Showing papers by "Ontario Ministry of Transportation published in 2006"
TL;DR: Dutch travel survey data from a large sample of respondents is used to confirm previous research findings concerning the association between annual mileages driven and crash involvement.
331 citations
TL;DR: In this article, the state-of-the-art process-based model Delft3D Online Morphology has been used to generate synoptic data of high spatial and temporal resolution over the inlet domain.
88 citations
TL;DR: In this paper, the authors investigate the behavior of multileader stimuli, including insights into the number of vehicles ahead to which drivers react and the kind of stimuli to which they respond.
Abstract: This paper considers multianticipative car-following behavior (i.e., driver behavior that includes responses to multiple vehicles ahead). Two well-known models incorporating multivehicle stimuli (Bexelius and Lenz) are recalled, and various modifications are proposed to improve their performance. With vehicle trajectories for a motorway collected from a helicopter and a newly developed approach to parameter identification, new empirical evidence of multianticipative car-following is provided with estimates of the driver-specific parameters of the considered multianticipative car-following models. In doing so, one can investigate the nature of multileader stimuli, including insights into the number of vehicles ahead to which drivers react and the kind of stimuli to which drivers respond. Large interdriver variability in multileader driving behavior is also presented. In the last part of the paper, implications of the research findings for microscopic modeling are discussed.
80 citations
TL;DR: It is argued that SPMDs will generally yield more reliable estimates of exposure concentrations than mussels, because in situ BAF values are difficult to estimate, whereas the in situ exchange kinetics of SPMD can be quantified by measuring the dissipation rates of performance reference compounds.
Abstract: Concentrations of hydrophobic chemicals in mussels and semipermeable membrane devices (SPMDs) from nine studies published over the past decade, amended with new data obtained in the Scheldt−North Sea area, were assessed to understand the similarities and differences between these sampling matrixes. A model was developed to describe the concentration ratios, using literature values of elimination rate constants and steady-state accumulation factors of both samplers as key parameters. The model could successfully describe the results of seven studies. Differences in concentration ratios among these studies were related to the variability of mussel bioaccumulation factors (BAFs) and water sampling rates of SPMDs. For two studies, the model could only describe the data by adopting unrealistically high water sampling rates, and for one study there were not enough data to test the model. We argue that SPMDs will generally yield more reliable estimates of exposure concentrations than mussels, because in situ BAF...
71 citations
TL;DR: This is the first study that shows the singular and combined effects of several flooding characteristics on both presence, and species composition, of softwood and hardwood species from riparian woodlands.
69 citations
TL;DR: In this paper, the authors discuss the development in installation techniques, equipment and materials, and the corresponding institutional changes that were needed to keep up with these changing demands, under climatic, physical and social conditions that differ from the ones for which they have been designed.
68 citations
TL;DR: In this article, the theoretical backgrounds and mathematical descriptions of reinforcement corrosion with regard to a numerical modelling are presented and discussed, as well as the theoretical and mathematical description of the reinforcement corrosion.
Abstract: During recent years research projects with different approaches have been carried out to develop models which are suitable to assess the metal removal rate in case of reinforcement corrosion. Some of them are based on empirical methods and correlate the corrosion rate to parameters like concrete resistivity, temperature and relative humidity. Another type of model is based on a quantification of the ongoing electrochemical processes. In this paper the theoretical backgrounds and mathematical descriptions of reinforcement corrosion with regard to a numerical modelling are presented and discussed.
57 citations
TL;DR: In this article, an analysis of premature low-temperature cracking in three Ontario, Canada, pavements is documented and discussed, showing that reversible aging tendencies, as indicated by bending beam rheometer (BBR) tests after extended periods of conditioning, showed that although all three binders met the specification, they lost a considerable amount from their grade temperature according to AASHTO M320 criteria.
Abstract: An analysis of premature low-temperature cracking in three Ontario, Canada, pavements is documented and discussed. Two of the contracts consisted of a 50-mm single lift of hot-mix asphalt on recycled asphalt pavement; the third contract was a single lift overlay on a previously cracked pavement. All three pavements exhibited extensive transverse cracking during their first winter. The binders used in each of the surface courses were evaluated for possible deviations from specification requirements and for their susceptibility to cracking as a result of excessive reversible aging during cold storage. The reversible aging tendencies, as indicated by bending beam rheometer (BBR) tests after extended periods of conditioning, showed that although all three binders met the specification, they lost a considerable amount from their grade temperature as determined according to AASHTO M320 criteria. Fracture tests on the binders showed that properties in the brittle state were all considered to be poor, yet typical for unmodified materials. Fracture properties in the ductile state for the binder from the one overlay contract indicated that low resistance to ductile failure could explain the observed distress. The experience has further confirmed the need to develop an extended BBR test protocol as well as brittle and ductile fracture tests to exclude binders that will be susceptible to these types of failures for future paving contracts.
46 citations
TL;DR: In the Belonitor trial, DOT traffic safety objectives were successfully combined with profit goals of the lease company, and data obtained from surveys, interviews, and the in-car system indicate that feedback and rewards have a strong positive effect on safe driving behavior.
Abstract: The most important objective of the Department of Transport (DOT) in the Netherlands is to make Dutch freeways safer and less congested. To achieve these objectives, standard practice has been to influence the behavior of road users through punitive measures. To investigate the feasibility of doing the opposite, namely, influencing behavior by offering rewards, and of its usefulness if it worked, the DOT launched the Belonitor trial. Each year, tailgating and speeding cause much irritation on roadways. Moreover, these violations often play a role in accidents and congestion. The Belonitor trial therefore focuses on two preferred modes of behavior: maintaining sufficient distance and maintaining the applicable maximum speed. The lease company LeasePlan Nederland N.V. (LPNL) fitted 62 lease cars with equipment that recorded whether drivers maintained sufficient distance from the car ahead and drove within the posted speed limit. The equipment included a display that continuously showed drivers their following distance and speed. LPNL rewarded lease-car drivers for good driving behavior over a 16-week period. The data obtained from surveys, interviews, and the in-car system indicate that feedback and rewards have a strong positive effect on safe driving behavior. The trial results also indicated differences in how drivers handle speed and following distance. In the Belonitor trial, DOT traffic safety objectives were successfully combined with profit goals of the lease company.
45 citations
TL;DR: Observations suggest that trace metals are not immediately bound in an insoluble, inert form when they are in contact with sulphide, which has consequences for modelling metal processes in sediment, as well as for uptake by some biota.
44 citations
TL;DR: In this paper, the authors employed the directional graph distance function and the multiactivity data envelopment analysis (DEA) approach, which incorporates both desirable and undesirable outputs, to provide a more complete representation of the multimode bus production technology from which environmentally and risk-sensitive cost effectiveness measures can be generated.
Abstract: This study employs the directional graph distance function and the multiactivity data envelopment analysis (DEA) approach, which incorporates both desirable and undesirable outputs, in order to provide a more complete representation of the multimode bus production technology from which environmentally and risk-sensitive cost effectiveness measures can be generated. We treat accident cost as the risky output in the sense that we wish to increase desirable outputs and decrease risky output and inputs. The approach is applied to the problem of measuring the cost effectiveness of 24 bus companies in Taiwan. An empirical illustration suggests that the overall cost effectiveness rankings turn out to be very sensitive to whether or not the graph multiactivity DEA approach is adopted. This implies that the conventional DEA cost effectiveness measure may be seriously misleading if it ignores the cost effectiveness of organizations that carry out various activities whilst sharing common resources.
TL;DR: Because older drivers on average manage to reduce their risk per distance driven by choosing driving patterns that are safer than the driving patterns of other age groups, the risk of older drivers as a group is not overestimated.
TL;DR: In this paper, the authors present the various developments and their consequences with respect to flood management and present the divers developpements and leurs consequences en ce qui concerne la protection contre les inondations.
Abstract: An increasing proportion of the world's population is living and working in flood-prone areas. There are no indications that this tendency will change. In the rural areas we may observe improvements in agricultural production and an increase in the value of crops, farm buildings, water management facilities and infrastructure. In addition, due to urbanisation, industrialisation and improving standards of living, especially in the emerging countries, the value of property, buildings and infrastructure has significantly increased and will further increase in future. Especially in flood-prone areas in South and East Asia we may observe a very rapid growth of urban areas. In order to cope with this growth of new urban areas reclamation has very often taken place in nearby low-lying areas. From a flood protection and water management point of view this implies removal of storage areas and increase in urban drainage discharges. The paper presents the various developments and their consequences with respect to flood management. Copyright © 2006 John Wiley & Sons, Ltd.
Une proportion croissante de la population mondiale vit et travaille dans des zones a risque d'inondation. Et il n'y a aucune indication que cette tendance puisse changer. Dans les secteurs ruraux on peut observer des ameliorations de la production agricole et une augmentation de la valeur des recoltes, des bâtiments de ferme, ainsi que des equipements et infrastructure de gestion de l'eau. En outre, en raison de l'urbanisation, de l'industrialisation et de l'augmentation du niveau de vie, particulierement dans les pays emergents, la valeur des terres, des bâtiments et des infrastructures a sensiblement augmente et augmentera encore dans l'avenir. Particulierement dans des zones a risque de l'Asie du Sud et de l'Est on peut observer une croissance tres rapide des secteurs urbains. Afin de faire face a cette urbanisation croissante, des zones basses voisines ont souvent fait l'objet de rehabilitation. Du point de vue de la protection contre les inondations et de la gestion de l'eau, ceci implique le deplacement de la zone de stockage et l'augmentation des debits du drainage urbain. L'article presente ces divers developpements et leurs consequences en ce qui concerne la protection contre les inondations. Copyright © 2006 John Wiley & Sons, Ltd.
TL;DR: This paper investigates whether the willingness to pay based VOSL is higher or lower for children in New Zealand in 1997-1998 and shows that for the whole sample, the value is higher for children than for adults.
TL;DR: In this article, the authors analyzed the interrelations between gas formation and sediment physical, chemical and biological qualities, and found that the extent and amplitude of each phase varied strongly between sediment and could be correlated well with only a few standard analytical parameters, despite the strong heterogeneity of sediment with respect to chemical, physical, and biological characteristics.
Abstract: Under anoxic conditions typically prevailing in disposal sites for dredged sediment, methanogenesis is the terminal step during microbial degradation of sediment organic matter. Sediment gas production may pose several problems to site management and post-closure utilisation. Depending on the magnitude of gas/methane formation and the intended utilisation of the site, countermeasures will have to be effected during and after deposition of the dredged material. For this purpose it may be of interest to pre-estimate the extent of gas formation from simple sediment variables. Therefore, the aim of the investigations presented here was to analyse the interrelations between gas formation and sediment physical, chemical and biological qualities. Freshly sampled riverbed sediment from nine German federal waterways was analysed for standard solid physical and chemical parameters, pore water composition, cell counts of methanogenic and sulfate-reducing bacteria, and gas formation over a period of 500 days. Particle size and density fractionation were carried out in order to characterise organic matter quality. Correlations between methane formation and sediment chemical, physical and microbiological characteristics were tested using linear and multiple correlation analysis. The selected sediments, including two with marine influence, differed strongly regarding texture, chemical parameters, pore water composition, and methanogen cell counts. The course of methane formation was found to follow distinct phases. The commencement of methane formation was preceded by a lag phase of variable duration. The lag phase was followed by a strong increase of the methane formation rate up to a sediment-characteristic maximum of 5–30 nmol CH4 h–1 g dw–1. Eventually, the rate of methane formation decreased and reached a more stable, long-term level. The extent and amplitude of each phase varied strongly between sediments and could be correlated well with only a few standard analytical parameters, despite the strong heterogeneity of sediment with respect to chemical, physical, and biological characteristics. Lag phase duration depended strongly on the content of inorganic electron acceptors and also on the number of methanogens present at the beginning of the experiment. Maximum and steady state methanogenesis were mainly determined by sediment total nitrogen. As analysis of sediment density fractions revealed that total nitrogen reflected the share of readily degradable macroorganic matter. The results imply that the observed methane formation is a function of the temporally changing balance of the availability of electron acceptors and H2, and the share of easily degradable organic matter. For fresh riverbed sediments, the latter may be deduced from total nitrogen content. Overall, the results showed that methane formation by freshly dredged material may well be pre-estimated from standard analytical data within the first few years of deposition. However, the differently degradable organic matter pools will change over time with respect to size, chemical nature and association with the sediment mineral phase. It can thus be expected that the correlations found in this study will not be readily transferable to older materials. Further studies on the gas formation and organic matter quality by older sediments, e.g. from older dredged material disposal sites of known age, should be conducted and results should be combined with existing organic matter degradation models in order to improve the prediction of sediment gas formation over time.
TL;DR: In this article, the UHMWPE pads with a carbon fiber/epoxy reinforced ring are used as sliding material into the chairs of the structure, while the steel ball side is covered with a Zn-phosphate primer coating, protecting against corrosion.
TL;DR: In this paper, the planning philosophy and policy formulation of Taiwan's public transport development are highlighted, and the most important initiatives, including the Five-year Enhancement of Mass Transportation Program and the upgrading public transport schemes in the National Development Plan are examined.
Abstract: Over the past decade, the escalating roadway congestion and environmental deterioration due to heavy use of private vehicles have provoked the Taiwan government to realize the importance of public transport systems. Under the “carrot-and-stick” rationales, the government has formulated public transport policies and exercised a series of related initiatives by providing sufficient and higher quality of public transport services so as to attract more private vehicle users. In this paper, the planning philosophy and policy formulation of Taiwan’s public transport development are highlighted. The most important initiatives, including the Five-year Enhancement of Mass Transportation Program and the upgrading public transport schemes in the National Development Plan are examined. Based on previous experience and lessons, we point out the most challenging issues that the government will encounter. Suggestions for the future of public transport planning are also addressed.
TL;DR: This paper will address a number of pitfalls in probabilistic calculations by identifying the most critical model parameters and demonstrating the influence of statistical distribution of these parameters on the outcome.
Abstract: Designing for durability of reinforced concrete structures using a probabilistic approach is becoming increasingly popular among consultants. This paper will address a number of pitfalls in probabilistic calculations by identifying the most critical model parameters and demonstrating the influence of statistical distribution of these parameters on the outcome. Especially, the so-called age factor and critical chloride content play a dominant role in service life predictions. A procedure will be proposed to quantify these parameters from existing structures to achieve an improved prediction of residual service life. In addition, it will be demonstrated that probabilistic service life modelling may be misused by manipulation of the input values, shifting the risks for premature maintenance to the owner.
TL;DR: A population model developed for Corophium volutator, a marine amphipod used in sediment bioassays, provides new information about the sensitivity of test organisms and thus contributes to reducing uncertainty in test results, and provides a means to increase the ecological relevance of bioassay responses.
TL;DR: The results indicate that the age, size, and type of engine, and the manufacturers of motorcycles all play a significant role in determining I/M emission test results, and that two-stroke motorcycles emitted approximately ten times greater HC than those of four- stroke motorcycles.
TL;DR: In this paper, the authors implemented the Miles' theory to derive formulae for describing the Bragg scattering of water waves for doubly composite artificial bars with different shapes, spacings, relative bar heights and the number of bars.
TL;DR: In this article, a special session on the protection contre les inondations (ISFD3, Pays-Bas, 25-27 mai 2005) was organized for dirigeants d'organismes de gestion d'inondation dans 13 pays du monde.
Abstract: Dans le cadre du 3eme colloque international sur la protection contre les inondations (ISFD3, Pays-Bas, 25-27 mai 2005), une session speciale a ete organisee pour les dirigeants d'organismes de gestion d'inondation dans 13 pays du monde. Le but etait d'echanger leurs experiences de la pratique de gestion integree des inondations et de la gestion au jour le jour. Bien que ces pays different considerablement en ce qui concerne les problemes d'inondation qu'ils rencontrent ainsi qu'en matiere de socio-economie et d'organisation, quelques traits communs ont emerge: defi consistant a traduire une approche basee sur le risque a l'echelle d'un bassin en mesures concretes, responsabilite et conscience du risque d'inondation, harmonisation de la gestion des risques d'inondation avec la planification d'occupation de l'espace, cooperation institutionnelle, et confrontation a des budgets de maintenance insuffisants. La session speciale s'est conclue sur des recommandations pour la gestion et la recherche. Cet article presente les principales discussions et conclusions de cette session.
TL;DR: In this article, the authors presented a costbenefit analysis to guide the development and implementation of a national smart card system in the Netherlands, which not only examined the overall potential impact but also appraised effects on different stakeholders under various scenarios.
Abstract: In the Netherlands, public transport plays an important role in meeting the public's travel demands. The country's 19 public transport authorities are required by the central government to implement innovative business practices. The primary objectives are to facilitate competition, improve efficiency, and increase ridership. Smart card technology is seen as a means of aiding in the liberalization of the market and providing management information for planning and marketing. The country's major urban and regional transport system operators agreed in November 1998 to work together to develop a national smart card system. The Dutch Transport Ministry commissioned a cost-benefit analysis to guide the development and implementation of the technology nationwide. The study not only examined the overall potential impact but also appraised effects on different stakeholders under various scenarios. In addition, sensitivity analyses were undertaken to enhance the study's robustness. The methodology used provided a ...
Journal Article•
TL;DR: In this article, the authors presented a literature survey of explosive spalling of concrete at elevated temperatures and summarized the affecting factors, mechanisms and the current theoretical and experimental studies, concluding that the coupling of thermal cracking and pore pressure is the main reason to induce the thermal spalling.
Abstract: This paper presented a literature survey of explosive spalling of concrete at elevated temperatures. The affecting factors, mechanisms and the current theoretical and experimental studies were summarized respectively. The investigations results show that the coupling of thermal cracking and pore pressure is the main reason to induce the thermal spalling and uncertainty of explosive spalling. The explosive spalling induced by elevated temperatures is a complex nonlinear problem, which can be understood very well only through establishing a theory system introducing both the material science theory and the mechanics theory.
TL;DR: In this paper, a viscous plus variable-friction damping force algorithm was proposed to combine advantageous features of typical viscous and friction dampers, which can be achieved with a good accuracy at the excitation frequency of 1 Hz.
Abstract: In this study, the preset damping force algorithm, called the viscous-plus-variable-friction damping force algorithm, was proposed to combine advantageous features of typical viscous and friction dampers. The proposed damping force algorithm can be represented by a viscous element placed in series with a variable-friction element. When the damping force reaches a peak value of the viscous element or a preset force limit, the sliding of the variable-friction element occurs, resulting in a constant damping force. The realization of the proposed damping force algorithm by a magnetorheological (MR) damper was investigated. It is found that the algorithm can be achieved with a good accuracy at the excitation frequency of 1 Hz. Then, a series of analyses was conducted on the based-isolated benchmark building controlled by the damping force algorithm. The benchmark building has eight storeys with elastomeric bearings at the base. The semi-active dampers whose damping forces are characterized by the proposed damping force algorithm are installed between the base and the foundation. The investigation was done on seven ground motion records. From the analysis, it is found that with use of the damping force algorithm the base displacement can be reduced by 20–50%. The floor acceleration increases by 20% in some ground motion records. Copyright © 2005 John Wiley & Sons, Ltd.
TL;DR: In this article, the performance of sensor-and image-based pavement condition assessment was compared and a data management plan was created to allow efficient data manipulation, and advanced analysis of variance was performed to allow statistical data comparisons among companies and among automated technologies.
Abstract: Even though companies that assess pavement condition compete to innovate by providing better software for automatic analysis and diagnosis, the industry as a whole remains limited, and data collection and storage methods are disparate. In fact, software and handling procedures are proprietary—each vendor has its own automated technology to detect, classify, and quantify surface distresses. In a research effort sponsored by the Ministry of Transportation of Ontario, Canada, the performance of sensor- and image-based pavement condition assessment was compared. First, a data management plan was created to allow efficient data manipulation. Second, a suitable set of similar distresses was selected as response variables of interest to design and conduct statistical experiments. Third, advanced analysis of variance was performed to allow statistical data comparisons among companies and among automated technologies. Finally, results were discussed and recommendations made. Overall, service provider measurements ...
TL;DR: It is argued that validation of the model will not solve the problem that decision makers deal with, and that although invalidated, decision makers can use the model results by using them as early warning signals.
TL;DR: In this paper, the authors deal with prevention of human errors by proper road planning, road design, and improvement of existing roads within the framework of the Dutch sustainable safety vision, focusing on three design principles for road networks and for roads and streets: functionality, homogeneity, and predictability.
Abstract: This paper deals with prevention of human errors by proper road planning, road design, and improvement of existing roads within the framework of the Dutch Sustainable Safety vision. This vision focuses on three design principles for road networks and for roads and streets: functionality, homogeneity, and predictability. The ambition is to reduce considerably the number of crashes and casualties and maintain the Netherlands as one of the countries with the best road safety records. This vision was launched at the beginning of the 1990s and accepted as a formal part of Dutch policies in the mid-1990s. It resulted in a so-called Start-Up Program on Sustainable Safety, not only addressing the planning and design of road infrastructure but strongly emphasizing those aspects. Contents of the start-up program are described as the process leading to implementation. An overview presents different (road infrastructure) components of the start-up program and the estimated effects on road crashes. These components ar...
01 Mar 2006
TL;DR: In this paper, a new statistical extrapolation method based on Bayesian approach, that takes account of statistical uncertainties, is proposed to provide a better physical basis about the catchment response under extreme meteorological circumstances.
Abstract: In the Netherlands, the design discharge for the river Rhine may be exceeded on average once every 1250 years. Design discharges are currently estimated by fitting of probability distributions and extrapolation techniques. To this aim, reliable and homogeneous observations are needed. Unfortunately, time series of observed discharges are of a limited length. Consequently, different probability distributions lead to quite different extrapolated values, and the goodness-of-fit tests to select an appropriate probability distribution are usually inconclusive. The fact that the series of observations are short and physical knowledge about the catchment response is not included in this analysis, contributes to this inconclusiveness. Therefore, in the Netherlands, new methodologies are investigated. The new developments consist on one hand of a new statistical extrapolation method based on Bayesian approach, that takes account of statistical uncertainties. On the other hand, a methodology is being made to provide a better physical basis about the catchment response under extreme meteorological circumstances. This method consists of a statistical rainfall generator combined with hydrological and hydraulic models. Together with the current extrapolation method, these new developments are the subject of this paper.
TL;DR: In this article, a combined numerical- experimental analysis was applied for design improvement with a representative small-scale qualification test on the real ring geometry, inducing additional stress concentrations compared to ASTM standards.
Abstract: Carbon fibre/epoxy rings are used as radial reinforcement for polymer bearing elements with nominal diameter 250 mm functioning under 150 MPa. Full- scale static and dynamic testing revealed no catastrophic failure for loading to 400 MPa, although there was circumferential splitting of carbon fibres at the machined top edge causing counterface wear under sliding. A combined numerical- experimental analysis was applied for design improvement with a representative small-scale qualification test on the real ring geometry, inducing additional stress concentrations compared to ASTM standards. Full-scale modelling revealed high radial-axial shear stresses (33 MPa) in non-hydrostatically loaded zones, while it increased towards 104 MPa under hydrostatic load conditions. The former is the most critical and should be simulated either on a small-scale unidirectional com- pression test or on a representative short beam shear test, respectively, measuring the radial-axial or radial-tangential shear strength. A relation between both small- scale states of stress was experimentally and numerically studied, experiencing that the composite ring has lower radial-tangential shear stress compared to radial-axial shear stress as a different hydrostatic stress state is observed in the bulk of the composite ring. As a compressive test is however more difficult to perform than a short-beam-shear test, a representative design criterion for shear fracture is determined from failure at 27 kN normal load in a short-beam-shear test. Finally,