• Transport Research

Methodologies to model the impact of ramp metering queues on diamond interchange operations were developed in this study. The methodologies are part of an overall research effort to address the integrated operations of a diamond interchange and a ramp metering system. The methodologies were implemented in DRIVE, a computer model characterized as a mesoscopic simulation and analytical model. A meso-scopic model has the advantages of both macroscopic and microscopic models with less computing time while still considering stochastic traffic flows. DRIVE can be used to perform system analysis and evaluation of an integrated diamond interchange and ramp metering system over multiple cycles. The component concerning the diamond interchange operations is documented here, with a particular focus on the impact of potential queue spillback to the diamond interchange signals from ramp metering. The study focused on the two common diamond phasing schemes: basic three-phase and Texas Transportation Institute (TTI) four-phase. DRIVE was validated against the VISSIM microscopic traffic simulation model, and general agreement was found in the results between the two models. For oversaturated ramp conditions with queue spillback, both DRIVE and VISSIM indicated that TTI four-phase favors the frontage road approach, whereas the basic three-phase favors the arterial left-turn movement. DRIVE provides a new analysis tool for analyzing diamond interchange operations taking ramp metering into consideration, which would facilitate studies on developing operational strategies to better manage such systems.

Many authors have questioned the abilities of the automotive industry to design new eco-friendly vehicles (Beaume and Midler, 2009; Calabrese, 2012; Freyssenet 2009, 2011). Experiments as Bluecar and Autolib in Paris are giving signs that certain projects are oriented toward sustainable targets. The Bluecar and Autolib, an electric car sharing system, is the outgrowth of an historical process. Instead of studying this system of mobility as an innovation in its final state, this article analyses this sharing system as a product service process (Manzini and Vezzoli, 2003). This paper discusses the issue of industrial design in the product development process for the automotive sector. Then it presents some iconic electric concept cars and the first trial rental sharing systems. Finally, the Bluecar and the Autolib electric car sharing system illustrate how the activities of the industrial designers were involved in the development process that ended in a new product and service.

AbstractFossil benthic foraminifera are used to trace past methane release linked to climate change. However, it is still debated whether isotopic signatures of living foraminifera from methane-charged sediments reflect incorporation of methane-derived carbon. A deeper understanding of isotopic signatures of living benthic foraminifera from methane-rich environments will help to improve reconstructions of methane release in the past and better predict the impact of future climate warming on methane seepage. Here, we present isotopic signatures (δ13C and δ18O) of foraminiferal calcite together with biogeochemical data from Arctic seep environments from c. 1200 m water depth, Vestnesa Ridge, 79° N, Fram Strait. Lowest δ13C values were recorded in shells of Melonis barleeanus, − 5.2‰ in live specimens and − 6.5‰ in empty shells, from sediments dominated by aerobic (MOx) and anaerobic oxidation of methane (AOM), respectively. Our data indicate that foraminifera actively incorporate methane-derived carbon when living in sediments with moderate seepage activity, while in sediments with high seepage activity the poisonous sulfidic environment leads to death of the foraminifera and an overgrowth of their empty shells by methane-derived authigenic carbonates. We propose that the incorporation of methane-derived carbon in living foraminifera occurs via feeding on methanotrophic bacteria and/or incorporation of ambient dissolved inorganic carbon.

Leakage detection is a crucial issue for factories with numerous pipelines and valves. Conventional methods for leakage detection are mainly rely on manual checking, which results in both high delay and low accuracy. In this paper, we propose TagLeak, a real-time and low-cost system for automatic leakage detection with commercial off-the-shelf (COTS) RFID devices. The key intuition behind TagLeak is that the leaked liquid around tags will change their phase and RSSI (Received Signal Strength Indicator) readings. Multiple challenges need to be addressed before we can turn the idea into a functional system, including: i) it is difficult to detect the slight signal variation that caused by the leaked liquid, based on the coarse-grained RSSI sequence; ii) multipath and interferences can undermine the tags signal, making the variation caused by leaked liquid more difficult to detect. We propose solutions to these challenges and evaluate the systems performance in different environments. The experimental results tell that TagLeak achieves a higher than 90.2% true positive rate (TPR) while keeps false positive rate (FPR) below 14.3%. Moreover, as an exploration of the industrial Internet, we have deployed TagLeak in a real-world digital twin system Pavatar for liquid leakage detection in an ultra-high-voltage converter station (UHVCS).

The existing control tower at King County International Airport in Seattle, Washington, was severely damaged during the Nisqually Earthquake, February 28, 2001. As a result of the damage, the control tower was immediately closed and the existing timetable for a seismic retrofit of the control tower was expedited. The existing tower and associated support structures were founded on timber piles of unknown lengths (probably extending to depths between 25 and 35 feet); subsurface explorations indicated liquefiable soils to a depth of approximately 35 feet. The foundation retrofit included compaction grouting to densify the loose, liquefiable sands beneath the existing structures and the installation of drilled shafts adjacent to the tower to support the new structural steel bracing which was added to increase the resistance of the tower to overturning during the design earthquake. With the air traffic control operations being performed in a temporary facility, the urgency of performing the retrofit led the Federal Aviation Administration to negotiate a contract directly with the general contractor. This paper addresses the method of contract delivery, compaction grouting methods and results for liquefaction mitigation, and the construction of drilled shafts adjacent to an existing structure.

Oregon has been using open-graded hot mix on its roadway system since the late 1970s. Because of the performance of these early jobs (and the continued good performance of these mixes), open-graded hot mix has been the preferred choice for a surface course on Oregon highways. The following are described with respect to the use of these mixes in Oregon: historical perspective; design, including mix and structural design; construction, including quality control/quality assurance considerations; and maintenance and rehabilitation practices with porous pavements. The continued success of the use of these materials from both a performance and a public acceptance standpoint indicates they will be the pavement of choice in Oregon for the foreseeable future.

Crash prediction models are useful tools for identifying locations that have a higher risk of crashes and for prioritizing projects. The focus of this study was on developing macroscopic or planning-level models for pedestrian safety. Although such efforts have been undertaken, they have generally focused on specific cities or counties with census tracts as the unit of the analysis. This study analyzed a larger study area (the state of Florida) at a finer spatial resolution (census block groups instead of tracts). Four models were developed to determine the crash frequency for each census block group. The models were for total crashes, severe and fatal crashes, fatal crashes, and nighttime crashes. The estimated models captured the effects of several socioeconomic, transportation, land use, and contextual variables. The results generally reaffirmed past findings about the relationship between crashes and socioeconomic, transportation, and land use characteristics. However, the models in this study capture...

To support a great number of dispersed users in a wider area with high-speed communication services, we investigate a highly efficient medium access control (MAC) scheme for the hierarchical ring networks. In these networks, traffic congestion may happen due to the mismatch of transmission speed between backbone and outer rings. To cope with the issue, we propose a refined MAC protocol based on the cyclic reservation-based access control method for different network resources, viz. network bandwidth and buffers. By this approach, our protocol can achieve fair access to the network resources and avoid traffic congestion at the same time. Also, the networks will have the properties of extremely high throughput, low delay, fair access, simple implementation, and so forth. To evaluate the network, several simulative experiments are performed and some optimistic results are revealed.

A comprehensive quality assessment of the ozone products from 18 limb-viewing satellite instruments is provided by means of a detailed intercomparison. The ozone climatologies in form of monthly zonal mean time series covering the upper troposphere to lower mesosphere are obtained from LIMS, SAGE I/II/III, UARS-MLS, HALOE, POAM II/III, SMR, OSIRIS, MIPAS, GOMOS, SCIAMACHY, ACE-FTS, ACE-MAESTRO, Aura-MLS, HIRDLS, and SMILES within 1978–2010. The intercomparisons focus on mean biases of annual zonal mean fields, interannual variability, and seasonal cycles. Additionally, the physical consistency of the data is tested through diagnostics of the quasi-biennial oscillation and Antarctic ozone hole. The comprehensive evaluations reveal that the uncertainty in our knowledge of the atmospheric ozone mean state is smallest in the tropical and midlatitude middle stratosphere with a 1σ multi-instrument spread of less than ±5%. While the overall agreement among the climatological data sets is very good for large parts of the stratosphere, individual discrepancies have been identified, including unrealistic month-to-month fluctuations, large biases in particular atmospheric regions, or inconsistencies in the seasonal cycle. Notable differences between the data sets exist in the tropical lower stratosphere (with a spread of ±30%) and at high latitudes (±15%). In particular, large relative differences are identified in the Antarctic during the time of the ozone hole, with a spread between the monthly zonal mean fields of ±50%. The evaluations provide guidance on what data sets are the most reliable for applications such as studies of ozone variability, model-measurement comparisons, detection of long-term trends, and data-merging activities.

The nuclear propelled submarine, as a cargo vessel for transport of Arctic crude oil, is discussed as an element of a subsea transport system. The submarine is presented as technically feasible and the paper concludes such a subsea system to be economically competitive with other transport modes for delivery of Northern Alaskan and Canadian Arctic crudes to North Atlantic and European markets.

Abstract The corrosion influence on hydraulic pipelines safety mounted on product and chemical tankers has been presented in this paper. The issue of axial forces in pipelines mounted along ship open decks, resulting from ship hull deformations in waves, is highlighted. Corrosion degradation phenomena of hydraulic pipelines on open deck is described. The analysis of degradation effect on thickness of carbon steel material of pipes is given and influence of the effect on stress level increase in hydraulic pipelines during exploitation at sea is focused. The discussion about fighting against corrosion in hydraulic pipelines on open decks is performed. All the problems analyzed in the paper are based on examples of events observed on product and chemical tankers built in Szczecinska Shipyard, Szczecin, Poland.

The ASME pressure vessel and piping codes and standards provide excellent references for code writers in international jurisdictions when developing their own national codes and for safety authorities when developing regulatory acts. The inclination to customize this effort may add unnecessary complexity that unintentionally obscures the underlying engineering principles. In developing the Canadian pipeline code, the authors use the notion of maximum operating pressure or MOP similar to the MOP found in the ASME codes for pipelines. While the ASME code definitions are explicit and articulate, the MOP defined in the Canadian code is less so and has led to inadvertent confusion by industry users. Misunderstanding of complementary terminology used in ancillary ASME standards has contributed to further complexities. The use of the term, maximum allowable operating pressure or, MAOP in the ASME pipeline codes has further reduced clarity when integrating this term into international codes and regulatory acts. This paper examines, in detail, some aspects of the Canadian pipeline code and illustrates via a representative case study some of the aforementioned difficulties that have arisen. These difficulties resulted in unnecessary derating of assets by imposing operational limits that were well below actual capacity. A clear explanation of the engineering principles underlying the provisions for codes which use a “design by rules” philosophy will help operators set appropriate limits for both static and dynamic loads that may not be apparent in the specific codes considered and will be expository for regulators and code users in general.

Field experiments were performed in the Guanghua Oil Field, China, in order to evaluate the effectiveness of regional cathodic protection covering both the oil gathering pipeline network and the well casings. This paper reviews the results of the investigation emphasizing the necessity of joint protection for pipelines and casings. Recommendations are given concerning the rational layout of anodic groundbeds, distribution of protection current and monitoring the state of casing protection. Technological and economic problems involved in regional cathodic protection are also discussed. 1 ref.

A prominent question in transportation planning is how cities should regulate emerging modes, such as shared bikes and e-scooters. This pertains to a range of attributes, including pricing, use of the public right of way, number of vehicles in a fleet, and vehicle speeds. However, less attention has been paid to the way private operators spatially constrain access to their fleets, such as via the use of virtual geographic boundaries (hereafter “geofences”), or how municipalities have regulated these features. San Francisco, given it is home to a number of these schemes, presents a compelling case for studying geofences, and how regulators have sought to influence them to further public policy goals, including spatial equity. This study analyzes each bike and e-scooter geofence in San Francisco longitudinally from 2017 to 2019 via manual digitization of all geofences. This reveals high levels of overlap in the city’s dense northeast quadrant, with limited to no coverage in western neighborhoods. Each operator’s geofence expanded over this period, filling in gaps in the northeast quadrant and expanding outward in each direction. Review of permit guidelines and applications submitted by operators indicate that San Francisco’s regulations for geofences have been limited and inconsistent, which may have contributed to the concentration of services in one section of the city, as well as disconnected geofence “islands.” Together, these observations demonstrate that if broad geofence coverage (i.e., spatial equity) is an explicit municipal goal, such an aim must prominently feature into the regulatory process. This is particularly important given that operators, if left with freedom over geofence design, are likely to emphasize only a city’s densest areas, especially if tight caps are set on the allowed number of vehicles. Finally, this case also exemplifies that geofences are not drawn in a vacuum but instead relate to other permit conditions as well as pressure from community organizations.

39th IABSE Symposium - Engineering the Future, VANCOUVER, CANADA, 21-/09/2017 - 23/09/2017; Because of the competing demands for scarce resources (funds, manpower, etc) national road owners are required to monitor the condition and performance of infrastructure elements through an effective inspection and assessment regime as part of an overall asset management strategy. COST Action TU1406 aims to bring together research and practicing communities in order to establish a European guideline in this issue. In this context, this paper proposes a framework to classify research-based performance indicators related to highway bridge life-cycle analyses according to a parameter readiness level (PRL). Such a method examines program concepts, technology requirements, and demonstrated capabilities to rate the level of maturity of different categories of indicators. This approach is illustrated with some examples.

Abstract Advanced driver assistance systems (ADAS) can enhance road safety by sending warning signals to drivers. Multimodal signals are gaining attention in ADAS warning design because they offer redundant information that facilitates human–system communication. However, no consensus has been reached on which multimodal design offers optimal benefit to road safety. Icons iconically map the real world and are associated with fast recognition and response time. Therefore, this study aims to investigate whether visual and auditory icons will benefit the effectiveness of audiovisual multimodal warnings. Thirty-two participants (16 females) experienced four types of unimodal warnings (high and low mapping visual warnings and high and low mapping auditory warnings) and four types of audiovisual warnings (high mapping visual + high mapping auditory warning, low mapping visual + low mapping auditory warning, high mapping visual + low mapping auditory warning, and low mapping visual + high mapping auditory warning) in simulated driving conditions. Visual warnings are presented in a head-up display. Results showed that multimodal warnings outperformed unimodal warnings (i.e., modality effect). We found mapping effect in audiovisual warnings, but only high mapping auditory constituents benefited warning effectiveness. Eye movement results revealed that the high mapping constituents might distract drivers from the road. This study adds evidence that multimodal warnings can offer extra benefits to drivers and high mapping auditory signals should be included in multimodal warning design to achieve better driving performance.

Na presente dissertação, abordou-se o novo ecossistema da mobilidade mundial, tendo como foco a Mobilidade Elétrica em Portugal. O objetivo central do autor foi apresentar as melhores Recomendações para um Plano Estratégico focado na transição energética nacional e na forma de como se deverá abordar e tornar esta mudança o mais fácil e eficiente possível, rumo a uma mobilidade ecológica, mas sobretudo a um mundo ambientalmente sustentável e seguro. A metodologia aplicada baseou-se numa revisão de literatura, mas também num desenvolvimento teórico sobre o ecossistema atual, inovações e tendências, indústria automóvel, mercado automóvel e rede infraestrutural necessária a esta transição. Em cada tópico, discutiu-se as variantes, razões, explicações, consequências e implicações futuras de cada uma das questões em apreço. Como complemento à pesquisa teórica, o autor realizou 15 entrevistas a colaboradores de grandes empresas do setor automóvel e energético, assim como a utilizadores de automóveis distintos. Como resultado final, deverão ser consideradas as principais recomendações relativas a questões e barreiras existentes a resolver atualmente rumo a uma mobilidade elétrica eficaz e sustentável em Portugal: (1) Falta de infraestrutura de carregamento pública e privada; (2) Insuficiência da rede nacional de fornecimento energético; (3) Insuficiência de incentivos/benefícios; (4) Falta de informação e formação generalizada; (5) Excesso de burocracia, normas e leis aplicáveis ao tema; (6) Lentidão de processos associados a Câmaras Municipais; (7) Falta de parcerias/alianças estratégicas; (8) Falta de investimento em Big Data, software, tecnologia/inovação; (9) Falta de cultura de inovação e de investimento; (10) Falta de visão estratégica. In this dissertation, the new worldwide mobility ecosystem was approached, focusing on the Electric Mobility in Portugal. The author's central objective was to present the best Recommendations for a Strategic Plan focused on the national energy transition and on how to approach and make this change as easy and efficient as possible, towards ecological mobility, but above all to an environmentally friendly world. The applied methodology was based on a literature review, but also on a theoretical development about the current ecosystem, innovations and trends, the automotive industry, the automotive market and the infrastructure network necessary for this transition. In each topic, the variants, reasons, explanations, consequences and future implications of each of the issues were discussed. As a complement to theoretical research, the author conducted 15 interviews with employees of large companies in the automotive and energy sectors, as well as with two different car users. As a final result, the main recommendations regarding existing issues and barriers to be resolved currently towards an effective and sustainable electric mobility in Portugal should be considered: (1) Lack of public and private charging infrastructure; (2) Insufficiency of the national energy network; (3) Insufficient incentives and benefits; (4) Lack of information and generalized training; (5) Excessive bureaucracy, rules and laws applicable to the topic; (6) Slow processes associated with City Councils; (7) Lack of strategic partnerships and alliances; (8) Lack of investment in Big Data, software, technology/innovation; (9) Lack of a culture of innovation and investment; (10) Lack of strategic vision.

Traction inverter has been the subject of many studies due to its essential role in the proper performance of the drive system. With the recent trend in increasing the input voltage in battery-powered electric vehicles, multilevel inverters have been proposed in the literature as a promising substitute for conventional two-level traction inverters. A critical aspect of utilizing multilevel structures is employing proper control and modulation techniques. The control system structure must be capable of handling a number of key issues, like capacitor voltage balancing and equal power loss sharing, which arise in multilevel topologies. This paper presents a review of the present-day traction drive systems in the industry, control and modulation techniques for multilevel structures in the inverters, as well as the principal challenges that need to be addressed in the control stage of the multilevel traction inverter. A comparison has been made between different methods based on the most important criteria and requirements of the traction drive system. Finally, future trends in this application are presented and some suggestions have been made for the next generation of traction drives.

City events are being organized more frequently, and with larger crowds, in urban areas. There is an increased need for novel methods and tools that can provide information on the sentiments of crowds as an input for crowd management. Previous work has explored sentiment analysis and a large number of methods have been proposed relating to various contexts. None of them, however, aimed at deriving the sentiments of crowds using social media in city events, and no existing event-based dataset is available for such studies. This paper investigates how social media can be used to estimate the sentiments of crowds in city events. First, some lexicon-based and machine learning-based methods were selected to perform sentiment analyses, then an event-based sentiment annotated dataset was constructed. The performance of the selected methods was trained and tested in an experiment using common and event-based datasets. Results show that the machine learning method LinearSVC achieves the lowest estimation error for sentiment analysis on social media in city events. The proposed event-based dataset is essential for training methods to reduce estimation error in such contexts.