project 2013¿09, This is the final project report of NCDOT research project 2013‐09: Delay and User Cost Estimation for Work Zones, on Urban Arterials. The project seeked to develop a methodology for quantifying delay and user cost impacts of, arterial work zones in North Carolina in an analytical framework, supported by NC‐specific empirical performance, data of arterial work zones. NCDOT recently acquired a similar methodology for the evaluation of significant work, zones on freeways, and this research aims to build on that prior effort to develop a companion tool for arterial, streets. Just as with the prior effort (NCDOT Research Project 2010‐08), the methodology developed in this project, would be implemented in a software tool, ARTVAL‐WZ, which can be used directly for in‐house analyses of these, types of work zones to assure seamless technology transfer of these research products. This report summarizes the, findings of all project tasks.

NCDOT Project 2000-05, This project assesses the feasibility implementing TRANSIMS to accomplish regional transportation modeling in North Carolina. The report summarizes TRANSIMS technology, its data and resource requirements, and typical output results. To gauge TRANSIMS resource requirements for a case study application, NCSU researchers examine the City of Fayetteville and its neighbor the US Army Fort Bragg military installation. In order to demonstrate and compare TRANSIMS to traditional techniques the NCSU research team develops interesting analogs with CORSIM and Tranplan for corridor and area traffic analysis. An Internet-based assessment tool generalizes the benefits and resource requirements of TRANSIMS for the Fayetteville - Fort Bragg case study, and the Internet site http://www4.ncsu.edu/~dsengup/indextransims.html summarizes the project findings. The research finds that Fayetteville and Fort Bragg offer an excellent technical opportunity to test prototype TRANSIMS methodology. However, personnel availability and other resource obligations at NCDOT necessitate deferring implementation of TRANSIMS to a future time.

The North Carolina Department of Transportation (NCDOT) is progressing toward developing quantitative and systematic, criteria that address the implementation of undercutting as a subgrade stabilization measure. As part of this effort, a, laboratory study and numerical analysis were performed from 2008 to 2010 with the results providing proposed criteria for, undercutting under various roadway site conditions and the adequacy of stabilization measures typically employed if, undercut was deemed necessary. These criteria provide provisions for discerning possible rutting and pumping of the, subgrade under construction loading, and provide response and subgrade stiffness under repeated loading of 10,000 cycles., The work in this report is focused on performing full-scale testing in the field on instrumented unpaved roadway sections to, collect data for the validation of guidelines developed from the laboratory and modeling study. Four 16 feet wide by 50 feet, long stabilized test sections were built on poor subgrade soils encountered in the Coastal Plain region of North Carolina., One test section encompassed undercutting and replacement with select material (Class II), the second and third test sections, included reinforcement using a geogrid and geotextile, respectively, in conjunction with undercutting and replacement with, ABC (Class IV), and a fourth test section included cement treatment of the soft subgrade soil. Full-scale testing was, conducted on the test pad by applying 1000 consecutive truck passes using a fully loaded tandem-axle dump truck over a, period of four days. During this time visual observations were noted and measurements were collected regarding rut depth, vertical stress increase at the base/subgrade interface, and subgrade moisture content with truck passes. Once trafficking, was completed, the test pad was re-graded and proof roll testing was performed to look for signs of pumping and rutting., Based on the field results, the proposed undercut criteria are evaluated in regards to the ability to discern the need for, undercutting as well as predict the performance of the stabilized test sections. Finally, a performance cost analysis is, conducted to illustrate the relative cost of each stabilization measure in relation to the measured performance (rutting) such, that an informed decision on cost-effective subgrade stabilization can be made.

North Carolina has experienced significant increases in truck traffic on many of its highways. Yet, current NCDOT, project-level highway traffic forecasts do not appropriately capture anticipated truck traffic growth. NCDOT, methods forecast total traffic AADT based on historical trends and assume base year and future year truck, percentages are the same. Also, NCDOT determines the growth factor of historical AADT traffic data by looking, only at the first year and the last year ignoring intermediate year traffic data. This research recommends that traffic, for dual axle (Dual) trucks and tractor trailer (TTST) trucks be separately forecast using an average growth factor, (AGF) method that uses all available data and calculates growth factors year by year and averages them for the, historical trend. The results of this research propose statistical methods to separately estimate growth factors for, light vehicles (Cars), Duals and TTSTs. In this study Cars represent FHWA vehicle classes 1-3, Duals 4-7 and, TTSTs 8-13. The methods have modest data requirements based on NCDOT traffic counts and VTRIS on-line, traffic data. Statistical guidelines including mean AGFs and confidence intervals to help refine the estimates for, growth factors by vehicle class and highway type. Case study examples demonstrate the methods and guidelines for, Interstate, US, and NC highways. Other issues are explored including the effects of increased truck traffic on, highway level of service and pavement design.

This report presents an improvement in the rolling protocol for chip seals based on an evaluation of aggregate, retention performance and aggregate embedment depth. The flip-over test (FOT), Vialit test, modified sand circle, test, digital image processing technique, and the third-scale Model Mobile Loading Simulator (MMLS3) are, employed to evaluate the effects of the various rolling parameters and to measure chip seal performance. The, samples used to evaluate the chip seal rolling protocol were obtained directly from field construction. In order to, determine the optimal rolling protocol, the effects of roller type, number of coverages, coverage distribution on the, sublayers of a multiple chip seal (i.e., the split seal and triple seal), and rolling pattern are evaluated using the results, of aggregate retention performance tests, the modified sand circle method, and the digital image process. It is found, that two types of roller, the pneumatic tire roller and the combination roller, are recommended as the optimal rollers, for the chip seal. In addition, it is found that the optimal number of coverages for the chip seal is three coverages., Moreover, the performance of the triple seal without coverage at the bottom layer does not affect the aggregate, retention performance, although the split seal does require coverage at the bottom layer. Finally, it is found from the, MMLS3 results that the delayed rolling time between the spreading of the aggregate and the initial rolling, significantly affects the aggregate loss, and that the delayed rolling time is related to the aggregate moisture, condition and the ambient temperature. Effects of different rolling patterns are investigated based on the delayed, rolling time and roller speeds, and recommendations are developed for two- and three-roller scenarios.

Research experiments were designed and initiated to evaluate plant growth regulators and recently registered herbicides, for vegetation management along North Carolina roadsides, as well as warm-season turfgrass seed and sod practices to utilize, low-growing, mat-forming species that require reduced inputs. All experiments were repeated in location and/or time, and have, produced three peer-reviewed publications to date in Crop Science or Weed Technology journals. Results from this project, suggest plant growth regulators may be used to reduce annual mowing events, which can result in cost-savings as well as reduced, mowing operator requirements in areas that pose increased safety risks. Greenhouse research identified NC agronomic and, specialty crops that Esplanade (active ingredient: indaziflam), a relatively new PRE herbicide, may be safely applied near without, objectionable drift concerns, while field trials evaluated this herbicide and others for warm-season release programs., Additionally, greenhouse research confirmed Esplanade and Proclipse (active ingredient: prodiamine) applied PRE provide, excellent annual ryegrass (Lolium multiflorum L.) control. Field research identified herbicide application timings with respect to, season and mowing operations to improve current vaseygrass (Paspalum urvillei Steud.) control programs. Lastly, zoysiagrass, (Zoysia spp.) sodding field trials identified cultivars, planting preparation techniques, and planting timings that resulted in, successful establishment along guardrails, while warm-season turfgrass seeding resulted in unacceptable establishment. This, information may be utilized by the North Carolina Department of Transportation – Roadside Environmental Unit to help improve, comprehensive vegetation management practices that reduce long-term inputs while providing safe thoroughfares for motorists.

An efficient and accurate inventory of a state highway agency’s assets, along with the means to assess the condition, of those assets and model their performance, is critical to enabling an agency to make informed investment decisions, in a Transportation Asset Management (TAM) environment. Today, new technologies provide fast and improved, ways to gather, process, and analyze data. The key is to identify and gather the most useful, reliable, cost-effect, information and use it to make informed decisions for asset management., Four key infrastructure areas have been identified as primary asset components; pavements, bridges, geotechnical, features, and roadside appurtenances. Each area contains multiple categories and data elements important for sound, decision making. Although some similarities exist in these four primary categories, the nature of data collection may, differ, depending on the asset type. The, sheer number of data elements and the length of asset networks for, pavements and roadside appurtenances render the automated highway speed data collection method a necessity, rather than a luxury. However, the discrete nature of bridges and geotechnical features make the automated mobile, data collection method on a network level unfeasible with today’s technology., Important issues in the collection process include precision, subjectivity and variability of the process itself, as well, as speed, safety of the survey crew, proximity of the public, cost, etc. Although previous research has attempted to, address these issues and determine the most appropriate method(s), the question remains as to which roadway data, collection system is best for state highway agencies given real world constraints. This research set up a “sealed, envelope” experiment wherein the identification, location, description, and quality of the asset data elements are, known only to NCSU researchers. Vendors are informed of only the data necessary to perform their evaluation. To, support this effort at 95-mile test course near Raleigh, North Carolina was identified, which contained a sampling of, pavement, roadside, geotechnical and bridge elements. This document reports on the findings from the study.

Field data for in-use fuel consumption and emission rates were collected for 15 nonroad vehicles using a portable emission, measurement system (PEMS). Each vehicle, including 5 backhoes, 4 front end loaders, and 6 motor graders, were tested, once on petroleum diesel and once on B20 biodiesel. The vehicles included different model years and thus represent a, variety of engine certification tiers. A methodology was developed for study design, field data collection, data screening and, quality assurance, data analysis, and benchmarking of the data. The average rate of loss of data due to data quality issues was, 6.9%. On average, over 3 hours of valid data were collected in each test. Time-based emission factors were found to, increase monotonically with respect to engine manifold absolute pressure. Fuel-based emission factors were mainly sensitive, to differences between idle and non-idle engine operation. Typical duty cycles were quantified in terms of frequency, distributions of manifold absolute pressure (MAP) and used to estimate cycle average emission factors. On average, the use, of B20 instead of petroleum diesel lead to an insignificant 1.8% decrease in NO emission rate and significant decreases of 18, 26, and 25% for opacity, HC, and CO, respectively. Emission rates were also found to decrease significantly when, comparing newer, higher tier vehicles to lower ones. Fuel use rate, and NO, HC, and CO emission factors, were found to be, of similar magnitude as independent benchmark data. An emissions inventory was developed for these vehicles. The current, fuel mix of B20 and petroleum diesel is estimated to produce 0.4 to 6.4 percent lower emissions, depending on the pollutant, than usage of 100 percent petroleum diesel. If NCDOT were to use 100% B20 in the same vehicles, then additional, reductions in emissions of each pollutant would be approximately 2.0% to 36.9% lower than for the current fuel mix of B20, and petroleum diesel. Although higher tier engines have lower emissions factors for each pollutant than lower tier engines, their annual average emissions tend to be higher because of greater utilization. Specific recommendations are made for, future work, including expansion of the use of B20 to further reduce tailpipe emissions in the NCDOT inventory, replacement of older vehicles with newer ones, field data for larger sample sizes of vehicles for each Tier in order to improve, confidence in the emissions factors and inventories, assessment of Tier 4 vehicles as they become available using improved, instrumentation, evaluation of fuel formulations, evaluations of other vehicle types, and others.

The Mechanistic-Empirical Pavement Design Guide (MEPDG) 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. To support the MEPDG NCDOT needs site-specific truck classification counts, truck axle load spectra, regional average seasonal adjustment factors, and forecasting methods for truck class volumes. This research, proposal addresses these NCDOT traffic data and forecasting needs for implementing the MEPDG., The research produced the following results: (1) software to process and clean WIM data; (2) database of high, quality, clean NCDOT vehicle class counts and weight data; (3) simulation studies to guide the selection of, sensitive traffic data and traffic count locations; (4) techniques for traffic data clustering and seasonal analysis of, vehicle classification and truck axle loadings; (5) software to prepare datasets and sampling plans for Levels 1, 2, and 3 MEPDG requirements (Level 1 site specific, Level 2 seasonal groupings, and Level 3 statewide averages); (6), site specific, regional and statewide NC traffic data inputs for Levels 1, 2, and 3 in the MEPDG procedures for, vehicle class distributions and axle load spectra including seasonality; (7) vehicle class forecasting methods for, MEPDG procedures; (8) case study demonstrations and analyses; and (9) implementation and management plan for, MEPDG traffic data.

Many construction projects involve the need to pump turbid water from borrow pits or other excavations into stilling, basins or sediment bags prior to discharge. The design and operation of these basins needs to be optimized to, provide the best water treatment prior to discharge. This project was designed to provide an evaluation of stilling, basin designs and polyacrylamide (PAM) injection to minimize turbidity in discharged water. A Piedmont subsoil, was mixed with water in a large holding pond which served as a source of the turbid water which was pumped into, the stilling basin. Initial turbidities were in the range of 250-400 nephelometric turbidity units (NTU) in the source, basin. Physical changes to the open basin, both with porous baffles and distribution along the bottom, significantly, reduced turbidity or total suspended solids in the stilling basin, but the highest reduction was only 25%. Chemical, treatment with PAM reduced turbidity and TSS by up to 88% and 84%, respectively, with little effect from the, baffles or bottom spreader. Both types of PAM dosing systems worked well. There was some evidence that flocs, formed after PAM treatment were intercepted by the dam slope. The porous baffle with 10% open pore space was, significantly more effective than the baffle with 45% open pore space, but only when no PAM was added. The, PAM treatments were highly effective and should be relatively simple and economical to use to reduce turbidity in, pumped water.

This research report is geared at providing guidance to NCDOT for when to consider marking crosswalks at, uncontrolled approaches for pedestrians, installing pedestrian signal heads at existing signalized intersections, or, providing supplemental treatments at a crossing location., The primary deliverable of the project, the crosswalk assessment flowchart, is intended to be a self-contained, wall-mounted, poster that fully describes most aspects of the evaluation and decision-making process. This report is intended, to supplement that flowchart, providing background for the flowchart with references to research and underlying data, used to develop the guidance., The guidelines principally consist of four parts: Step 1) Document Existing Characteristics / Signalized Crossing, Assessment, Step 2) Unsignalized Crossing or Midblock Crossing Assessment, Step 3) Additional / Alternative, Treatments Assessment, and Step 4) Pedestrian Hybrid Beacon (PHB) Assessment.

NCDOT/NC/2012-0731, This study details the research team’s approach and findings for mapping transportation-disadvantaged, populations and holding interviews with local practitioners and vulnerable groups The study provides a, straightforward and practice-ready outreach process that can be used by transportation practitioners to, better address the needs of populations facing significant mobility challenges. Underserved groups in six, North Carolina counties (Beaufort, Chatham, Graham, Wake, Warren, Wilson) are identified and mapped, with GIS applications. Most often those protected under Title VI requirements – low-income and minority, populations – but also the elderly, disabled, children, and those with language barriers have mobility, needs that are often unmet., Interview findings demonstrated that policy provisions, such as restrictive eligibility requirements for, paratransit, prohibitive monetary and time costs, and insufficient public transportation offerings, among, other reasons, pointed to why certain groups suffer transportation disadvantage., This study also provides transportation practitioners with a step-by-step process to identify and map, transportation-disadvantage populations in a user-friendly Practitioner Guide. The guide serves as a, companion to the research and is included in the appendix of this report.