Accurate acquisition of aggregate characteristics (shape, size and spatial position) is the basis for in-depth analysis of asphalt mixture grading, uniformity and surface texture. This paper proposes a modified recognition algorithm for loose asphalt mixtures based on digital image processing. The process first converts a True Color RGB image into a binary image during pre-processing. Then a Euclidean distance transform of the binary image is performed, which can be used to get the regional maximum value. In order to avoid over-segmentation caused by the traditional watershed algorithm, a modified watershed segmentation algorithm based on the extended-maxima transform is developed, effectively limiting the number of regional maximums to a reasonable range. Then the watershed ridge lines are superimposed on the original image. Hence, the aggregates are separated correctly, especially touching particles. Seventy images of untreated aggregates consisting of different particle sizes were tested. The results showed that the improved method could effectively segment the particles with accuracy as high as 98%. Finally, the proven methods are programmed and used to identify the particles of loose asphalt mixture. The results showed that the physical information of the loose asphalt mixture aggregates could be adequately recognized, and the accuracy is 96%, which is a solid foundation for the subsequent in-depth research.
Although sidewalks and trails act as the foundation infrastructure for active modes, they are often secondary concerns to many municipalities. With limited budgets and resources, there is often greater emphasis in focusing investment towards primary infrastructure (such as roadways and bridges), which are typically backed by greater operational information and condition investigations that are used justify the use of public funds. While the focus on main infrastructure is justified, this often leaves very little funding or consideration for secondary infrastructure like sidewalks and trails. This issue of limited funding for sidewalks and trails, combined with potential high public use yet limited background data, increases the risk of lawsuits from conditions like trip hazards. Such lawsuits can be quite costly to municipal agencies and detrimental to public perception of safety and mobility. These practices of minimum funding and high liability lead to an inconvenient truth - sidewalks and trails carry a high level of liability and many agencies are not focusing on them enough. One reason for the omission in funding and priority is that municipalities struggle with how to approach condition rating their sidewalk and trail networks. There can even come a point where only condition rating the network is not enough. Simply put, this situation can place agencies in a position of having the data and being unable to use it effectively. To address these problems, the City of St. Albert set out to not only develop an acceptable condition rating system, but to also work closely with its GIS and IT departments on how to best represent it. This resulted in a network level condition rating which allows the city to have its sidewalk network represented in 10 m sections, all condition rated in a range of 1 to 5, 1 being “good condition”, 5 being “poor condition”. This system has allowed the City to better coordinate capital funding to ensure that as much work is accomplished in approved capital programming while being responsible with tax funds in complete transparency.
Shoreline erosion and relative sea level rise are increasing the risk of flooding and storm damage to Highway 2 as it approaches the Town of Souris. Climate change with the associated rising sea levels, reduced ice cover and changing storm patterns threaten to exacerbate this problem. In order to improve protection of the PEI portion of the Trans-Canada Highway (Hwy 2), PEI Transportation Infrastructure and Energy (PEI-TIE) worked with Coldwater Consulting Ltd. to develop and construct a two-part shore protection scheme that combined hard protection for the highway infrastructure with beach restoration works that would improve the resilience of the beach and dune system: 1. A timber/piled seawall was constructed parallel to Highway 2. This seawall allows for protection of the highway, while also extending the existing promenade along the top of the seawall. The wall was set back from the beach face to allow adequate space for beach restoration; 2. Dune restoration and shoreline stabilization works were undertaken to restore and strengthen the existing sand beach – dune system. The beach restoration works included the construction of two inter-tidal reefs. This is the first time that inter-tidal reefs have been used on the Island. An example of 'building with nature', the sandstone reef structures provide two primary functions: wave attenuation, dampening the effects of storm waves on the beach area and highway infrastructure; and, creating an area of calmer water on the landward side of the reefs where sand that is moving along the shore area will slow down and deposit and, over time, accumulate and cause the beach to grow / extend offshore towards the reefs.
More than 6.5 million tonnes of asphalt is used annually in the maintenance and construction of new roads in Ontario municipalities. The use of reclaimed asphalt pavement (RAP) in road construction has been proven to provide sustainable structures without affecting the integrity of virgin materials. Currently, in Ontario, only two-thirds of municipalities allow the use of RAP in the mix design of asphalt pavements, and most of those municipalities only use it in the base course layer. Promoting such sustainable approaches to infrastructure would lead to cost-effective spending on infrastructure, sustaining resources of virgin materials and would also result in limiting greenhouse gas emissions through reducing asphalt consumption and through utilizing locally available recycled materials. This paper aims to provide quantification of the current amount of RAP available in the province of Ontario, as well as provide trends of RAP consumption. An environmental scan of the province was conducted to obtain a database of RAP stockpile locations across Ontario. Volume measurements were conducted by using Google Earth Pro Software package. Additional calculations were conducted to estimate tonnage quantities of RAP. The RAP inventory and the trends of RAP consumption resulted from this study would help in the decision making for steering the infrastructure towards more sustainable use of available materials.
La Ville de Montréal (la Ville) possède et gère plus de 2 500 feux de circulation sur son territoire. Plusieurs systèmes simples et complexes sont actuellement en place actuellement afin de gérer dynamiquement les feux de circulation, par exemple des systèmes adaptatifs. Évidemment, les systèmes complexes sont performants, mais également plus dispendieux à l’achat, au déploiement et en frais de maintenance. Ils nécessitent habituellement de déployer des équipements de détection à toutes les approches d’une intersection à contrôler. Notre vision est de créer un système simplifié, moins coûteux et flexible. Ce système sera peut-être légèrement moins performant au départ, mais offrira plus de potentiel d’amélioration. L’approche de la Ville est d’utiliser une technique de gestion des feux de circulation existante, en l’occurrence le TRP (Traffic Responsive Plan), bien maîtrisée et d’y ajouter un volet de prédiction. En utilisant la prédiction des débits de circulation, on prévoit que les feux de circulation soient proactifs sur le trafic plutôt qu’en réaction à ce dernier. La technique de prédiction présentement utilisée est l’apprentissage machine et s’alimente à partir d’un flux de données temps-réel Internet des Objets (IdO) issu de plusieurs détecteurs véhiculaires. La technique d’apprentissage machine utilisée est eXtreme Gradient Boosting, XGBoost, (Chen & Guestrin, 2016) et sa performance est évaluée à l’aide de l’erreur moyenne absolue (mean absolute error, MAE). Nous présenterons les différentes phases du projet, l’étape à laquelle nous sommes rendus, ainsi que les différentes équipes impliquées à chaque étape. Sera aussi démontré le potentiel d’amélioration qu’apporte l’apprentissage machine en comparaison des autres techniques de gestion des feux de circulation.
In cold regions such as Canada, pavement structures are subject to extremely low air temperatures and seasonal freeze-thaw cycles over the life cycle of the roadway, resulting in pavement distress, deterioration, and decreased service life. Each year, billions of dollars are spent in Canada on rehabilitation and new construction of asphalt pavements. Hence, prevention of premature failure has become of prime strategic importance for road owners. Fibers have already been used to reinforce paving materials for many decades in various parts of the world. Polymer fibers have high tensile strength relative to asphalt mixtures, and thus, have the potential to improve the cohesive and tensile strength of bituminous mixes and prevent crack propagation in the resulting composite. The most commonly used polymer fibers are polyester, polypropylene, aramid, and various combinations of these. There has, however, been less attention to the incorporation of fibers in asphalt mixes to improve resistance to thermal cracking, an application that would prove extremely beneficial for road construction in cold climates. The objective of this research is to evaluate the effectiveness of adding polymer fibers to hot mix asphalt to increase its resistance to thermal cracking. For this purpose, three different types of polymer fibers including aramids, polyethylene terephthalate (PET) and polyacrylonitrile (PAN), in different sizes, were added to conventional hot asphalt mixes. The resulting samples were compacted in the laboratory and their mechanical properties were compared to conventional hot mix asphalt.
With rapid growth and development of urban cities, rural areas have become the primary location for industrial plants. Depending on the type of facility, major components may be fabricated at a facility far from the location of the industrial plant. The size and weight of these components during transport can significantly exceed typical roadway load limits. The secure and successful transport of the superheavy loads from the fabrication plant to the final location becomes a challenging endeavor. There have been multiple research attempts to develop structural response models to predict pavement damage from superheavy loads. This paper is an update to the 2016 TAC paper “Modelling Pavement Response to Superheavy Load Movement” in which the outcome of several studies of superheavy load moves planned for the spring and winter months was discussed. This paper expands the research on the transport of a super heavy load in winter. The transport of a Splitter from the Dacro Industries Inc. facility in Edmonton to the Inter Pipeline Propylene plant north of Scotford, Alberta was the heaviest-ever load on Alberta roads. The transport vehicle for the winter move comprised a double inter-combi trailer with a gross vehicle weight of approximately 1.5 million kilograms. This vehicle had two 24 axle line trailers with 1.5 m axle spacing. Due to the sophisticated nature of the project, and various shortcomings highlighted with previous research methods, non-linear dynamic finite element modelling (FEM) was used to determine the pavement layer stresses and strains when subjected to superheavy load moves. To facilitate the move, several trials were completed with various scenarios. The move was successfully completed on the first week of January 2019. This paper will summarize the methodology and results of various scenarios predicted and the pavement inspection result prior to and after the move.
Tack coats are thin applications of emulsified asphalt used to create an adhesive bond between asphalt layers, to allow for the creation of a monolithic structure as per pavement design requirements. The result is a “non-slip” structure comprised of fully-bonded pavement layers to distribute the traffic loads at an acceptable stress level to the subgrade. However, fully-bonded conditions may not necessarily be achieved during the pavement construction if the application rates are not optimized. This paper presents results of a 2018 field study conducted on a four-lane highway in the Province of New Brunswick. For this study, the maximum bond strength was determined by considering four tack coat spray rates in combination with two surface textures: milled surface and new asphalt mix. A section with no tack coat was also evaluated as a control section. Cores were subsequently collected following construction operations in order to determine the initial interlayer shear bond strength. An innovative “non-tracking” emulsion was used for this study as a tack coat for all the sections. Findings from this project will be used to provide recommendations and guidelines for optimum application rate, as well as construction best practices. This paper provides a summary of the field experiment and observations.
Nares River Bridge is located at km 105.2 on the Klondike Highway #2, Yukon, in the village of Carcross, and approximately 75 km south of Whitehorse. The existing Nares River Bridge was constructed in 1970 and consists of 17 trestle spans with a total span of 129 m. The bridge carries two traffic lanes of Klondike Highway #2 across the Nares River. The superstructure is comprised of longitudinal timber wearing planks on a transverse timber sub-deck. The substructure consists of steel trestles comprised of steel cap beams, pipe piles, and bracing. The ballast wall at the abutments uses staggered wooden planks. The southern part of the Klondike Highway is an important link in the Yukon highway system because it serves the mining, international commerce and tourism industries. The bridge is a vital piece of infrastructure because there is no other reasonable detour route for the transportation of goods and services between Yukon and the Skagway port. While the bridge remains safe for usage today, heavy haul loads are no longer permitted on account of compromised bridge capacity. Because of the importance of Nares River Bridge, inadequacy of the existing structure, and asset depreciation, the bridge has been prioritized for replacement. Highways and Public Works (HPW) is currently replacing Nares River Bridge at Carcross with a budget of $15 millions for the project over two years. The Nares River Bridge replacement project will provide Yukoners with a bigger and better bridge as part of Yukon’s highway network. Not only will this new asset ensure the South Klondike Highway is ready and able to meet future traffic demands and support the community of Carcross and the Carcross/Tagish First Nation, the project is also providing economic opportunities for Yukoners. For the first time on an infrastructure project of this nature, the Government of Yukon procurement process included a First Nation participation plan intended to address employment and training for Carcross/Tagish First Nation citizens and Carcross/Tagish First Nation firms. Many challenges were faced during the planning, consultation and procurement stages.
Connected vehicle technology consists of Vehicle-to-Vehicle (V2V) and Vehicle-to-Infrastructure (V2I) communication, collectively referred to as V2X. This enables vehicles and infrastructure to exchange safety related information to enable smarter, safer roads. If driver alerts are raised or automated action is taken as a result of these messages, it is critical that messages are trustworthy and reliable. To this end, the Security Credential Management System (SCMS) has been proposed to provide authentication and authorization of V2X messages without compromising individual privacy. A critical aspect of this system is the ability to identify and remove misbehaving devices from the network. This paper provides an overview the SCMS, proposed approaches to misbehavior management (or lack thereof), and some of the difficulties the SCMS is likely to encounter as it is more widely deployed.
Le présent article vise donc: Dresser un portrait sommaire de l’implantation de limite de vitesse 30 km/h au Québec et au Canada (état de la situation); Expliquer la différence entre une limite de vitesse de 30 km/h et une zone 30 km/h; Analyser l’impact sur le comportement des usagers (la vitesse pratiquée) de l’implantation de limites de vitesse de 30 km/h avec et sans mesures physiques- Il ne traite pas de l’aspect sécurité (réduction du nombre d’accidents); Présenter quelques bonnes pratiques en France et Angleterre; Et présenter certains constats généraux suite à cette étude.
The use of Lightweight Cellular Concrete (LCC) in the pavement structure is a potential solution to reducing the burden of the pavement on the roadbed, especially over weak soils, hence alleviating potential rutting and other forms of distress. Evaluating the performance feasibility of such materials is necessary, especially in comparison to traditional materials. This will involve both field and laboratory evaluation to provide relevant information for its application. As part of the field evaluation, a design that incorporated LCC as a subbase alternative in the pavement structure was developed and constructed. A shoulder bus stop which experienced severe rutting and cracking was selected as a trial location. The design of the trial included one control section constituting Granular B as subbase material and two LCC sections with LCC thicknesses of 250mm and 350mm as subbase material. Subsurface instrumentation was installed in each layer of the three sections including strain gauges, pressure cells, moisture probes, maturity sensors, and temperature strings. A weather station consisting of a rain gauge and solar radiation shield was also installed at the location of the trial section to monitor weather events. The instrumentation has been monitored to obtain information about the trial section with LCC and compare with the traditional Granular B material. Readings from the maturity sensors indicated that the concrete hydration process peaked at about twelve hours for both LCC sections and depicted a 28-day compressive strength of 1.67MPa and an ultimate strength estimated to reach 2.20MPa and 2.02MPa for the LCC 350 and 250 sections respectively. Temperature profiles indicated higher temperatures within and below the LCC layers compared to the control section, portraying LCC insulation properties. Moisture conditions were generally found to be saturated for all layers in all section during the preliminary study period. In general, data from all installed sensors including pressure cells and strain gauges, in addition to results already discussed are presented in this paper.
Long term pavement performance studies and continuous evaluations can help inform better rehabilitation strategies, thus suggesting more innovative rehabilitation designs. This research sought to answer questions on which overlay type would perform better overtime in wet-freeze regions, and what are the major factors influencing their performances. This paper addressed the performance of asphalt concrete over PCC pavements on four LTPP data sites in the selected wet-freeze climate locations of the US and Canada. It has been found that the performance of PCC pavements is subjected to different rehabilitation strategies in the GPS-7 section of the LTPP program. Initially, both convolutional and the modified asphalt overlay strategies were applied for the asphalt concrete pavements rehabilitations for both GPS-7B and C. Then, the performance comparisons are conducted. Firstly, the data obtained were analysed to evaluate the reduction in distresses and roughness index (IRI) achieved after these rehabilitation strategies were applied. Meanwhile, trend analyses were carried out to note the improvements overtime. It was found that the surface distresses such as longitudinal and transverse cracks took longer periods to occur on the modified overlays, and those defects have lower severity compared with the conventional asphalt overlays. What’s more, both types of overlay treatments resulted in similar levels of IRI after few successive years of service. However, the rate of roughness changing seemed better if the modified asphalt overlay was conducted on the milled surfaced and with thickness asphalt overlays. Finally, the scenarios generated for LCCA proved that modified asphalt overlays are more suggested than conventional asphalt overlay considering the overall pavement maintenance cost.
Traffic management is changing fast. In order to make the right choices concerning smart mobility, it is important for road operators to monitor ITS developments relevant for traffic management. Dutch road operator Rijkswaterstaat developed a so called Leading Innovation Timeline (LIT) to deal with this. It is a tool to visualize future innovation, more in particular changes in IT systems which are expected to have an impact on traffic management. The LIT helps create awareness of what is happening around us and how fast it will influence traffic management. When relying on the LIT, investments can be made in a timely manner. It also allows road operators to better assess risks of new innovations. The new LIT will be a European timeline However, broadening the timeline involves some challenges as the speed at which an innovation is implemented or accepted differs per country and depends on the systems already in place.
Efficient management of bridge structures requires a thorough understanding of the traffic using a bridge. In this paper an innovative static strain-based remote Bridge-Weigh-In-Motion (BWIM) system is deployed on a truss bridge in rural New Brunswick, Canada. The analysis methods are briefly outlined, and the system is successfully validated with a truck of known weight resulting in an average error of 7% in gross vehicle weight estimation. It is shown how the BWIM system can be used in estimating the dynamic amplification factors use in the analysis and design of bridges.
Recent watershed advancements in computer vision and machine learning has allowed for the possibility of classifying traffic characteristics from camera image data in real time. Information from traffic images can supplement data from other sensors such as loop detectors, Bluetooth and WiFi sensors and Dedicated Short Range communications (DSRC) roadside units. In this paper, we propose a method for near real-time estimation of traffic state variables such as volume and speed, in locations where traffic cameras exist. The proposed system allows municipalities and provinces to extend the utility of their existing camera systems with minimal additional resources. In this paper, we specifically explore the application of convolutional neural networks (CNN) to traffic image processing. We use existing loop detector data from Toronto highways as the ground truth to train and test the CNN to infer the macroscopic traffic flow characteristics of speed and flow from the still images. Preprocessing using temporal median stacking and image subtraction was first done to identify cars in lanes. The model was then trained, using ground truth data from loop detectors, to estimate traffic speed and volume directly from the images for all vehicle types. The proposed model generates promising results, with up to 88.6 percent accuracy, depending on the bin size.
An increased awareness of sustainability in the pavement industry has encourages the use of warm mix asphalt (WMA) technologies. Compared to conventional hot mix asphalt (HMA) that requires a high production temperature, WMA has several benefits, such as saving fuel and energy, reducing greenhouse gas emissions, and improving the work environment. However, systematic analysis of long-term field performance for pavements containing WMA mixtures has been scarce. Therefore, the objectives of this paper are to evaluate the field performance of flexible pavements using WMA technologies (referred as WMA pavements in this paper) and compare the general trends of the longer-term performance between WMA and HMA pavements across the United States. Specifically, 28 WMA pavement projects along with their companion HMA pavements were evaluated for an extended performance period in terms of transverse cracking, longitudinal cracking rutting, and moisture damage. A companion HMA pavement refers to a pavement that shares similar pavement structure, climate, traffic conditions and mixture design with the WMA pavement; the main differences are the usage of WMA technologies in the surface layer and the reduced production temperature for WMA mixtures. The selected projects include five projects constructed during the course of the study, and 23 in-service projects covering different service ages, traffic volumes, pavement structures, WMA technologies, amd four climatic zones across the United States. It was found that pavements containing various WMA technologies exhibited comparable long-term field performance as compared to that of the companion HMA pavement in terms of transverse cracking, wheel path longitudinal cracking, and rutting. No moisture-related distress was found in the field for either HMA or WMA pavements. Overall, cracking and rutting performance show a clear pattern of climate influence. Cracking distress appears to be more of a concern within wet climatic zones while less typical in dry climatic zones, which suggests that moisture should be considered in evaluating the cracking potential of asphalt mixtures. Results presented herein were part of NCHRP Project 9-49A on the Performance of WMA Technologies: Stage II – Long-Term Field Performance.
Due to the nature of construction, it is common for longitudinal joint in asphalt pavements to have lower densities and higher permeabilities than the main portion of the pavement lanes. To address this concern, many states employ joint treatments such as fog seals or void reducing asphalt membranes (VRAM). Qualitative evidence in Indiana appears to indicate that longitudinal joint lives have been improved using joint treatments, but the specific materials and application rates used to treat longitudinal joints in Indiana has not been qualitatively investigated. This research aims to investigate the fog seal materials and application rates specified for use on longitudinal joints and to compare the treatments. These objectives were accomplished by employing laboratory testing of both laboratory prepared specimens and field samples. The research performed on the laboratory specimens found the application of fog seals can improve the performance of the longitudinal joints with respect to permeability. While the permeability of the asphalt specimens was reduced by the presence of a fog seal treatment, the benefits were irrespective of the fog seal material. The results also indicate that the fog seal should be reapplied at five to seven year intervals. The testing of the field samples indicated that both the SS-1hfog seal and VRAM treatments were effective in reducing the permeability of the asphalt mixtures. The VRAM samples had statistically higher permeability coefficients than the SS-1h fog seal samples, which may be attributed to potential construction or material issues. While the SS-1h fog seal treatment appears to have better performance than the VRAM, the effectiveness of the treatments over time is not known. Additional further research is recommended to verify and support these results and recommendations and to further compare and understand the performance of SS-1h and VRAM treatments over time.
Located on the western edge of the City of Toronto, Pearson International Airport is Canada’s largest and busiest airport, moving over 41 million passengers each year on nearly 450,000 flights (Greater Toronto Airports Authority, 2017). The facilities at Pearson are immense, consisting of numerous check-in stations, security checkpoints, customs and border preclearance facilities, traveller amenities, and more, all spread across millions of square feet of space in two terminal buildings. Additionally, the airport serves as a temporary home to hundreds of aircraft, and a more permanent home to dozens of airside vehicles and the Link train that connects both terminals. Moreover, these facilities, services, and vehicles must all work together in a complex system to safely and efficiently move thousands of passengers every day. In this paper, an agent-based microsimulation model of Pearson Airport’s terminals is proposed, starting with an overview of the two terminals and their major components. Based on this information, sets of major classes and sub-classes are outlined, detailing their attributes and behaviours. Next, the relationships between these classes are described and the information flows that influence these relationships and behaviours are highlighted, including details about how the model steps through time. Finally, some sources of calibration and validation data are provided, and the airport’s interactions and relationships with other systems are explored. Using this model, it will be possible to gain a better understanding of Pearson Airport’s complex behaviours based on the behaviours of its numerous sub-systems.
Observation revealed that at the intersection of King Street and Yonge Street, streetcars blocked traffic seriously during green lights. To solve the problem, this report provides and evaluates two solutions, namely, streetcar platforms and Transit Signal Priority System. By comparing and analyzing, the superior solution, Transit Signal Priority System, is recommended in this report.