Nemzetközi szemle: Október
Aszfaltbeton laboratóriumi és helyszíni minták volumetrikus és mechanikai tulajdonságainak összehasonlítása
Comparing the Volumetric and Mechanical Properties of Laboratory and Field Specimens of Asphalt Concrete
L. N. Mohammad, M. A. Elseifi, S. B. Cooper, C. S. Hughes, J. W. Button, E. L. Dukatz, Jr
Louisiana State University USA
Terjedelem: 89 oldal
Mix properties that deviate appreciably from design during the production and construction of asphalt mixtures often lead to premature pavement distress or even failure. The objective of this project was to quantify sources and causes of variability in the measurements of volumetric and mechanical properties of dense-graded asphalt mixtures for three types of specimens that may be encountered during design, production, and construction. In addition, the effects of variation among specimen types on pavement performance prediction were evaluated. This was accomplished by evaluating common volumetric and mechanical properties of the three specimen types (design, production, and construction) from a nationwide compilation of 11 mixtures from various states throughout the
United States. Variations in key production process factors—specifically the return of baghouse fines, delay in specimen fabrication, aggregate absorption, aggregate hardness, and stockpile moisture content—were evaluated in this study. For each mixture, the following volumetric and mechanical properties were evaluated for the three specimen types: Volumetric properties: air voids, voids in the mineral aggregate, voids filled with asphalt, aggregate bulk specific gravity, mixture maximum specific gravity, asphalt binder content, and gradation. Mechanical properties: loaded-wheel test (LWT) rut depth, axial dynamic modulus, and indirect tensile test (IDT) dynamic modulus.
Burkolatállapot és fenntartási hatékonyság értékelése szenzor adatok összevonásával
A Sensor Fusion Approach to Assess Pavement Condition and Maintenance Effectiveness
Szerző(k): R. Bridgelall, Y. Huang, Z. Zhang, D. D. Tolliver
North Dakota State University USA
Terjedelem: 39 oldal
Transportation agencies use a variety of methods to evaluate the condition of pavements and the characteristics of their use. Methods range from in-pavement sensors to ride quality characterizations that require specially instrumented probe vehicles. However, the extensive labor, specialized training, and high cost associated with the large variety of existing approaches limit their ability to scale in frequency and coverage. Infrequent monitoring diminishes the accuracy of assessing infrastructure needs and of evaluating maintenance effectiveness. This research developed a sensing approach that extends the capability of in-pavement sensors beyond their ability to measure just loading and condition parameters. Specifically, the approach links the output of durable in-pavement strain sensors to common roughness indices. However, to maintain their accuracy throughout the life cycle of the pavement, models that use their output must be calibrated periodically. Therefore, this research also developed a localized roughness measurement method based on connected vehicle sensing to calibrate the models. Field experiments validated that the relative roughness indices of the two methods agreed within 3.3%. This result demonstrates that it is possible to build smart roads with embedded strain sensors that can also report roughness levels continuously, without requiring special probe vehicles.
Integrált dinamikus közösségi közlekedési megoldások prototípus fejlesztése és bemutatása
Prototype Development and Demonstration for Integrated Dynamic Transit Operations
Szerző(k): T. Timcho, G. Zink, B. Kellom, R. Lordo, L. Hartman, K. McKee, S. Mishra, C. Schweiger, M. McCord, R. Mishilani
Battelle Memorial Institute USA
Terjedelem: 136 oldal
This document serves as the Final Report specific to the Integrated Dynamic Transit Operations (IDTO) Prototype Development and Deployment Project, hereafter referred to as IDTO Prototype Deployment or IDTO PD project. This project was performed under contract to the U.S. Department of Transportation (U.S. DOT) Intelligent Transportation Systems (ITS) Joint Program Office (JPO) in cooperation with the Federal Transit Administration (FTA). This final report provides a summary of the activities performed in conducting the IDTO PD project and documents the findings, lessons learned, and future considerations generated as an outcome of this work. As a prototype, IDTO was successful. It proved to be beneficial to the traveler, as throughout the demonstration period, users returned to use the application for trip planning/informational searches, and of those, over 25% took the action to monitor the trip and enable monitoring of transfers by the agencies to hold to allow for successful transfers. IDTO proved to be robust, with an uptime well over 95% based on 161 of 164 operational days. IDTO proved to be transferrable, deployed both in Columbus and Central Florida using the same core software tools. IDTO proved to be beneficial to transportation agencies, providing greater insight into system performance and allowing for adjustment to improve service. And finally, IDTO was insightful, identifying lessons learned that shape future research and deployment considerations.
A kerékpáros infrastruktúra gazdasági és társadalmi hatásainak értékelése
Evaluating the economic and social impacts of cycling infrastructure
Szerző(k): K. Farla, P. Simmonds, C. Rosemberg, M. Rentel
Technopolis group UK
Terjedelem: 94 oldal
This report presents the results of a study to research the options for robustly evaluating the economic and social impacts of investments in new or improved cycling infrastructure, in a mixture of different types of urban and rural areas. The report has been written for evaluation practitioners and commissioners, and while it attempts to avoid using evaluation jargon without suitable explanations, the document is rather more discursive than would be appropriate for a more general reader.
Állami közutak megvilágítási tanulmánya
Study on Illumination for State Highways
Szerző(k): Y. Wang, Y. Zou
University of Washington USA
Terjedelem: 100 oldal
Increasing budget pressures are causing the Washington State Department of Transportation (WSDOT) to look for ways to reduce costs. WSDOT currently owns and operates illumination fixtures on state freeways and highways with annual operating costs measured in millions of dollars. Given the pressures to reduce the WSDOT budget, it is important to have a complete understanding of the means available to reduce operating and capital costs with the least negative impact on service, safety and sustainability. There are several ways that the WSDOT can reduce expenditures on illumination. One way is to use more efficient lighting technologies. A second is to operate illumination more judiciously. Another option is to install fewer luminaires, remove superfluous luminaires and consolidate luminaires. Executing these options effectively requires the WSDOT to collect additional information regarding current and near future illumination practices and technologies. A natural way in the process of revising and adapting WSDOT’s illumination standards is examining how the WSDOT standards compare to other state DOTs, utilities, cities, counties and other public entities internationally. Given the work required to revise, publish and promulgate a new illumination standard, it is advisable to examine the current state of practice in illumination standards in order to inform comprehensive updates. Toward that end, a comprehensive review of illumination design standards, LED illumination technologies and illumination control systems is useful for revising illumination standards. To address these aspects of illumination operation and design, a thorough literature review of existing illumination products, illumination control systems, and illumination spectrum technologies is conducted. This report reviewed existing public agency illumination standards domestically and internationally and outlined the difference in designing standards. An overview of existing luminaire technology performance, as well as operational and maintenance characteristics are provided. In addition, available illumination control and spectrum technologies for performance characteristics are summarized. The results of this literature review are useful for design and business case decisions regarding illumination installation, maintenance, and operation.
A közlekedési hálózat hatékonyságának javítása a közösségi közlekedést támogató közúti stratégiák bevezetésével
Improving Transportation Network Efficiency Through Implementation of Transit-Supportive
Szerző(k): P. Ryus, K. Laustsen, K. Lee, S. Beaird, E. Lindstrom, J. Crisafi, Z. Bugg, A. Skabardonis, S. Langdon
Kittleson & Associates, Inc., Savant Group, Inc. USA
Terjedelem: 195 oldal
This report documents the research conducted by TCRP Project A-39, Improving Transportation Network Efficiency Through Implementation of Transit-Supportive Roadway Strategies. This project conducted an extensive review of transit preferential treatments used in the U.S. and internationally, including information on when these treatments are applied and how they are designed. The project interviewed a number of transit and roadway agencies to identify lessons-learned and best practices from actual project implementations, with a particular focus on successful techniques for transit agencies, roadway agencies, and project stakeholders to work together toward outcomes that benefit all parties involved. This report also presents findings from a series of gap-filling research efforts on innovative international strategies not yet in common use in the United States; a simulation study of the effects of stop location, transit signal priority, and queue jumps on bus and general traffic travel times and travel time variability; an evaluation of selected strategies implemented in the Seattle area; and identifying conditions when the delay benefit produced by a strategy at an upstream intersection is lost at the next downstream signal, resulting in no net benefit. Finally, this report presents recommendations for changes to the next edition of AASHTO’s Guide for Geometric Design of Transit Facilities on Highways and Streets, based on the findings of this project.
A közösségi közlekedést támogató közúti stratégiák kézikönyve
A Guidebook on Transit-Supportive Roadway Strategies
Szerző(k): P. Ryus, K. Laustsen, K. Blume, S. Beaird, S. Langdon
Kittleson & Associates, Inc., Savant Group, Inc. USA
Terjedelem: 211 oldal
TCRP Report 183: A Guidebook on Transit-Supportive Roadway Strategies is a resource for transit and roadway agency staff seeking to improve bus speed and reliability on surface streets while also addressing nearby land uses and the needs of motorists, bicyclists, and pedestrians. The guidebook:
discusses why improving bus speed and reliability is important for transit, roadway and planning agencies, as well as the community at large; provides guidance on planning and implementing a successful project, with particular attention to the coordination and communication needs of project stakeholders; defines and describes 34 strategies for improving bus speed and reliability, including a range of transit operation, traffic control, infrastructure, and bus lane strategies; provides guidance on selecting an appropriate strategy to address a particular cause of a bus speed or reliability problem; and gives case study examples of how transit and roadway agencies have successfully worked together to implement these strategies.
Az EU közlekedése számokban – statisztikai zsebkönyv 2015
EU transport in figures – Statistical pocketbook 2015
Szerző(k): EU Publications Office
Terjedelem: 77 oldal
Transport represents a crucial sector of the economy. This publication provides an overview of the most recent and most pertinent annual transport-related statistics in Europe. It covers the European Union and its 28 Member States and, as far as possible, the current EU candidate countries and the EFTA countries. The content of this pocketbook is based on a range of sources including Eurostat, international organisations, national statistics and, where no data were available, own estimates. Own estimates have mainly been produced to get an idea of the EU total. At the level of individual countries, they are merely indicative and should by no means be (mis-)interpreted as ‘official’ data.
The publication consists of three parts: a general part with general economic and other relevant data, a transport part covering both passenger and freight transport as well as other transport-related data, and, finally, an energy and environmental part with data on the impact which the transport sector has on the environment. The tables of this pocketbook may also be found on the Europa site at:
Javított tömörítés a tartósság növelésére és a burkolat élettartam kiterjesztésére: irodalmi áttekintés
Enhanced Compaction to Improve Durability and Extend Pavement Service Life: A
Szerző(k): Nam Tran, Ph.D., P.E., LEED GA; Pamela Turner; James Shambley
Auburn University USA
Terjedelem: 25 oldal
This literature review was conducted to provide information to support the FHWA Asphalt Pavement Technology Program strategic direction on extending pavement service life through enhanced field compaction. The results from the past studies clearly indicate the effect of low in-place air voids on the fatigue and rutting performance of asphalt pavements. A 1% decrease in air voids was estimated to improve the fatigue performance of asphalt pavements between 8.2 and 43.8% and the rutting resistance by 7.3 to 66.3%. In addition, a 1% reduction in in-place air voids can extend the service life by conservatively 10%. Based on these results, a life cycle cost analysis (LCCA) was conducted on two alternatives in which the exact same asphalt overlay would be constructed to 93% and 92% densities to illustrate the effect of in-place air voids on the life cycle cost of asphalt pavements. The LCCA results show that the user agency would see a net-present-value cost savings of $88,000 on a $1,000,000 paving project (or 8.8%) by increasing the minimum required density by 1%. Due to its significant effect, the cost of providing increased in-place density can be significantly less than the operation, maintenance, and road user cost savings realized due to extended service life of the pavements. In an AASHTO survey of state agencies’ targets for field compaction conducted in 2007, the majority of states responding to the survey had a compaction target of 92 percent, but over one-third of the responding agencies had compaction targets less than 92 percent. Most of these in-place density requirements currently adopted by states were determined based on what levels of in-place density could be achieved in the past using prior construction technologies. Since in-place density has a significant impact on the performance of asphalt pavements, agencies may consider implementing a higher in-place density requirement that can be achievable by following best practices and adopting new asphalt pavement technologies and knowledge gained from recent research. Some of these technologies and knowledge, including warm mix asphalt, intelligent compaction, improved construction joints, and improved agency specifications to incentivize achieving higher in-place densities, are briefly discussed in this report.
A visszanyert aszfalt használatának maximálása az aszfaltkeverék tervezésben: helyszíni értékelés
Maximising the Use of Reclaimed Asphalt Pavement in Asphalt Mix Design: Field Validation
Szerző(k): Dr Laszlo Petho, E. Denneman
a letöltéshez ingyenes regisztráció szükséges
Terjedelem: 77 oldal
The use of recycled asphalt pavement (RAP) in asphalt mixes provides a vital basis for sustainable development. Maximising the re-use of RAP in its highest value application, as new asphalt product, has significant economic and environmental benefits.
The overall goal of the study was to provide guidance on the design and specification of RAP mixes and to reduce uncertainty surrounding the performance of asphalt mixes designed and manufactured with RAP. It was found that the binder blend characterisation according to AGPT/T193 is valid for a wide range of asphalt mixes and therefore it can be used with confidence for designing the binder blend in mixes containing RAP. It was also found that the addition of RAP to asphalt mixes, with different percentages of RAP and manufactured in different types of asphalt plants, does not have an adverse impact on the performance. This was assessed by using performance-based tests such as flexural stiffness, wheel-tracking and moisture sensitivity. Test results showed that the addition of 40% RAP, validated on large-scale asphalt production, did not have a negative effect on the in situ workability and thermal segregation.
A feasibility study concluded that the RAP can be subjected to recycling multiple times. A long-term monitoring of RAP sources showed that there is little variation within a stockpile; however, there is significant variation within stockpiles over time. A comprehensive sensitivity study, using the Monte Carlo simulation, was performed as part of the validation process to provide insight into the variability, impact and risk assessment for asphalt mixes containing RAP. Binder blend characterisation should be required for asphalt mixes with RAP content greater than 15%.