Nemzetközi szemle: Október
Az aszfalt kötőanyag reológiai paramétereinek múltja, jelene és jövője
Past, Present, and Future of Asphalt Binder Rheological Parameters
Szerző(k): Christensen, D. Mensching, G. Rowe, R.M. Anderson, A. Hanz, G. Reinke, D. Anderson
Transportation Research Board USA
Terjedelem: 88 oldal
The notion of an aging and under-funded infrastructure in the United States is widelyaccepted. Current legislation calls for performance targets to be established to aid not only in the administering of funds, but also to assist states in identifying high-risk practices and roadways within their own networks. In addition to the performance targets, agency officials are looking to design and construct longer-lasting pavements through performance specifications.In the late-1980s and early-1990s, the Strategic Highway Research Program developed a performance-based purchase specification for asphalt binders. High, intermediate, and low temperature performance is considered at single time or frequency points evaluated at different temperatures to meet American Association of State and Highway Transportation Officials (AASHTO) thresholds. Over the last 20 years, members of the asphalt pavement industry haven expressed concerns over the ability of the performance-grading thresholds to accurately assess field performance. That concern has been magnified in recent years due to the increasing representation of polymers, recycled materials, and other products in asphalt pavements.As industry experts explore refinements to the performance-grading system, rheological analysis of asphalt binders is coming to the forefront. This analysis may include inter conversions between other viscoelastic properties (i.e., creep compliance to relaxation modulus) or mastercurve determination. This more comprehensive look at material behavior is likely needed because modifiers and other additives may render some of the more basic rheological assumptions invalid. While this is not necessarily indicative of poor performance, the behavior across the expected temperature and frequency conditions is beneficial nonetheless.
A közlekedéstervezés és a beruházások javítása az elérhetőségi mutatók használatával
Improving Transport Planning and Investment Through the Use of Accessibility Indicators
Szerző(k): International Transport Forum, OECD
Terjedelem: 42 oldal
Generating adequate access to opportunities is a fundamental condition for ensuring well-being. Yet, many transport policies are still more focused on generating physical movement and increasing speeds than in guaranteeing access. This has often resulted in induced demand (i.e. the phenomenon that increasing road capacity leads to an increase in traffic volumes), exacerbating congestion, pollution and greenhouse gas emissions. A focus on private motorised transport also tends to exacerbate inequality and social exclusion. By shifting the focus of policies and investment from accommodating traffic growth to improving accessibility authorities could deliver simultaneously on a wide set of sustainability goals. The development of accessibility indicators and their inclusion in policy and decision-making frameworks is key to moving in this direction. These tools can help increase authorities’ capacity to track effectiveness of transport and urban development policies in terms of the accessibility delivered and to prioritise investment in a way that is coherent with enhancing access to opportunities, especially for vulnerable groups. In sum, these tools are key to effective accessibility-based policy, planning and investment frameworks in which accessibility considerations systematically guide decisions. The ITF is working with the European Commission to develop accessibility indicators for benchmarking cities in terms of the way they deliver access across the functional urban area. As part of this effort a workshop was convened in 2018 on “Improving Transport Planning and Investment through the Use of Accessibility Indices” for stakeholders and experts to share their experience in developing operational accessibility indicators. The results are summarised in this report.
Burkolatlan utak állapotának értékelési folyamata
Assessment process for the condition of unsealed roads
Szerző(k): Henning, A. McCaw, N. Bennett
University of Auckland, New-Zealand
Terjedelem: 58 oldal
Unsealed roads remain the backbone of the New Zealand’s economy. Less than 40% of local roads in New Zealand are unsealed, yet most of New Zealand’s farm produce, important tourism and forestry harvest start their journey to the international market on unsealed roads. It is therefore essential to plan the investment into this network based on appropriate data. Traditional data collection using visual assessments was not sustainable given the fast-changing nature of unsealed roads. This has left councils not knowing what data to collect on the network, thus necessitating this research project that aimed at developing data collection processes to facilitate better decision making and performance reporting. This report recommends frameworks for decision making at strategic and tactical asset management levels alongside a performance framework consistent with the One Network Road Classification process. These frameworks were the primary input into the process for condition data collection and broader data requirements for unsealed roads.
Az átlagos napi forgalom állami szintű becslésének költséghatékony stratégiája
Cost Effective Strategies for Estimating Statewide AADT
Szerző(k): Chowdhury, N. Huynh, S.M.Khan, Z.Khan,K. Brunk, M.Torkjazi, S.Islam, McK.Keehan,S. Shiri
Clemson University, USA
Terjedelem: 148 oldal
Annual Average Daily Traffic (AADT) is defined as the average daily measure of the total volume of vehicles ona roadway segment over a year. AADT is one of the most important traffic measures used in any transportation engineering project (e.g., highway investment decision making, transportation planning, highway maintenance,air quality compliance study, traffic safety analysis, and travel demand modeling). Thus, the accuracy of AADT estimation is critical for any transportation problems that use AADT as an input parameter. This report covers the various aspects of AADT data collection and estimation. The researchers reviewed existing legislation for AADT data collection, including Highway Performance Monitoring System and Highway Safety ImprovementProgram. A survey, regarding current data collection procedures and needs, was distributed to both U.S. Statesand Canadian Provinces as well as a second version for South Carolina cities and counties. A review was also conducted on each available technology for data collection from simple but effective pneumatic tubes to hightech video systems. From this information, the research team developed recommendations for data collection improvements in South Carolina. Lastly, this project developed and evaluated three AADT estimation models and determined that a Machine Learning model, Support Vector Regression, had the most cost-effective andaccurate AADT prediction. Based on this finding, the research team developed a computer software, called estimAADTion, which can be used by the SCDOT to predict AADT based on 24-hour short-term counts.
Az önvezető járművek figyelembe vételének módjai Virginia állam hosszú távú utazási igény modellezésében
Ways to Consider Driverless Vehicles in Virginia Long-Range Travel Demand Models
Szerző(k): S. Miller, D. Kang
Virginia Transportation Research Council USA
Terjedelem: 121 oldal
Regional travel demand models are an institutionalized element of the transportation planning process and require multiple years to develop, calibrate, and deploy. Because transportation planners are being asked immediately how a new technology, i.e., driverless vehicles (DVs), may affect travel demand, this study, using a case study approach with one particular region, identified how such models can be modified to incorporate the potential impacts of DVs and to answer related questions of interest to stakeholders. The DVs described in this report are presumed to be completely autonomous and are what SAE International refers to as Level 5 vehicles. A key finding is that it is possible to address some impacts of DVs in the model, such as changes in capacity, mode share, travel by age groups that traditionally have had less access to vehicles, trip length, and sharing of such DVs. Execution of the regional model using these modifications provided answers to some questions of interest; for example, a decrease in capacity during the transition period to DVs could lead to a substantial increase in delay (a 46% increase in vehicle hours traveled [VHT] in the case study area, whereas greater access to DVs by groups that traditionally have not had access to a vehicle suggests only a modest increase in delay (a 3.3% increase in VHT). Incorporation of such impacts into the model can also inform policies; for example, it is possible that the advent of DVs could encourage commuters to seek to avoid parking fees by either sending privately owned vehicles back home or sharing subscription-based DVs. Both situations increased zero occupant vehicle trips in the case study model, but the former increased nitrogen oxide emissions by an estimated 11.64% whereas the latter increased them by 2.08% to 6.65% depending on the manner in which the sharing occurred.
A területhasználat fejlesztési potenciálja és az elektromos kerékpározás elemzése
Land Use Development Potential and E-bike Analysis
Szerző(k): T.P.Uteng, A. Uteng, O.J. Kittilsen
TOI, Ramboll Norge AS, Norway
Terjedelem: 64 oldal
Increasing cycling shares is a part of the urban and transport planning mandate for the Norwegian urban regions. The pathways to increase bicycling shares can be plotted at both macro and micro levels. At micro levels, road designs and measures to both improve the conditions for cyclists and make cycling paths safer can lead to potential increase in bicycling. At the macro level, land use planning can assist in increasing bicycling usage. In this report, we analyse the issue at a macro level for the four largest cities in Norway – Oslo, Bergen, Trondheim and Stavanger. Analysis is based on INMAP model, which has previously been employed to estimate the mutual effects of land use plans, infrastructure provision and transportation in Norway. This study strongly recommends integrating the impact of E-bikes with land-use planning processes and decisions. Through active land-use management, the municipalities and regional development authorities can steer urban mobility to a more sustainable direction.
A 12. Nemzeti Közlekedési Vagyongazdálkodási Konferencia előadásai (2019)
Proceedings of the 12th National Conference on Transportation Asset Management (2019)
Szerző(k): K.A. Zimmerman
Transportation ResearchBoard USA
Terjedelem: 111 oldal
Nearly 500 transportation asset management practitioners came together in San Diego, California, for the 12th National Conference on Transportation AssetManagement. The conference program was organized around the following five tracks:Track 1: Analyzing and Optimizing Investment Options, Track 2: Data Systems to Improve Decisions, Track 3: Implementation, Track 4: Organization and Workforce, Track 5: Setting the Course for Compliance and Beyond.
Közforgalmú közlekedési honnan-hová utazások felvételi módszerei és technológiái
Public Transit Rider Origin Destination Survey Methods and Technologies (2019)
Szerző(k): Zalewski, D.Sonenklar, A. Cohen, J.Kressner, G.Macfarlane
Transportation ResearchBoard USA
Terjedelem: 173 oldal
This synthesis provides an overview of the current state of practice regarding public transit rider origin–destination survey methods and technologies. The study presents a literature review and results of a survey of transit agencies that conduct all different types of rider surveys. Fifty-seven completed responses were received from the 67 agencies in the survey sample, a response rate of 86 percent. Case examples of five transit systems are provided; these present an in-depth analysis of various survey strategies and include two agencies that have leveraged passive data to complement or eliminate origin–destination surveys.This synthesis will assist all transit agencies that conduct origin–destination surveys; the report presents the reality and complexity of conducting this type of survey and will allow agencies to compare what they are currently doing with what others are doing, get ideas about what otherstrategies are possible, and make better decisions about surveying in the future.
3 dimenziós úttervezési modell költség-haszon elemzés
3D Highway Design Model Cost Benefit Analysis
Szerző(k): Mitchell, E.Gensib, S.Sadasivam, T. Day, J. Gustafson, J. Bartlett, T.Bonzelet
WSP Michigan Inc. USA
Terjedelem: 103 oldal
Since 2012, the Michigan Department of Transportation (MDOT) has progressively integrated 3D models into its project delivery processes as a reference information documents (RID) and initiated this research project to understand the viability of expanding the use of 3D models. The primary objectives of this research project were to research and evaluate construction costs to determine the return on investment (ROI), investigate and document contractor’s current practices of using RID 3D models, explore ways to streamline plan production by delivering contractual model elements, and conduct an analysis of potential and actual risk reductions associated with issuing 3D models. Researchers engaged with industry partners and MDOT construction staff to understand the current uses of RID 3D models, identify opportunities for improvements, and assess the perceived risk of elevating the 3D model to be contractual. Additionally, the researchers conducted a statistical analysis of historical data provided by MDOT for projects tracked between 2012 and 2016 to assess the effects of 3D models as RID on bids and change orders. The findings of the study were then used to make recommendations for improving processes including education, outreach, and training; multi-disciplinary collaboration; and a framework for implementing contractual 3D models for construction. In addition, quantifiable benefits and costs related to the use of 3D models were used to determine a 5-year ROI.
Besorolást segítő rendszer fejlesztése és demonstrációja összekapcsolt jármű technológiával
Development and Demonstration of Merge Assist System using Connected Vehicle Technology
Szerző(k): Hussain, Z. Peng, M.I. Hayee
University of Minnesota USA
Terjedelem: 51 oldal
One potential area to improve driver safety and traffic mobility is around merge points of two roadways, e.g., at a typical freeway entrance ramp. Due to poor visibility because of weather or complex road infrastructure, on many such entrance ramps, it may become difficult for the driver on the merging/entrance ramp to clearly see the vehicles travelling on the main freeway, making it difficult to merge. A fundamental requirement to facilitate many advance driver assistance systems (ADAS) functions including a merge assist system is to accurately acquire vehicle positioning information. Accurate position information can be obtained using either sensor-based systems (camera-based, radar, lidar) or global navigation satellite systems (GPS, DGPS, RTK). For these systems to work well for practical road and weather conditions, advanced techniques and algorithms are needed, which make the system complex and expensive to implement. In this research project, we propose a merge assist system by acquiring the relative positioning of vehicles using standard GPS receivers and dedicated short-range communication (DSRC) based vehicle-to-vehicle (V2V) communication. The DSRC-equipped vehicles travelling on the main freeway and on the entrance-ramp will periodically communicate their positioning information with each other. Using that information, the relative trajectories, relative lane, and position of all DSRC-equipped vehicles travelling on the main freeway will be calculated and recorded in real time in the vehicle travelling on the entrance ramp. Finally, a merge-time cushion will also be calculated, which could potentially be used to assist the driver of the ramp vehicle to safely merge into the freeway.