Nemzetközi szemle: November

Teljesítmény alapú előírások fejlesztése a Louisiana államban használt aszfaltkeverékekhez

Development of Performance-based Specifications for Louisiana Asphalt Mixtures

Szerző(k):
L. N. Mohammad, M. Kim, H. Challa
Louisiana State University USA
Terjedelem: 149 oldal

Quality control and quality assurance (QC/QA) specifications typically define the asphalt mixtures by how close the as-built mixture meets the requirements of the as-designed mix. A common QC/QA specification for asphalt pavement construction is based on controlling the volumetric properties of compacted asphalt mixtures such as air voids, asphalt content, and aggregate gradation. However, there is no fundamental correlation to ensure that these volumetric properties are sufficient to provide satisfactory long term performance of the asphalt pavements. In order to address the issue in the current QC/QA specification, it is needed to develop a performance-based specification (PBS), which measures the mechanical and/or engineering properties of asphalt mixture as performance predictors of finished pavements. Such a PBS must be verified to actual field performance data. The objective of this study is to develop a framework for the implementation of PBS for Louisiana. To achieve this objective, nine asphalt paving projects were selected across the state. A total of 14 pavement sections that includes 21 asphalt mixtures were selected. A suite of laboratory tests using the Hamburg type loadedwheel tester (LWT) and the semi-circular bending (SCB) device were performed to evaluate the rutting (in terms of rut depth, RD) and cracking resistance (in terms of critical strain energy release rate, Jc), respectively. In addition, indirect tensile dynamic modulus test (IDT |E*|) were conducted to evaluate the viscoelastic properties of the asphalt mixtures. The dynamic modulus from IDT |E*| can be used as a material input in the Mechanistic-Empirical Pavement Design Guide (MEPDG) software to predict the 20-year projected distresses. The field distress data were obtained from Louisiana pavement management system (LA-PMS) for the selected projects and used to calibrate the 20-year projected rutting by the MEPDG simulations. From the comparison analyses, it was observed that the LWT measured rut depths of 6 mm or less and 10 mm or less can be the tentative quality limits for the Level 2 and Level 1 Louisiana asphalt pavements, respectively. Similarly, the minimum SCB Jc values of 0.6 and 0.5 kJ/m2 for Level 2 and Level 1 asphalt pavements, respectively, seemed to serve well as the tentative criteria to avoid crack related problems. Along with the tentative rutting and cracking performance criteria, a draft sampling and testing plan of the PBS was proposed. A continued effort to collect more field and laboratory performance data in accordance with the proposed PBS is desired to validate the tentative performance criteria and to address unknown challenges for DOTD and contractors in implementing the proposed PBS.

A főpálya folyamatos megvilágításának biztonsági teljesítmény értékelése Washington állam autópálya szakaszain

Evaluation of the Safety Performance of Continuous Mainline Roadway Lighting on Freeway Segments in Washington State
Szerző(k):
I. van Schalkwyk, N. Venkataraman, V. Shankar, J. C. Milton, T. J. Bailey, K. Calais
Washington State Department of Transportation USA
Terjedelem: 84 oldal

Washington State Department of Transportation (WSDOT) evaluated continuous roadway lighting on mainline freeway segments in Washington State. An extensive literature review on the safety performance of roadway lighting was completed. As part of this research effort WSDOT developed multivariate random parameter (RP) models with specific lighting variables for continuous lighting on mainline freeway segments. Roadway lighting is often used as a countermeasure to address nighttime crashes and this research evaluates common assumption related to roadway lighting. The models developed for this research use crashes from the end of civil dusk twilight to the start of civil dawn twilight since lighting systems are of limited value outside these timeframes. Natural light conditions were estimated for crashes based on location and time of the crash event. Based on the RP results, the research team concludes that the contribution of continuous illumination to nighttime crash reduction is negligible. In addition to the findings on safety performance, a pilot LED project on US101 demonstrated that LED roadway lighting can significantly increase energy efficiency and environmental stewardship (e.g., reducing greenhouse gas emissions) while maintaining safety performance outcomes. The research team recommended modification to WSDOT design policy, including removal of the requirement of continuous mainline lighting and reduction of lighting where segment specific analysis indicates appropriate.

Együttműködő jármű-infrastruktúra rendszerek bevezetése a sebesség harmonizálás javítására

Introduction of Cooperative Vehicle-to-Infrastructure Systems to Improve Speed Harmonization
Szerző(k):
David Hale, Thomas Phillips, Kelli Raboy, Jiaqi Ma, Patrick Su, Xiao-Yun Lu, Hesham Rakha, and Daniel J. Dailey
Leidos, Inc. USA

Terjedelem: 54 oldal

This project executed a preliminary experiment of vehicle-to-infrastructure (V2I)-based speed harmonization in which speed guidance was communicated directly to vehicles. This experiment involved a set of microsimulation experiments and a limited number of prototype field runs. The simulation experiments produced mixed results in terms of system-wide benefits. The field runs demonstrated that connected and automated vehicles can successfully implement V2I-based speed harmonization and significantly reduce speed oscillations in their vicinity but do not have a significant impact on aggregate average speeds or travel times.

Automatizált és összekapcsolt járművek – a 9. Egyetemi Közlekedési Központok fókusz konferencia összefoglalása

Automated and Connected Vehicles – Summary of the 9th University Transportation Centers Spotlight Conference
Szerző(k):
K. F. Turnbull szerkesztő
Transportation Research Board USA

Terjedelem: 90 oldal

Connected vehicle (CV) and automated vehicle (AV) technologies are being developed, tested, and deployed by a variety of private companies and public agencies. CVs and AVs may improve safety, reduce emissions, and improve the efficiency and reliability of the transportation system. The Transportation Research Board (TRB) hosted a conference entitled Automated and Connected Vehicles in Washington, D.C., in November 2015. Speakers highlighted research, testing, and deployment activities under way at the national, state, and local levels. Other speakers provided perspectives from the insurance industry, self-driving technology and mapping companies, and carsharing businesses.

Kerékpár megosztó állomások elhelyezési útmutatója

Bike Share Station Siting Guide
Szerző(k):
National Association of City Transportation Officials USA
Terjedelem: 74 oldal

The NACTO Bike Share Station Siting Guide provides high-level guidance on physical bike share station siting types and principles. Selecting good individual station locations while maintaining walkable distances between stations throughout the system can maximize ridership and increase safety.
The NACTO Bike Share Siting Guide is part of a collection of resources created in collaboration with the Better Bike Share Partnership (www.betterbikeshare.org).

MPD (átlagos profilmélység) és IRI (nemzetközi egyenetlenségi index) a nagy méretű tehergépjárművek nyomvonalában – hálózati mérések

MPD and IRI in the position of large goods vehicles – Network measurements
Szerző(k):
O. Eriksson, Th. Lundberg
Swedish National Road and Transport Research Institute (VTI) Sweden
Terjedelem: 32 oldal

Road monitoring of the state road network in Sweden includes the longitudinal measurements of International Roughness Index (IRI) and Mean Profile Depth (MPD). The paths of the longitudinal measurements correspond with the surface contact points of the wheels of a light passenger vehicle.
This data can be used to estimate values for different properties such as, rolling resistance, comfort and vehicle wear. Knowledge of the surface condition (IRI and MPD values) at the surface contact points associated with a large goods vehicle would prove to be useful when estimating similar values on an entire or local road network, including all vehicle types. If these conditions are not known, it is important to know how they differ from the measured path. In Sweden, lateral position comparisons made between medium and large goods vehicles show that right wheel track positions are not similar. This applies to larger and wider roads (typical motorways and other wide main roads). Using this knowledge, VTI’s measurement vehicle was equipped with two extra texture lasers which were mounted to the right of the ordinary texture laser in the right wheel track. Data was collected on a road network with mixed categories of road standard varying from secondary roads to motorways. The study of differences in IRI and MPD values, corresponding to the position of light passenger vehicles right wheel path and two other paths, 25 centimetre and 45 centimetre further out to the right (position of medium and large goods vehicles), showed rather small values in average differences. The differences are presented for different pavement types. An attempt to predict differences between the tracks for each 20-meter section failed. Inconsistent results meant that it was not possible to explain the differences. A statistical analysis procedure was used to calculate the global differences for the mean difference and error margin. The statistical analysis procedure is also presented in the report. The result for MPD showed very small global differences in the different lateral positions and normally the error margin is bigger than the average difference. Results regarding IRI values were more consistent. IRI values were greater closer to the road shoulder and the error margins were usually smaller than the differences.

Gyalogos és kerékpáros teljesítmény mutatók kialakításának útmutatója

Guidebook for Developing Pedestrian and Bicycle Performance Measures
Szerző(k):
C. Semler, A. Vest, K. Kingsley, S. Mah, W. Kittelson, C. Sundstrom, K. Brookshire
UNC Highway Safety Research Center, Kittelson & Associates, Inc. USA

Terjedelem: 100 oldal

This guidebook is intended to help communities develop performance measures that can fully integrate pedestrian and bicycle planning in ongoing performance management activities. It highlights a broad range of ways that walking and bicycling investments, activity, and impacts can be measured and documents how these measures relate to goals identified in a community’s planning process. It discusses how the measures can be tracked and what data are required, while also identifying examples of communities that are currently using the respective measures in their planning process. This report highlights resources for developing measures to facilitate high quality performance based planning.

Az építési információs modellezés (BIM) bevezetése a közbeszerzésben

The implementation of BIM within the public procurement
Szerző(k):
M. Bolpagni
VTT Technical Research Centre of Finland
Terjedelem: 242 oldal

Recently more and more Public Sectors have been paying close attention to save cost and, at the same time, improve efficiency. Usually, the Construction Industry has a relevant annual turnover, which represents an important part of the GDP for most of the EU countries and concerns in a large part the Public Sector. Thus, some Public Clients, such as UK, are adopting new strategies in order to improve the current situation. One of these strategies is Building Information Modelling (BIM), which forces all the parties involved in the process to adopt a collaborative approach reducing inefficiencies. Moreover, also the European Parliament is going to encourage the BIM adoption to ‘modernise the procurement process and ensure greater efficiencies’. The EU Directive will be an important push to reform the EU Members’ Public Construction Procurement.

Az építési információs modellezés (BIM) bevezetése a közbeszerzésben

The implementation of BIM within the public procurement

Szerző(k):
M. Bolpagni
VTT Technical Research Centre of Finland
Terjedelem: 242 oldal

Recently more and more Public Sectors have been paying close attention to save cost and, at the same time, improve efficiency. Usually, the Construction Industry has a relevant annual turnover, which represents an important part of the GDP for most of the EU countries and concerns in a large part the Public Sector. Thus, some Public Clients, such as UK, are adopting new strategies in order to improve the current situation. One of these strategies is Building Information Modelling (BIM), which forces all the parties involved in the process to adopt a collaborative approach reducing inefficiencies. Moreover, also the European Parliament is going to encourage the BIM adoption to ‘modernise the procurement process and ensure greater efficiencies’. The EU Directive will be an important push to reform the EU Members’ Public Construction Procurement.

Építési információs modellezés repülőterek számára

Building Information Modeling for Airports
Szerző(k):
T. L. McCuen, D. M. Pittenger
University of Oklahoma, Arbor Services, USA

Terjedelem: 101 oldal

Building information modeling (BIM) is a digital representation of a facility’s physical and functional characteristics. It can be shared by planners, designers, constructors, operators, and maintainers to provide reliable information for decision making throughout the facility’s life cycle. BIM offers tools that allow airport decision makers to understand all components of a facility, their location, and their attributes, both graphically and systematically, to minimize the total cost of owning and operating an airport facility. The objective of this synthesis is to deliver information about the general, current state of the art and practice in BIM applications in industry and to provide a snapshot of existing experience related to the emergence of BIM in North American airports. The goal is to provide information about BIM and assist airports in understanding available opportunities, benefits, and value related to engaging in BIM. Currently, little guidance is available for airport operators on how to implement BIM from project conception through planning, design, construction, commissioning, operation, maintenance, and demolition. Although several airports have utilized some BIM tools and processes in their development programs, there is a shortage of documentation on benefit metrics and lessons learned. The synthesis study methodology included a comprehensive literature search and survey (i.e., questionnaire and case example interviews), designed to capture current airport BIM practices and experiences. Purposive sampling was used to target a group of airports in North America, as well as other airport architecture, engineering, and construction (AEC) professionals, with known BIM use or use of BIM-related technologies. Fourteen of the solicited 19 airports provided survey responses. Adding in AECs, a total of 18 organizations participated in the survey. Although only potential BIM adopters were targeted, all levels of BIM engagement are demonstrated in the results, from no engagement to full engagement, as presented in this report.

Életciklus költség elemzés a közúti vagyongazdálkodásban

Life-Cycle Cost Analysis for Management of Highway Assets

Szerző(k):
Applied Engineering Management Corporation, Venner Consulting, USA

Terjedelem: 47 oldal

MAP-21 (the Moving Ahead for Progress in the 21st Century Act) requires agencies to incorporate life-cycle cost analysis (LCCA) and risk-based analyses into their asset management plans for, at a minimum, pavements and bridges on the National Highway System (NHS) and encourages similar proactive management of other transportation assets. To assist highway agencies in this task, this study was developed to provide insight as to the state of the practice of LCCA and the activities of state highway agencies. The objective of this project was to develop an inventory of quantitative asset-level, project-level, or corridor-level processes or models for predicting life-cycle costs associated with the preservation and replacement of highway assets, through a literature review, nationwide survey of highway agencies, and case studies that documented specific highway agency experiences with LCCA.