A közlekedésépítési szakterület mérnöki és tudományos folyóirata. ISSN 2064-0919
9. szám
2017. tavasz
9
Bejegyzés

Nemzetközi szemle: Október

Közúti infrastruktúra beruházások biztonsági előnyei

Safety Benefits of Highway Infrastructure Investments
Szerző(k):
D.W. Harwood, J.M. Hutton, Z.N. Hans, R.R. Souleyrette, M.A. Fields
MRI Global, Iowa State University, University of Kentucky
Terjedelem: 143 oldal

Investments in proven highway safety countermeasures have the potential to effectively reduce motor vehicle crashes and associated injuries and fatalities. The work presented in this report offers current knowledge on the crash reduction effectiveness of specific infrastructure improvements and quantifies the important role of highway infrastructure upgrades in improving traffic safety. Seven case studies of actual infrastructure improvement projects are presented to illustrate the crash reduction benefits that can be attained by highway agency action

 

Az ausztrál úttervezési előírások értékelése objektív biztonsági eredmények alapján

Verification of Austroads Road Design Criteria Based on Objective Safety Evidence
Szerző(k):
C. Jurewicz, T. Makwasha, N. O'Callaghan
Austroads Australia
Terjedelem: 55 oldal

This report provides a compendium of recent and robust evidence on the relationships between twenty key geometric design criteria and safety outcomes. The project critically reviewed quality research sources to identify crash modification factors (CMFs) for such road design criteria as horizontal curvature, lane and sealed shoulder widths, sag and crest design values and various longitudinal sight distance requirements. The review of findings by the Project Advisory Group, consisting of the Task Force members, largely resulted in verification of the current design criteria values as published in the Guide to Road Design Part 3: Geometric Design. The report highlights areas for further investigation to refine the current understanding or to enable economic appraisal of potential future changes. The study reviewed potential for detailed design applications of the Australian National Road Assessment Model (ANRAM) and Interactive Highway Safety Design Model (IHSDM) in Australia and New Zealand. The review found both to be feasible but requiring further adaptations.

 


A közútkezelő önvezető járműveket segítő főbb tevékenységeinek értékelése


Assessment of Key Road Operator Actions to Support Automated Vehicles
Szerző(k):
R. Huggins, R. Topp, L. Gray, L. Piper, B. Jensen, L. Isaac, S. Polley, S. Benjamin, A. Somers
Austroads Australia
Terjedelem: 83 oldal

Australian and New Zealand road agencies and operators are preparing for the introduction of Automated Vehicles (AVs). 'This report investigates the potential changes needed to the way road networks are managed to consistently support and optimise the outcomes from the introduction of AVs. The project reviewed international and local documents and initiatives and consulted a range of stakeholders to determine the emerging requirements for AVs to operate on public and private road networks (including urban and rural areas). The report captures key issues in three broad categories: physical infrastructure, digital infrastructure, road operations. The report concludes with high level guidance for road agencies and operators. There are obvious challenges in providing practical guidance to agencies in a still evolving and changing environment, and some of the guidance, although still relevant, may be beyond the purview of individual road operators.

 

A középső elválasztás kialakításának hatáselemzése a gyalogosok és kerékpárosok biztonságáért

Analyzing the Impact of Median Treatments on Pedestrian/Bicyclist Safety
Szerző(k):
L.. Zhang, H. Rabin, S. Ghader, A. Asadabadi, M. Franz, C. Xiong, J. Litchford
University of Maryland USA
Terjedelem: 50 oldal

To improve pedestrian/bicyclist safety, the Maryland Department of Transportation State Highway Administration (MDOT SHA) has identified several high-frequency pedestrian/bicyclist crash locations through the Pedestrian Roadway Safety Audit (PRSA) Program. Recognizing an over-representation of pedestrian crashes related to illegal mid-block crossings, various median treatments have been implemented at target locations. While these countermeasures are generally perceived as effective and beneficial, this study seeks to quantify their impact. The research team applied trend and statistical analyses to assess the effectiveness of installed safety countermeasures. To investigate public opinions on median treatments, on-site surveys of pedestrians, bicyclists, and local businesses were conducted at the identified study locations. Trend analysis showed that median treatments helped reduce rates of various types of crashes at treatment sites, while increased rates were observed at control sites. Statistical analysis showed that median treatments had a significant, positive effect on the reduction total number of crashes and fatalities. Results from the surveys showed that the public believed that treatments were effective at discouraging mid-block crossings. Statistical analysis, trend analysis, and survey results supported the effectiveness of median treatments in decreasing crash rates and saving lives.

 

Ausztrália hosszú távú burkolat viselkedés megfigyelési programja – Összegző jelentés 2015-16

Austroads LTPP/LTPPM Study - Summary Report 2015-16
Szerző(k):
L. Choummanivong, T. Martin
Austroads Australia
Terjedelem: 46 oldal

This report provides a summary of activities completed during 2015–16 for the Austroads long term pavement performance monitoring project. Austroads has funded the long-term pavement performance study since late 1994. The project monitors the structural and functional performance of in-service pavement test sites across Australia. The report presents a summary of the LTPP/LTPPM current conditions, performance trends over the monitoring period, a brief summary of the maintenance activities undertaken during the period and a proposed work plan for 2016–17.

 

Önvezető járművek tesztelésének irányelvei Ausztráliában

Guidelines for trials of automated vehicles in Australia
Szerző(k):
National Transport Commission Australia
Terjedelem: 24 oldal

The introduction of automated vehicles into Australia requires rapid advances in a number of key policy areas. The potential benefits of this technology are vast: improved road safety outcomes, increased mobility for an ageing population and people with a disability, as well as productivity and environmental efficiencies. Australia sits ready to embrace this new technology but first we need to know that these vehicles are safe to use. To that end, Australia’s transport ministers have endorsed an ambitious roadmap of reform that will facilitate the introduction of more automated vehicles on our roads. These guidelines represent the first step of the roadmap. Their purpose is to provide clarity to industry so that trials can take place across all states and territories. Vehicle manufacturers, technology developers, governments and other agencies submitted feedback on these guidelines. This consultation highlighted the importance of national consistency to encourage investment and support cross-border trials. By developing a single and nationally-agreed set of guidelines, we want Australia to become a global testbed for automated vehicles. The guidelines are designed to offer flexibility and to support different technologies and applications as they emerge. Rather than embed trial requirements in legislation, these guidelines provide a performance-based framework that supports innovation and gives certainty to governments and industry alike.

 

Gazdaságos és repedésmentes nagyteljesítményű beton az útburkolat és közlekedési infrastruktúra építésben

Economical and Crack-Free High-Performance Concrete for Pavement and Transportation Infrastructure Construction
Szerző(k):
K.H. Khayat, I. Mehdipour
Missouri University of Science and Technology USA
Terjedelem: 219 oldal

The main objective of this research is to develop and validate the behavior of a new class of environmentally friendly and cost effective high-performance concrete (HPC) referred to herein as Eco-HPC. The proposed project aimed at developing two classes of Eco-HPC for the following applications: HPC for pavement construction (Eco-Pave-Crete); HPC for bridge infrastructure construction (Eco-Bridge-Crete). The binder contents for these construction materials were limited to 320 kg/m3 (540 lb/yd3) and 350 kg/m3 (590 lb/yd3), respectively, in order to reduce paste content, cost, CO2 emissions, and shrinkage. Both Eco-HPC types were optimized to develop high resistance to shrinkage cracking as well as to secure high durability. Given the relatively low binder content, the binder composition and aggregate proportion were optimized based on the packing density approach to reduce the paste required to the fill the voids among aggregate particles. The optimized concrete mixtures exhibited low autogenous and drying shrinkage given the low paste content and use of various shrinkage mitigating strategies. Such strategies included the use of CaO-based expansive agent (EX), saturated lightweight sand (LWS), as well as synthetic or recycled steel fibers. Proper substitution of cement by supplementary cementitious materials (SCMs) resulted in greater packing density of solid particles, lower water/superplasticizer demand, and improved rheological and hardened properties of cement-based materials. A statistical mix design method was proposed and was shown to be effective in optimizing the aggregate proportioning to achieve maximum packing density. The synergistic effect between EX with LWS resulted in lower autogenous and drying shrinkage. For a given fiber content, the use of steel fibers recovered from waste tires had twice the flexural toughness of similar mixture with synthetic fibers. The optimized Eco-HPC mixtures had lower drying shrinkage of 300 μstrain after 250 days. The risk of restrained shrinkage cracking was found to be low for the optimized concrete mixtures (no cracking even after 55 days of testing). The results of structural performance of large-scale reinforced concrete beams indicated that the optimized Eco-Bridge-Crete containing ternary combination of 35% fly ash and 20% slag replacements and recycled steel fibers developed significantly higher flexural toughness compared to the MoDOT reference mixture used for bridge infrastructure applications.

 

Gyalogosok és kerékpárosok biztonsága – a 10. Egyetemi Közlekedési Központok kiemelt konferencia összefoglalása

Pedestrian and Bicycle Safety - Summary of the 10th University Transportation Centers Spotlight Conference
Szerző(k):
K.F. Turnbull
Transportation Research Board USA
Terjedelem: 128 oldal

The Transportation Research Board (TRB) hosted a conference entitled Pedestrian and Bicycle Safety at the Keck Center in Washington, D.C., in December 2016. The conference included plenary sessions focused on the role of policy and guidance, emerging and future technologies, behavior change, and equity. The conference attracted approximately 150 participants. Conference participants also had the opportunity to interact with poster authors and to discuss issues and areas for further research in six concurrent breakout sessions. Speakers in the closing plenary session highlighted the topics and research needs discussed in the breakout groups. These proceedings consist of presentation summaries from the plenary sessions and the six concurrent breakout sessions.

 

Változó jelzésképű sebességhatár kijelzők összefoglaló értékelése

Synthesis of Variable Speed Limit Signs
Szerző(k):
B. Katz, J. Ma, H. Rigdon, K. Sykes, Z. Huang, K. Raboy
Leidos, ToXcel, LLC, USA
Terjedelem: 100 oldal

Variable speed limit (VSL) systems utilize information on traffic speed, occupancy, and volume detection, weather, and road surface conditions to determine the appropriate speeds at which drivers should be traveling, given current roadway and traffic conditions. The use of VSL during less than ideal conditions, such as heavy traffic and adverse weather, can improve safety by decreasing the risks associated with traveling at speeds that are higher than appropriate for the conditions and by reducing speed variance in traffic. In addition, VSL can be used to dynamically manage speeds during planned (rush hour congestion) and unplanned (incidents) events. Used in conjunction with managed lanes and other active traffic management strategies, VSL can respond to downstream congestion to eliminate or delay bottlenecks and mitigate the possibility of crashes. Based on a comprehensive literature review along with agency interviews to gather information on existing, deactivated and planned VSL systems, this synthesis provides a comprehensive review of current practices on VSL operations, particularly experiences from deployments in the United States, and to identify successful and best practices from the following perspectives: planning and policy, design, deployment, and standards, operations and maintenance, and outcomes.

 

A városi tér átalakítása a közösségi közlekedés fejlesztésével - a 3V megközelítés

Transforming the Urban Space through Transit-Oriented Development The 3V Approach
Szerző(k):
S. Salat, G. Ollivier
The World Bank
Terjedelem: 268 oldal

Imagine a city that is more competitive, with higher-quality neighborhoods, lower infrastructure costs, and lower CO2 emissions per unit of activity. This city has lower combined transportation and housing costs for its residents than other cities at similar levels of economic activity. Its residents can access most jobs and services easily through a combination of low-cost public transport, walking, and cycling. Its core economic and population centers are resilient to natural hazards. It is able to finance improvements to public space, connectivity, and social housing by capturing value created through integrated land use and transport planning. Such a vision has never been more relevant for rapidly growing cities than it is today. Transit-oriented development (TOD) can play a major role in achieving such a vision. It is a planning and design strategy to achieve compact, mixed-use, pedestrian and bicycle-friendly urban development closely integrated with transit stations. It embraces the idea that locating amenities, employment, shops, and housing around transit hubs promotes the use of public transit and non-motorized travel. Well-planned TOD at the city level is inclusive, because it focuses on ensuring access to jobs for all social groups through public transit. Based on an observation of methodologies applied in different countries, the World Bank’s Community of Practice on Transit Oriented Development has developed a methodology called the 3 Value (3V) Framework, which considers the node, place, and market potential value of each station. This book provides examples of approaches taken by cities like London and New York to align their economic, land use, and transport planning to generate jobs and high value. It illustrates the application of the 3V Framework in reviewing plans for the city of Zhengzhou, in China.

 


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