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The Ministry of Transportation of Ontario was interested in a rehabilitation strategy that could be used to address deep-seated rutting issues encountered on its 400-series highways. A precast concrete inlay panel (PCIP) rehabilitation design was developed and constructed involving the installation of precast panels into partially-milled asphalt pavement. Sub- surface instrumentation was installed at the PCIP-asphalt interface including earth pressure cells and moisture sensors installed in six instrumentation clusters. This instrumentation has been monitored to gather information regarding the PCIP trial installation. Readings from the moisture sensors indicate that water penetrates beneath the PCIPs in precipitation events, though these moisture levels recede under dry conditions, indicating that the water can exit the sub-slab area. Static load testing using a fully-loaded gravel truck was used to determine the different support reactions caused by different loading configurations. Higher loads were generally found beneath the joints in the two loading situations studied. Le ministere des Transports de l'Ontario s'est penche sur une strategie de refection qui pourrait etre utilisee pour regler les problemes d'ornierage profondement enracines sur ses routes de la serie 400. La conception pour la refection au moyen de panneaux d'incrustation en beton prefabrique (PIBP) a ete developpee et realisee par l'installation de panneaux prefabriques dans un revetement d'asphalte partiellement broye. Une instrumentation enfouie a ete installee a l'interface PIBP- asphalte y compris des cellules manometriques et des sondes d'humidite installees en six regroupements d'instrumentation. Cette instrumentation a fait l'objet d'un controle afin de rassembler des informations quant a l'installation des PIBP d'essai. Les lectures des sondes d'humidite indiquent que l'eau penetre au-dessous des PIBP lors d'evenements de precipitation, quoique ces niveaux d'humidite s'estompent dans des conditions seches, indiquant que l'eau s'evacue de la zone sous les dalles. On a eu recours a un essai de charge statique avec un camion de gravier charge a capacite afin de determiner, au niveau de la portance, les diverses reactions causees par differentes configurations de chargement. Les charges plus elevees se trouvaient generalement au- dessous des joints dans les deux situations de chargement etudiees. [Traduit par la Redaction] Mots-cles : beton prefabrique, refection des chaussees, panneau de beton prefabrique incruste, reparation de routes a forte circulation., Introduction Precast concrete panels (PCPs) have been used as a paving material since as early as 1931 in the Soviet Union (Rollings and Chou 1981); however, their use has only [...]

Producing as-built drawings is an important task in any road construction project. In fact, in an ideal situation, these drawings must be updated whenever major maintenance work takes place. Unfortunately, constantly updating those drawings is not always feasible due to the amount of manual work associated with the data collection in traditional surveying practice. The increase in computing power and the advancement in technology has led many transportation agencies to consider utilizing remote sensing techniques to extract roadway design features and prepare as- builts of roads. In this note, a procedure to generate as-built drawings of vertical profiles on highways using light detection and ranging (LiDAR) point cloud data are proposed. The procedure is a multistep procedure where the road centerline of each segment is first defined, after that a best fit alignment of points along the road's centerline is generated. A digital surface model (DSM) of the LiDAR highway is created and the centerline is relayed onto the DSM before generating the road profile. The proposed method is tested using LiDAR data collected on two highways in the province of Alberta, Canada. The profiles extracted using the proposed method are compared against vertical profiles that were generated for the same segments using data collected in GPS surveys and as-built drawings developed in manual surveys. The results show the feasibility of accurately extracting road profiles from LiDAR data. The average difference in grades estimated using the proposed method and the GPS data ranged from 0.023% to 0.061%. In fact, the proposed method was able to capture details in the road profile that were not detected using GPS data, demonstrating the value of using LiDAR for road profile extraction. Key words: remote sensing, light detection and ranging (LiDAR), LiDAR data, road profile extraction, vertical grade, as-built drawings, point cloud data. La realisation de dessins d'ouvrage fini constitue une tache importante pour tout projet de construction de route. En fait, dans un monde ideal, ces dessins doivent etre mis a jour chaque fois qu'un travail d'entretien majeur a lieu. Malheureusement, il n'est pas toujours faisable de mettre ces dessins a jour en raison de la charge importante de travail manuel associe a la collecte de donnees dans la pratique d'arpentage traditionnelle. L'augmentation de puissance de traitement et l'avancement de la technologie ont pousse beaucoup d'agences de transport a envisager d'adopter des techniques de teledetection pour extraire les caracteristiques nominales de chaussee et preparer l'etat definitif des routes. Dans le cadre de cette etude, on propose une procedure de realisation des dessins de l'etat definitif des profils verticaux des routes en utilisant les donnees de nuage de points obtenues par teledetection et telemetrie par ondes lumineuses (LiDAR). La procedure se deroule en plusieurs etapes ou la ligne mediane de route de chaque segment est d'abord definie, apres cela une droite de meilleur ajustement de points le long de la ligne mediane de la route est produite. Un modele de surface numerique (MSN) de la route LiDAR est cree et la ligne mediane est calquee dans le MSN avant de generer le profil de route. La methode proposee est testee utilisant des donnees LiDAR recueillies sur deux routes dans la province d'Alberta au Canada. Les profils extraits utilisant la methode proposee sont compares aux profils verticaux produits pour les memes segments utilisant des donnees recueillies lors de leves GPS et des dessins d'ouvrage fini developpes a partir de donnees d'arpentage. Les resultats indiquent la faisabilite d'extraire avec precision les profils de route a partir de donnees LiDAR. La difference moyenne des niveaux estimes en utilisant la methode proposee et les donnees GPS s'echelonnait de 0,023 a 0,061%. En fait, la methode proposee a pu saisir des details du profil de route qui n'ont pas ete detectes en utilisant des donnees GPS, ce qui demontre la valeur d'utiliser LiDAR aux fins d'extraction de profils de route. [Traduit par la Redaction] Mots-cles: teledetection, detection et telemetrie par ondes lumineuses (LiDAR), donnees LiDAR, extraction du profil de la route, niveau vertical, dessin d'ouvrage fini, donnees de nuage de points., Introduction Developing as-built drawings on a highway is a tedious process that is time consuming and labour intensive. This is particularly true when considering the size of Canada's roadway network, [...]

Modern proactive control algorithms can perform real-time traffic state prediction and help determine control plans for active traffic control measures, such as ramp metering (RM) and variable speed limit (VSL). In this study, a control algorithm, DynaTAM (Dynamic Analysis Tool for Active Traffic Demand Management), is proposed for prediction-based, integrated optimization control. DynaTAM considers the correlations between the implemented control measures and determines the control plan for both RM and VSL at the same stage of optimization. The algorithm framework possesses a candidate control plan generator, which reduces the computational load of future optimizations and eliminates much of the uncertainty in the system performance. A field-data-based simulation study with different control scenarios is conducted to evaluate the performance of DynaTAM. The DynaTAM control algorithm is shown to not only effectively perform integrated and coordinated control using both RM and VSL, but also significantly improve the efficiency of traffic operations during peak hours. Key words: ramp metering, VSL, ATM, proactive traffic control, integrated and coordinated control. Les algorithmes modernes de controle proactif peuvent realiser des previsions de l'etat de la circulation en temps reel et aider a determiner des plans de controle pour des mesures actives de controle de la circulation; ces algorithmes comprennent la regulation de bretelles d'acces (RM) et la limite de vitesse variable (VSL). Dans cette etude, un algorithme de controle, DynaTAM (Dynamic Analysis Tool for Active Traffic Demand Management), est propose pour le controle de l'optimisation integree base sur les previsions. DynaTAM tient compte des correlations entre les mesures de controles implantees et determine le plan de controle pour la RM et la VSL a la meme etape d'optimisation. Le cadre de l'algorithme presente un generateur de plans de controle admissibles, ce qui reduit la charge de calcul des optimisations futures et elimine une grande partie de l'incertitude quant au rendement du systeme. Une etude de simulation basee sur les donnees de terrain comportant plusieurs scenarios de controle, est realisee pour evaluer le rendement de DynaTAM. L'algorithme de controle DynaTAM non seulement realise un controle integre et coordonnee de maniere efficace en utilisant RM et VSL, mais ameliore grandement l'efficacite des operations de circulation durant les heures de pointe. [Traduit par la Redaction] Mots-cles: regulation des bretelles d'acces, VSL, ATM, controle de circulation proactif, controle integre et coordonne., 1. Introduction There is a rapidly increasing number of vehicles on roadways, contributing to serious traffic problems around the world each day. In particular, daily, recurrent freeway congestion leads to [...]

The Boussinesq theory for the distribution of stresses in a half-space resulting from surface loads is largely used in road engineering. It is based on the assumption of linear-elastic homogeneous isotropic half-space for the soil media. Since the soil exhibits nonlinear and irreversible behavior, it is of major interest to study the validity of this theory for nonlinear response of soils. This paper investigates this issue by comparing the elastic stress distribution to that obtained using respectively nonlinear elastic and elastoplastic finite difference analyses. Results show that nonlinear elasticity does not influence significantly the stress distribution while plasticity reduces the attenuation of the vertical stress in the soil mass, which means that Boussinesq solution underestimates the stresses in an area which contributes to the soil settlement. An important discrepancy is also observed in horizontal stress for the case of homogeneous and multilayered soil when plasticity is considered. CE Database subject headings: Boussinesq equations; Finite difference method: Layered soils; Elasticity; Numerical models; Plasticity; Stress distribution. Author keywords: Boussinesq solution; Finite difference; Multi-layered soil; Nonlinear elasticity; Numerical modeling; Plasticity; Road engineering. DOI: 10.1061/(ASCE)TE.1943-5436.0000084

Rutting has an adverse effect on safety and riding comfort of pavement. Reliable prevention and prediction of rutting has been one of the major focuses in road research. This paper summarizes the methods available for rut depth prediction and performs a case study in two separate ways based on the data acquired from a full-scale indoor circular road test. One was to formulate the possible rut depth by integrating a four-element-five-parameter viscoelastic model and the layered strain approach. The other was based on an empirical method. It is verified that both methods are applicable in predicting rut depth within the near future after open to traffic. The empirical method, however, is also capable of predicting rut depth within the whole design life. And theoretical method proves inadequate because of the limitation of the model itself and also of the method for obtaining parameters. CE Database subject headings: Asphalt pavements; Full-scale tests; Parameters; Statistics; Viscoelasticity; Rheology; Predictions.

In this paper a new method is proposed to analyze the mechanical response of a linear viscoelastic pavement. The material parameters of the asphalt concrete are characterized by the relaxation modulus and creep compliance, which are further represented by the Prony series. By virtue of the Laplace transform and the correspondence principle, the solution in the Laplace domain is first derived. The interconversion between the relaxation modulus and creep compliance is then applied to treat the complicated inverse Laplace transform. The displacement, strain, and stress fields are represented concisely in terms of the convolution integral in the time domain, which is subsequently solved analytically. Therefore, responses of the viscoelastic pavement are finally expressed analytically in the time domain and numerically in space domain, called a semianalytical approach. Since both the relaxation modulus and creep compliance are used simultaneously, instead of only one parameter in the conventional methods, the present method is also called a dual-parameter method. The present formulation is verified at both the short- and long-term time limits analytically and at the other finite time numerically, as compared to the conventional numerical methods. We clearly show that the present dual-parameter and semianalytical method can predict accurately the time-dependent responses of the viscoelastic pavement, especially at the long-term time. The present formulation could also be employed to validate the widely used collocation method. CE Database subject headings: Flexible pavements; Viscoelasticity; Layered systems; Analytical techniques.

Subgrade soil characterization in terms of resilient modulus ([M.sub.R]) is essential for pavement design/evaluation. Due to the complexity of the laboratory [M.sub.R] test procedure, highway agencies have been exploring nondestructive tests, such as the falling weight deflectometer. In this study, 12 test sections with subgrade reflecting a range of soil types (fine- and coarse-grain soils) were tested. Falling weight deflector measurements were conducted directly on the prepared subgrade, followed by thin-wall Shelby tube samples from depths up to 1.5 m for laboratory [M.sub.R] tests. Deflection measurements were repeated at the same locations after completion of pavement construction. Results showed that the back calculated moduli of the prepared subgrade are in good agreement with the laboratory values. Due primarily to confinement and overburden pressure, the backcalculated subgrade modulus, based on deflection measurements on the finished pavement, increases approximately 40 and 100% for fine- and coarse-grain soil, respectively. The modulus increase is substantiated by complementary studies of 20 Mississippi long-term pavement performance sections. In light of these results, the AASHTO factor of 0.33 to adjust for the backcalculated moduli, computed from deflection measurements on finished pavements, warrants further scrutiny and revision. CE Database keywords: Falling bodies; Weight; Nondestructive tests; Pavement design; Subgrades.

The Environmental Protection Agency and the Department of Transportation have launched a program to incorporate compost in state and local road construction processes. Compost can be used as roadside filter berms and other erosion-control applications; the article also provides information on compost content specifications for such uses.

Current design practices in North America are based mainly on 2D analysis of the highway alignment and do not account for the operating speed adopted by drivers. A more accurate approach should consider the interaction among the horizontal alignment, vertical alignment, and cross section based on the predicted operating speed. By combining the operating speed models along with 3D sight distance and vehicle dynamics models, a practical application of this approach is presented using an 8-km segment of Highway 61 (Ontario, Canada). By comparing the profile of predicted operating speed to the profile of allowable speed, based on 3D sight distance and vehicle dynamics, the consistency or deficiency in the highway segment is identified. The paper demonstrates the applicability of the 3D models to real highway segments and their usefulness in evaluating the adequacy of new designs or roads already in service. As the difference between the 2D and 3D results is significant, the 2D analysis is proven to be inadequate for such an evaluation, and the need for a 3D analysis is evident. Also, field measurements show that the accuracy of operating speed models is considerably compromised on combined horizontal and vertical curves. Thus, the results indicate the need to develop operating speed models that account for the effect of combined alignments and nighttime driving.

In practice, the task of designing the vertical alignment of a highway is done manually by an experienced engineer. As a result, the work is both time and resource consuming and relies heavily on human expertise. This work presents a mathematical model that solves for a set of optimal highway vertical grades for a given horizontal alignment. In addition to construction costs, facts considered by this model include earthwork balance and traffic speed in both directions. Code requirements and design practice are also considered. A three-layered heuristic is developed to solve the model. In the first layer, a neighborhood search heuristic is used to determine the locations where grade can change. The second layer sets penalty terms for sections where speed is undesirable, and the third layer solves a mixed integer program that has very few or no 0-1 integer variables. Computational testing on a 2-km road segment shows that the model yields good solutions.

Flow-speed-density plots are widely used by transportation professionals. The traditional presentation of these plots can be misleading, especially when large data sets are used. An improved presentation is suggested and its advantages are discussed. DOI: 10.1061/(ASCE)0733-947X(2010)136:7(689) CE Database subject headings: Traffic speed; Traffic flow; Transportation management. Author keywords: Fundamental diagram; Data-ink usage.