bluuebunny/crossref_metadata_2025 huggingface dataset:
Mechanistic–Empirical Study of Effects of Truck Tire Pressure on Pavement
Authors: Wang Feng , Machemehl Randy B.
Published: May 2018

Truck tire pressure plays an important role in the tire–pavement interaction process. As a traditional approximation method in many pavement studies, tire–pavement contact stress is frequently assumed to be uniformly distributed over a circular contact area and simply equal to the tire pressure. However, recent studies have demonstrated that the tire–pavement contact stress is far from uniformly distributed. In this study, measured tire–pavement contact stress data were input to a finite element program to compute pavement immediate responses for three tire configurations: single tires, dual tires, and dual-tire tandem axles. Computed critical pavement responses were input to pavement distress transfer functions to analyze further the effects of tire inflation pressure on pavement performance. Two asphalt concrete pavement structures–-a thick pavement and a thin pavement–-were investigated. Pavement responses at selected locations in the pavement structures were computed by the finite element program using the measured tire–pavement contact stress data and compared with the results predicted by a multilayer program using the traditional uniform contact stress method. The computation results showed that the multilayer program and the traditional tire model tend to overestimate the horizontal tensile strains at the bottom of the asphalt concrete and underestimate the vertical compressive strains at the top of the subgrade. Prediction of effects of tire pressure on pavement performance shows that increased tire pressure results in increased pavement distress due to both cracking and rutting and that tire inflation pressure is also related to the shape of pavement ruts.
Seasonal Time Series Models to Support Traffic Input Data for Mechanistic–Empirical Design Guide
Authors: Prozzi Jorge A. , Hong Feng
Published: May 2018

To predict the performance of pavements, traffic volume should be forecast for the design life. Two aspects associated with traffic volume forecasting are incorporated into the NCHRP Project 1–37A mechanistic–empirical (M-E) design guide: long-term annual growth and short-term seasonal variation. Annual traffic growth can be accounted for by either a linear or a compound trend model. Seasonal traffic variation is captured by monthly adjustment factors. Class-specific traffic forecasting improves design accuracy but implies increased efforts in traffic data input and computer running time. Long-term and short-term estimations are performed independently and separately. This study demonstrates that the characterization of traffic volume is better achieved by estimating growth trends and seasonality simultaneously. Because of the data-intensive nature of the M-E design guide, any efforts toward facilitating data processing and input should be pursued. In this paper, seasonal time series techniques are applied to integrate both the long- and short-term aspects into one model. The growth trend term in a time series model predicts traffic volume as a function of time in years, and trigonometric functions are used to capture seasonal variations. The results show that the seasonal time series technique is both effective and efficient. In addition, similarities and differences regarding traffic growth trends and seasonality among different vehicle classes are easily identified through the parameter estimates. Finally, the study statistically demonstrates that long-term information generating growth trends and short-term information generating seasonal variability can be combined to predict traffic for M-E design in a more efficient way.
Framework for Automatic Condition Assessment of Culverts
Authors: Meegoda Jay N. , Juliano Thomas M. , Banerjee Amit
Published: May 2018

A framework for real-time and automated monitoring of the condition of culverts based on identifying internal defects via video inspection is developed. Manual inspection using closed-circuit television has several drawbacks, such as inconsistency and subjectivity due to human evaluation. Analysis of digital video, consisting of thousands of megabytes even at lower resolutions, can be laborious and not suited for real-time implementation. An innovative approach is to extract image frames judiciously from the video and analyze frames to locate and categorize major defects. Rather than analyze all extracted frames, one can skip consecutive frames at a minimal loss of accuracy and bring considerable savings in memory and system requirements. Each frame is preprocessed to enhance contrast, through use of an adaptive scheme, and to reduce dimensionality in pixel-space by implemention of region-based processing. Preprocessing is followed by a two-step image segmentation process, which implements a background elimination procedure in the first step and shape detection in the second step. Fuzzy clustering is used as the underlying segmentation model. Defect shape and depth information after post-processing are used as input to an assessment methodology for automated condition state. A simple formulation based on both the damage area and depth is then used to assess the condition of culverts based on a four-point condition assessment scale. The proposed framework is demonstrated with a test example. Future research would entail consolidating the concept by extensive testing and integration for real-time application.
Integrated Approach to Pavement Marking Management
Authors: Hawkins Neal , Smadi Omar , Hans Zach , Maze Thomas H.
Published: May 2018

Providing good pavement marking performance is an essential component of the transportation system. According to Tom Welch, state safety engineer for the Iowa Department of Transportation (DOT), “Every older driver forum has included a consistent demand for brighter and more durable pavement markings.” This paper summarizes some management tools developed for Iowa DOT as part of a pavement marking management system (PMMS). A summary of how retroreflectivity data are used statewide in managing pavement marking performance is provided as well as a discussion of how the PMMS was integrated with other infrastructure management resources for Iowa DOT.
Snowstorm Event–Based Crash Analysis
Authors: Qin Xiao , Noyce David A. , Lee Chanyoung , Kinar John R.
Published: May 2018

This study investigated the impact of snowstorms on a roadway system and assessed winter maintenance efforts in improving highway safety from a macroscopic perspective. The Wisconsin State Trunk Highway System was used as the data source. An inverse relationship between deicing material consumption and crash counts during snowstorms is reflected in the analysis; it also implies multiple causes of snowstorm crashes. Primary factors considered in this research were the effects of various weather conditions and winter maintenance. Results showed a mixed influence of both the snowstorm severity and winter maintenance investment on road safety. That is, severity of the snowstorm in regard to duration, intensity, and wind speed increases traffic crashes and casualties with simultaneous consumption of more deicing materials and labors. The research also explicitly proves that a proactive winter maintenance effort significantly improves traffic safety. Temporal distribution of crash occurrence during a snowstorm shows that a large percentage of crashes occurred during initial stages of the snowstorms, probably because snow removal activities had not yet begun. The pattern is quite similar for state-maintained highways and local roads, except that in the second half of a snowstorm, a higher percentage of crashes occur on local roads than on state highways, possibly suggesting that the different level of maintenance and use of deicing materials may play an important role. Additional research is required to quantify the effects of deicing materials specifically, particularly in regard to application rate and frequency, on highway safety.
Fast-Track Construction for Concrete Pavement Rehabilitation
Authors: Lee Eul-Bum , Choi Kunhee
Published: May 2018

This case study presents an innovative fast-track reconstruction approach applied to a heavily trafficked Long-Life (30-plus years) Pavement Rehabilitation Strategies (LLPRS) project on I-15 in Devore in Southern California. A 4.5-km stretch of badly damaged concrete truck lanes was rebuilt over two 215-h (approximately 9-day) periods with one-roadbed full closures with counterflow traffic and around-the-clock (24 h per day/7 days per week) construction operations. The same project would have taken 10 months to complete with traditional nighttime closures. State-of-practice technologies were adopted on this Rapid Rehab project to accelerate construction, mitigate traffic disruptions, and propagate project information. From the initial planning and design stages, engineers used CA4PRS (Construction Analysis for Pavement Rehabilitation Strategies) software incorporated with traffic simulation models to develop an optimal and economical rehabilitation scenario. Postconstruction data validated the preconstruction analysis and simulation estimates of productivity and traffic delays. Because of the implementation of an Automated Work Zone Information System and proactive public outreach, a 20% reduction in traffic demand through the construction work zone was achieved and thereby reduced the maximum peak hour delay to a “tolerable” level. Surveys on the project website showed dramatic changes in public perception of the Rapid Rehab extended closures approach from initial reluctance and objection to positive support. Advantages of using this method of fast-track accelerated highway reconstruction included less traffic disruption for the traveling public, longer (more than 30 years) pavement life expectancy, improved safety for motorists and workers, and reduced agency cost compared with the traditional approach using repeated nighttime closures.
Calibration of NCHRP 1–37A Software for the Washington State Department of Transportation
Authors: Li Jianhua , Muench Stephen T. , Mahoney Joe P. , Sivaneswaran Nadarajah , Pierce Linda M.
Published: May 2018

A significant amount of Washington State Department of Transportation (WSDOT) portland cement concrete (PCC) pavement that was placed in the 1960s is nearing the end of its serviceable life and must soon be rehabilitated or replaced. Initial WSDOT estimates place the cost of the anticipated work at more than $600 million. A tool to predict PCC pavement deterioration and ultimate failure is needed to prioritize rehabilitation and reconstruction efforts best. The software associated with NCHRP Project 1–37A was chosen as a promising tool worthy of assessment for this application. The urgency of the situation necessitated its use, despite the lack of formal calibration guidance, some software bugs, and isolated model inconsistencies. A procedure was developed and used to calibrate the rigid pavement portion of the NCHRP 1–37A software to data obtained from the Washington State Pavement Management System (WSPMS). Significant findings resulted: ( a) the rigid pavement portion of the software was calibrated successfully; ( b) WSDOT pavements require calibration factors significantly different from default values; ( c) the software does not model longitudinal cracking, which is significant in WSDOT pavements; ( d) WSPMS does not separate longitudinal and transverse cracking, a lack that makes calibration of the software's transverse cracking model difficult; and ( e) the software does not model studded tire wear, which is significant in WSDOT pavements. Results indicate that the calibrated software can be used to predict future deterioration caused by faulting, but it cannot be used to predict cracking caused by the transverse or longitudinal crack issues.
Validation of Material-Level Performance Models
Authors: Lee S. Joon , Seo Youngguk , Kim Y. Richard
Published: May 2018

A mechanistic pavement analysis with laboratory fatigue cracking and rutting models was validated with the response and performance measured from asphalt pavements. Asphalt pavements with different air void contents were tested using the third-scale Model Mobile Loading Simulator (MMLS3). The fatigue life prediction algorithm adopts a cumulative damage analysis; the permanent deformation prediction algorithm uses a sublayering method. These algorithms, which are similar to the ones adopted in the NCHRP 1–37A Mechanistic–Empirical Pavement Design Guide (MEPDG), account for the loading rate and temperature variation along the depth of the pavements. The major difference between the algorithms used in this study and the ones in the MEPDG is that the difference in loading frequencies between the laboratory test method and the MMLS3 test was accounted for in this study using the time–temperature superposition principle with growing damage. The predictions of fatigue life and permanent deformation growth in the MMLS3 tests revealed that the proposed algorithms do a reasonable job in predicting these parameters, although improved predictions may be achieved by adopting more fundamental models. It is expected that the resulting alliance between the accelerated pavement test, laboratory material level test, and performance models can serve as a cornerstone for the successful estimation of the service life of in situ pavements.
Using Macrolevel Collision Prediction Models in Road Safety Planning Applications
Authors: Lovegrove Gordon R. , Sayed Tarek
Published: May 2018

This paper describes the use of several recently developed macrolevel collision prediction models (CPMs) in two road safety planning applications. Data from several urban neighborhoods in the Greater Vancouver Regional District (GVRD) in the province of British Columbia, Canada, were used to present and test model-use guidelines in two road safety planning applications. In the first case study, an areawide traffic calming collision modification factor was estimated for GVRD urban areas, for “total” and “severe” collisions, to be in the range of –0.40 and –0.39, respectively. In the second case study, four neighborhood network structures were evaluated, and two test networks that appeared safer than conventional grid and cul-de-sac neighborhood street patterns were revealed, mostly because of the increased use of three-way intersections. Moreover, cul-de-sac networks appeared to be much safer than grid networks, by nearly three to one. The results suggested that the models and model-use guidelines could complement and enhance traditional road safety improvement programs and could provide new and improved empirical tools for planners and engineers to do road safety planning. It is hoped that development of guidelines for macrolevel CPM use will facilitate improved decisions by community planners and engineers and, ultimately, neighborhood traffic safety for residents and other road users.
Influence of Seed Layer Moduli on Finite Element Method–Based Modulus Backcalculation Results
Authors: Matsui Kunihito , Hachiya Yoshitaka , Maina James W. , Kikuta Yukio , Nagae Tasuku
Published: May 2018

The determination of pavement layer moduli from falling weight deflectometer test data is known as backcalculation analysis. Generally, backcalculation analysis is unstable–-greatly influenced by several causes of error. They may be categorized as modeling error in the forward analysis, deflection measurement error, or numerical computation error due to instability in the backcalculation procedure, for example. Because of these problems, the seed values selected for layer moduli greatly influence backcalculation results. To reduce the effects of measurement error, truncated singular-value decomposition is used for regularization. Variable scaling, often used in optimization algorithms, is implemented to improve numerical accuracy. A Ritz vector reduction method is used to solve a large system of dynamic equations in dynamic backcalculation efficiently, and various other means are introduced to decrease computational time. Recent updates of Dynamic Back Analysis for Layer Moduli software, first developed in 1993 and whose solver is based on axi-symmetric finite element method, are presented, as are examples of airfield pavement applications. Results are compared with results from Back Analysis for Layer Moduli static backcalculation software, whose solver was developed using multilayered linear elastic theory. Experience indicates that a dynamic backcalculation is superior to static back-calculation. The results from the two methods are presented and compared.
Field Validation of Airport Pavement Granular Layer Rutting Predictions
Authors: Kim In Tai , Tutumluer Erol
Published: May 2018

This paper presents research findings on the prediction performances and field validations of the recently developed granular base–subbase layer permanent deformation models using the full-scale pavement test section data from the FAA's National Airport Pavement Test Facility (NAPTF). The FAA-designated P209/P154 aggregate materials were used in the construction and testing of the NAPTF flexible pavement test sections with variable-thickness base and subbase courses. To account for the rutting performances of these substantially thick granular layers, a comprehensive set of repeated load triaxial tests, considering both constant and variable confining pressure (CCP and VCP) conditions, were conducted on the P209 base and P154 subbase granular materials. On the basis of the laboratory test results, both CCP- and VCP-type permanent deformation models were developed to predict maximum ruts that occurred at the NAPTF under both six-wheel and four-wheel gear loadings applied following a wander pattern. The developed rutting models were first calibrated for the field conditions and then evaluated for predicting the field accumulation of permanent deformations by properly taking into account the NAPTF trafficking data, effects of stress rotation due to moving wheel loads, and loading stress history effects. A comparison of the measured and predicted permanent deformations indicated that a good match for the measured rut magnitudes and the accumulation rates could be achieved only when the magnitudes and variations of stress states in the granular layers, number of load applications, gear load wander patterns, previous loading stress history effects, trafficking speed or loading rate effects, and finally, principal stress rotation effects due to moving wheel loads were properly accounted for in the laboratory testing and permanent deformation model development.
Development of Cement-Treated Base Material for Reducing Shrinkage Cracks
Authors: Cho Yoon-Ho , Lee Kang-Won , Ryu Sung-Woo
Published: May 2018

This paper describes an approach to minimizing the amount of shrinkage cracking in a cement-treated base (CTB). CTB is a stiff base that features higher rutting resistance and reduced fatigue cracking because of its ability to distribute traffic loads. However, it has not been applied to asphalt pavement in South Korea because of the possibility of reflection cracks. The goal of this study was to develop a cement-treated base with a lower shrinkage and thereby prevent cracks. After factors contributing to dry shrinkage were identified and the composition and properties of each admixture were analyzed, laboratory and field tests were designed and performed. The preliminary test results suggested a mix design of 25% fly ash. The amount of cement was set at 7% for all mixes to satisfy the specification standard for allowed strength in South Korea. On the basis of the experiment results, and considering strength, shrinkage, and economic efficiency, two mix designs were selected: a mixture containing 25% fly ash and a mixture containing 25% fly ash with 10% expansive additive. The field tests focused on crack propagation suggested that the optimal mixing alternative of a cement-treated base was the mix design of 25% fly ash and 10% expansive additive.
Crash Estimation at Signalized Intersections
Authors: Wang Xuesong , Abdel-Aty Mohamed , Brady Patrick A.
Published: May 2018

Longitudinal intersection crash data are observations on a cross section of intersections that are observed over several time periods. Such cross-section and time series data structures have positive temporal correlation within each intersection. Using the basic negative binomial regression leads to invalid statistical inference due to incorrect test statistics and standard errors that are based on the misspecified variance. Generalized estimating equations (GEEs) provide an extension of generalized linear models to the analysis of longitudinal data, which account for the correlation in the repeated observations for a given intersection. In this study, the GEE procedure was used to model the temporal correlation for longitudinal intersection crash data. This analysis was based on 3-year data for 208 four-legged signalized intersections in central Florida. Intersection crash frequencies were fitted through use of GEEs with a negative binomial link function for four correlation structures. Both the functional form and the link function of GEE models were assessed with the cumulative residuals method. This method showed that the total average daily traffic per lane was the best representation of traffic volume, and the GEE model with autoregression structure had the best model performance. Variable relative effect analysis identified the relative effect for the variables in the models. Intersections with heavy traffic, a larger total number of lanes, a large number of phases per cycle, and high speed limits and those in high population areas were correlated with high crash frequencies. The intersections with more exclusive right-turn lanes and with a partial left-turn protection phase had lower crash risks.
Comprehensive Analysis of the Relationship between Real-Time Traffic Surveillance Data and Rear-End Crashes on Freeways
Authors: Pande Anurag , Abdel-Aty Mohamed
Published: May 2018

Rear-end collisions are the single most frequent type of crash on freeways. Their impact on freeway operation is also most noticeable because almost all of them occur during periods of medium to heavy demand. Preliminary explorations of average traffic speeds before a crash measured at loop detector stations surrounding the crash location showed that rear-end crashes can be placed into two mutually exclusive groups: first, those that occur under extended congestion and, second, those that occur with relatively free-flow conditions prevailing 5 to 10 min before the crash. With loop detector data preceding these two groups of rear-end crashes contrasted with randomly selected noncrash data, it was found that the first group can be attributed to parameters such as the coefficient of variation in speed and average occupancy measurable through loop detectors at stations in the close vicinity of the crash location. For the second group, traffic parameters such as average speed and occupancy at stations downstream of the crash location were significant as were off-line factors such as the time of day and presence of an on-ramp in the downstream direction. It was also observed that traffic conditions belonging to the first segment occurred rarely on the freeway but still made up about half the rear-end crashes. This observation, along with neural network–based classifiers, has been used to propose a strategy for real-time identification of conditions prone to the rear-end crashes. The strategy can potentially identify almost 75% of rear-end crashes, with reasonable false alarms.
Right Turn from Driveways Followed by U-Turn on Four-Lane Arterials
Authors: Pirinccioglu Fatih , Lu Jian John , Liu Pan , Sokolow Gary
Published: May 2018

This paper evaluated the safety effects of right turns followed by U-turns (RTUT) at signalized intersections and at unsignalized median openings as an alternative to direct left turns (DLT) from driveways or side streets on four-lane arterials. The safety of both alternatives was evaluated on the basis of traffic conflict analysis. Nine types of conflicts were used for this study. Five of the conflict types were related to RTUT movements, while the rest were related to DLT movements. More than 500 h of data were collected at 16 sites with the help of video recording equipment. Data collection sites were divided into two sets by geometric criteria. At the first set of sites, the drivers had to complete the U-turn movement of RTUT at a signalized intersection. In contrast, at the second set of sites, the U-turns were at unsignalized median openings. At signalized intersection sites, DLT movements generated two times as many conflicts per hour as RTUT movements. When the effects of traffic volumes were taken into consideration, RTUT movements had a 5% higher conflict rate than DLT movements. Severity comparison of DLT and RTUT movements indicated that RTUT-related conflicts were less severe than DLT-related conflicts. At unsignalized median opening sites, DLT movements generated 10% more conflicts per hour than RTUT movements. Furthermore, another conflict rate (conflicts per 1,000 vehicles involved), which takes the effect of traffic volumes into consideration, was 62% higher for DLT movements than for RTUT movements. Severity analysis results indicated that DLT movements had higher average severity scores than RTUT movements.
Safety Comparison of New Jersey Jug Handle Intersections and Conventional Intersections
Authors: Jagannathan Ramanujan (Ram) , Gimbel MaryAnn , Bared Joe G. , Hughes Warren E. , Persaud Bhagwant , Lyon Craig
Published: May 2018

New Jersey jug handle intersections (NJJI) have been around for the past few decades. The basic design philosophy behind implementing jug handle intersections at suitable locations is to improve traffic operations by the elimination of the left-turn phase on a major road and to improve traffic safety by a reduction of the total number of potential conflict points and specific conflicting maneuvers at the intersection. This study, based on statistical analyses of intersection crash data, investigates the differences between and similarities in safety performance of NJJIs and conventional intersections for a limited sample set of 44 NJJIs and 50 conventional intersections. Results from raw data indicated that conventional intersections tended to have more head-on, left-turn, fatal-plus-injury, and property-damage-only accidents and relatively fewer rear-end accidents than NJJIs. These observations were confirmed by negative binomial crash prediction models that were developed to account for the influence of other causal factors. Models were estimated for total, fatal-plus-injury accidents, rear-end, and sideswipe accidents for both sets of intersections.
Road Sector Development in China and India
Authors: Seneviratne Prianka Nalin
Published: May 2018

India and China plan to pour billions of dollars into trunk road capacity and rural accessibility improvement projects over the next 15 years. However, there is concern about possible shortfalls in funding, largely because of competition from other sectors and numerous weaknesses in regulatory and control mechanisms in the road sector. Even if sufficient funds are available, inefficiencies in transport services and asset management are likely to return lower marginal rates on future investment. On the basis of a review of literature from the past 5 years, a case is outlined for further policy and strategy changes to maximize the benefits of investment in road assets. It is suggested that donors and governments should broaden support for the road sector to encompass transport services and traffic operations, with the aim of increasing productivity and decreasing negative externalities such as traffic accidents and vehicle emissions.
Innovative Design for Safe and Accessible Light Rail or Tram Stops Suitable for Streetcar-Style Conditions
Authors: Currie Graham , Smith Paul
Published: May 2018

Tram stops in streetcar environments present safety, accessibility, and transport efficiency challenges. With 245 km (152 mi) of track, Melbourne, Australia, has one of the world's largest tram systems. Some 68% is operated in streetcar conditions, and 1,200 of Melbourne's tram stops are curbside stops, where passengers wait at the curb. Road traffic stops when trams arrive so that passengers can get to and from trams operating in the center of mostly two-by-two-lane roads. Some 25 road accidents per year result because no pedestrian protection from traffic is provided. These stops have no platforms or lifts and thus act as a barrier to access by persons with disabilities. Providing platforms would be expensive and is not feasible in most cases. Passenger access also temporarily closes streets and causes traffic queues. Tram and road traffic speeds are reduced by 8% to 12% as a result. An alternative to tram stop design is clearly required. This paper describes a new tram stop design termed “the easy access stop.” The design incorporates a speed hump or cushion that serves as a platform to enable level boarding access to low-floor trams and that also slows passing traffic. The design has proved a cost-effective means of enabling safe tram stop access in streetcar-style conditions. The paper reviews international experience with streetcar-style stops and identifies the context for tram stop design. It describes the new design and outlines its effect and performance.
Picking up the Tab
Authors: Silkunas Steven
Published: May 2018

The emergence of light rail transit and other fixed-facility operations (including electric trolleybus and bus rapid transit) on public thorough-fares has grown substantially over the past 30 years. Few transit agencies, however, have sufficient internal policies to govern the disruption of fixed-facility operations. Further, few transit agencies have the experience that would allow them to abstract, for example, line loss from propulsion power. This paper establishes current practices in the United States and uses a case study example. The example illustrates that effective cost accounting can positively offset the disruption in service.
Spatial Decision Support System for Low-Income Families
Authors: Sriraj P. S. , Minor Mark , Thakuriah Piyushimita (Vonu)
Published: May 2018

Housing relocation or housing mobility is not uncommon in the United States, with the average family relocating once every 6 years. As part of this process, individuals and families take into account a variety of factors. One of the important factors is that of transportation and its availability. Various researchers have studied the impact of transportation information on relocation choice. However, the need for a structured methodology that incorporates various factors, such as transportation, has been highlighted from a study of the current practice of relocation counseling. The objectives of this paper are threefold: (a) to develop an analytical hierarchy process to rank census tracts for relocation purposes of individuals, (b) to present a prototype of the spatial decision support system (SDSS) with an example, and (c) to evaluate the impact of relocation choice of individuals by using a spatially unconstrained approach. With data from the six-county northeastern Illinois region, the SDSS is developed and showcased with the help of a sample application. Two scenarios are tested for each respondent. The first is based on only housing criteria, and the second compares all criteria in the analytical hierarchy process matrix with each other. The improvements in travel time determined from the results of the two scenarios are compared, and the results are discussed to highlight the salient features of the decision support system.
Infrastructure Asset Management Education
Authors: Smadi Omar , Akili Waddah
Published: May 2018

Asset management of civil infrastructure facilities and systems is gaining importance both in practice and in academia as the public demands increased accountability in government, laws are passed requiring infrastructure asset management, and growth and development accelerate the deterioration of already aged infrastructures. In response, more agencies continue to adopt and develop their asset management practices and more academic institutions and continuing education programs define courses and programs in civil infrastructure asset management. This paper focuses on an infrastructure management class offered at the graduate level mainly for civil engineering and transportation planning students. The outline of the class and a brief overview of active and engagement-based learning techniques are presented, and the way these techniques are integrated with the delivery of the asset management material is described.
Growth Forecasting of Vehicle Miles of Travel at County and Statewide Levels
Authors: Liu Feng , Kaiser Robert G. , Zekkos Michail , Allison Christopher
Published: May 2018

Growth forecasting of vehicle miles of travel (VMT) plays an important role in achieving a variety of goals and objectives in transportation planning, air quality planning and conformity analyses, and funding allocation for highway improvement programs. States have used a variety of methods to forecast statewide VMT growth, including historical growth factors, travel survey–based methods, and fuel consumption–based methods. The growth factor method appears to be the most popular technique. However, this method has a major limitation in that growth factors do not respond to changing socioeconomic conditions over time. In this study, statistical models were developed to forecast VMT growth at county, county aggregation, and statewide levels; these incorporated changing socioeconomic trends and forecasts for the future, as well as transportation system supply variables. During the modeling process, a variety of variables, different forms of these variables, and indices, including socioeconomics (population, households, employment, income), density and mix variables, lagged variables, difference form, and county dummy variables, were tested. Different types of regressions and model specifications were tested and evaluated for statistical validity and forecasting validity at county, county aggregation, and statewide levels. A selected set of models was used to forecast VMT for planning horizon years 2010, 2020, and 2030. Forecasting results were evaluated on the basis of forecasting trend versus historical trend, growth magnitude at state and county levels, and spatial patterns of growth. Finally, a preferred forecasting system was recommended for implementation. This study, a Pennsylvania case study, offers a VMT forecasting methodology that is low in cost and transferable to other states.
Photogrammetry Applications in Routine Bridge Inspection and Historic Bridge Documentation
Authors: Jáuregui David V. , Tian Yuan , Jiang Ruinian
Published: May 2018

This study explored the use of digital close-range photogrammetry for routine bridge inspection and historic bridge documentation. The major objective of the research was to evaluate the feasibility of photogrammetry for these two bridge engineering applications. Study results indicated that photogrammetry provides sufficient accuracy and is a noncontact, inexpensive, and practical measurement option. The research involved two photogrammetry projects. In the first project, photogrammetry techniques were employed in geometry measurement of a simple-span prestressed concrete bridge. The bridge was measured and evaluated according to routine bridge inspection guidelines. PhotoModeler, a consumer-grade photogrammetry software program, was used to process the images for measurements of vertical clearance, lateral clearance, deck width, and structure length. Comparison between photogrammetric and hand measurements showed minor differences, with the percentage error ranging from 0.06% to 1.43%. In the second project, a historic noncomposite, steel girder bridge was selected for documentation. Three-dimensional models of the bridge in elevation and of the pier were developed with PhotoModeler. Dimensions obtained from the models were compared with the design drawings, which showed that photogrammetry measurements differed by 0.23% to 8.00%. Two-dimensional, orthographic photographs (orthophotos) were also developed in PhotoModeler and edited with AutoCAD to provide scaled elevation drawings of the bridge.
Effect of Stay-in-Place Metal Forms on Performance of Concrete Bridge Decks
Authors: Guthrie W. Spencer , Frost Stephen L. , Birdsall Aimee W. , Linford Ellen T. , Ross Loren A. , Crane Rebecca A. , Eggett Dennis L.
Published: May 2018

The primary objective of this research was to investigate the effect of stay-in-place metal forms (SIPMFs) on corrosion of steel reinforcement in concrete bridge decks. The study included 12 concrete bridge decks located within the Interstate 215 corridor in the vicinity of Salt Lake City, Utah. All decks were subject to similar traffic loading, climatic conditions, and maintenance treatments, including applications of deicing salts during winter months, and had been constructed during 1984–1989 with epoxy-coated rebar. Test methods included visual inspection, chain dragging, hammer sounding, Schmidt hammer testing, half-cell potential testing, and chloride-concentration testing. An analysis of covariance (ANOCOVA) was performed to evaluate the effect of SIPMFs on each of the 13 deck properties measured. Five of the 13 analyses yielded significant results, including age, cover, Schmidt rebound number, half-cell potential, and chloride concentration at 2-in. depth. While differences in age and cover resulted from limitations associated with the deck selection process and were accounted for in the ANOCOVA, the differences in Schmidt rebound number, half-cell potential, and chloride concentration were attributed to elevated moisture contents in decks with SIPMFs. While higher moisture contents lead to enhanced curing conditions that ultimately provide higher concrete strengths, they also facilitate greater ionic current flow necessary to sustain higher reinforcement corrosion rates and cause accelerated diffusion of chlorides into the concrete. Given these findings, SIPMFs should be used with caution in concrete bridge deck construction.
Cooling Rates in Hot-Poured Bituminous Sealants
Authors: Collins Peter , Masson J.-F. , Al-Qadi Imad L.
Published: May 2018

The performance of bituminous sealants applied to cracks and joints is partly governed by installation. An important installation parameter yet to be investigated is the sealant rate of cooling after it is poured hot. Cooling rates affect sealant microstructure and rheology, adhesion at the sealant–hot-mix asphalt interface, and the time during which traffic must be rerouted. To provide data on sealant cooling rates, the temperature change in three sealants was measured in the field and in the laboratory. Results indicated that sealant bulk temperatures were >50°C lower than the sealant application temperature, typically 180°C, almost immediately after pouring, and that sealant bulk temperatures reached 40°C or less within 15 min. This finding suggests that traffic could be rerouted for less time than the standard 30 min. The instantaneous sealant temperature at the sealant–substrate interface was also measured to be below 100°C immediately after pouring of the sealant. This finding emphasizes the need for sealants with good wetting propensity to maximize the potential for proper adhesion.
Using Risk Analysis to Prioritize Intelligent Transport Systems
Authors: Johnston Kath , Ferreira Luis , Bunker Jonathan
Published: May 2018

With perpetual strains on resources, road agencies need to develop network-level decision-making frameworks to ensure optimum resource allocation. This is especially true for intelligent transport systems (ITS) and, in particular, variable message signs (VMSs), a key component of incident management services. The objective for VMSs is to minimize the safety, efficiency, reliability, and environmental impact of incidents on the operations of the transport system. This may be achieved by travelers being informed of the incidents so they can adapt their behavior in a manner that reduces community impact, such as lateness and the associated vehicle emissions, unreliability of travel times, and secondary accidents due to incidents. Generally, road authorities carry out needs assessments, but qualitatively in many cases. Therefore, a framework is presented that is systematic, quantitative, and relatively easy to implement. A risk management approach that focuses on minimizing the impact on and costs to the community was taken to prioritize VMS infrastructure deployment. In the presented framework and case study, safety, efficiency, reliability, and environmental effects are quantified by using an economic risk management approach to determine an overall risk score. This score can be used to rank road sections within the network, indicating the road sections with the highest risk of incident network impact and therefore the road sections with the highest need for intervention. A cost-effectiveness-based risk reduction ranking can then be determined for VMS, with the net risk with treatment being compared with that without treatment, and the net present value of deployment being divided. The two types of ranking, pure risk and cost-effectiveness–based risk reduction, will help to minimize the network impact on the community and optimize resource allocation.
Developments and Applications of Simulation-Based Online Travel Time Prediction System
Authors: Liu Ying , Lin Pei-Wei , Lai Xiaorong , Chang Gang-Len , Marquess Alvin
Published: May 2018

The framework and field application of a simulation-based online system for travel time prediction are presented. The proposed system is designed to contend with most critical issues associated with real-time operations, which include estimation of missing volumes, detection of incidents, data filtering, and computation of traffic volumes for projected time intervals so as to activate the simulation function. The proposed system was deployed on two routes of 30 mi between Salisbury and Ocean City, Maryland, with a total of 10 detectors. The preliminary application results clearly indicate that with proper integration the proposed system offers a cost-effective tool for real-time travel time prediction.
Flashing Message Features on Changeable Message Signs
Authors: Dudek Conrad L. , Schrock Steven D. , Ullman Gerald L. , Chrysler Susan T.
Published: May 2018

Studies were conducted with a driving simulator to determine the effects of displaying changeable-message-sign messages with dynamic features consisting of (a) flashing all lines simultaneously in a one-phase, three-line message and (b) flashing one line (top line) of a one-phase, three-line message. In the first dynamic feature, all three lines were flashed. Only the top line was flashed for the second dynamic feature. Messages with these two dynamic features were compared with comparable static messages. No differences in average reading time were found between the messages in which all three lines flashed and static messages. However, the results suggest that flashing an entire one-phase message may have adverse effects on message understanding for drivers who are unfamiliar with this dynamic mode of display. A significant percentage of the subjects preferred the static display. The average reading time for the flashing line (top line) messages was significantly longer than for the static messages. The results also suggest that unfamiliar drivers will be adversely affected by this particular display feature, relative to comprehension of the entire message. The subjects liked the flashing line and static messages equally well. No differences were found by age, education, and gender among the three dynamic message modes and their alternatives. In addition, no differences were noticed in driving performance.
Alternating Passing Lane Lengths
Authors: Gattis J. L. , Bhave Ranjit , Duncan Lynette K.
Published: May 2018

This paper reports on a study of passing lane operations, with a focus on continuous three-lane cross sections with alternating passing lanes (three-lane alternate passing or 2+1) segments in Arkansas. The examined aspects include effects of passing lane length on platooning, passing, speed, and passing lane crash rates. Five sets of field data were collected at four rural sites. After a vehicle entered the passing lane, platooning decreased and eventually stabilized. Passing activity was greatest at the beginning of the segments. Speed patterns were found to vary among sites, but average speed rose when a vehicle entered the passing lane section. Five years of crash data from 19 sites were used. Even though the volumes for the passing lane segments were higher than the state average volume for rural two-lane roads, the passing lane crash rates were generally lower than the statewide average crash rate for rural two-lane roads.
Operation and Safety of Right-Turn Lane Designs
Authors: Fitzpatrick Kay , Schneider William H. , Park Eun Sug
Published: May 2018

The objectives of this research by the Texas Department of Transportation were to determine the variables that affect the speeds of free-flow turning vehicles in an exclusive right-turn lane and explore the safety experience of different right-turn lane designs. The evaluations found that the variables affecting the turning speed at an exclusive right-turn lane include type of channelization present (either lane line or raised island), lane length, and corner radius. Variables that affect the turning speed at an exclusive right-turn lane with island design include (a) radius, lane length, and island size at the beginning of the turn and (b) corner radius, lane length, and turning-roadway width near the middle of the turn. Researchers for a Georgia study concluded that treatments that had the highest number of crashes were right-turn lanes with raised islands. This type of intersection had the second highest number of crashes of the treatments evaluated in Texas. In both studies, the “shared through with right lane combination” had the lowest number of crashes. These findings need to be verified through use of a larger, more comprehensive study that includes right-turning volume.
Modeling Shipper Response to Scheduled Waterway Lock Closures
Authors: Wang Shiaaulir , Tao Xianding , Schonfeld Paul
Published: May 2018

Scheduled preventive maintenance is required to preserve waterway locks and ensure satisfactory service in waterway operations. Because delays to waterway users usually increase during periods of lock maintenance, shippers may change departure times or switch to a different transportation mode. The analysis of variations in waterway traffic due to lock maintenance is a challenging task. This paper analyzes the cost structures of waterway and rail transportation and develops three waterway demand models on the basis of different user behavior assumptions. Numerical testing is conducted to verify the models. The results of the analyses show that these models, grounded in economics, traffic flow theory, and queuing models, can capture the effects of demand changes over time.