A közlekedésépítési szakterület mérnöki és tudományos folyóirata. ISSN 2064-0919
10. szám
2017. ősz

Nemzetközi szemle: December

A késleltetett fenntartás következményei az útvagyonra nézve (részletes mellékletekkel az egyes vagyonelemek szerint:
burkolatok, hidak, átereszek, korlátok, világítás, jelek, jelzések)

Consequences of Delayed Maintenance of Highway Assets
C.M. Chang, S. Nazarian, M. Vavrova, M.T. Yapp, L.M. Pierce, W. Robert, R.E. Smith
The University of Texas at El Paso, Nichols Consulting Engineers, Chtd. Spy Pond Partners, LLC, College Station, TX, USA
Terjedelem: 82 oldal

The consequences of delayed maintenance usually are underestimated, or not fully considered, in the asset management process. One major reason for this is the lack of a practical framework and procedures to objectively quantify these consequences. The objective of NCHRP Project 14-20A, “Consequences of Delayed Maintenance of Highway Assets,” was to develop a set of procedures for quantifying the consequences of delayed maintenance of highway assets. The research study was divided into two phases. In Phase I, a general framework was developed and applied to prepare procedures for pavements and bridges. The general framework involves three main steps: define the asset preservation policy; determine maintenance and budget needs; and conduct analyses of delayed maintenance scenarios. In Phase II, procedures for culverts, guardrails, lighting, pavement markings, and highway signs were prepared. The procedures describe the processes, methods, and analytical tools to assist agencies in making better-informed investment decisions for the preservation of the highway system.


Városi motorkerékpáros tervezési kézikönyv

Urban Motorcycle Design Handbook
Transport for London, UK
Terjedelem: 31 oldal

Motorcyclists are a unique road user group with specific characteristics. Motorcycles are very manoeuvrable, but their distinctive grip and balance requirements in combination with a range of other factors mean that they are at a higher risk of being involved in a collision. The Urban Motorcycle Design Handbook sets out the key highway design requirements for motorcycle safety in London and has been developed with valuable input from stakeholder groups. Using this Handbook will lead to a better understanding of how road and traffic conditions affect motorcyclists and how risks can be reduced and hazards minimised for this vulnerable road user group. The key design issues for motorcyclists are: factors affecting grip, issues around visibility, road-side features, traffic calming, filtering. The aim of this handbook is to enhance understanding of the issues for all concerned with the planning, design, construction, operation and maintenance of London’s streets or with any schemes that affect the highway.


Torlódásra figyelmeztető rendszer fejlesztése aktív forgalomirányító eszközökkel

Development of a Queue Warning System Utilizing ATM Infrastructure
J. Hourdos, Z. Liu, P. Dirks, H.X. Liu, S. Huang, W. Sun, L. Xiao
University of Minnesota USA
Terjedelem: 86 oldal

MnDOT has already deployed an extensive infrastructure for Active Traffic Management (ATM) on I-35W and I-94 with plans to expand on other segments of the Twin Cities freeway network. The ATM system includes intelligent lane control signals (ILCS) spaced every half mile over every lane to warn motorists of incidents or hazards on the roadway ahead. This project developed two separate systems that can identify lane-specific shockwave or queuing conditions on the freeway and use existing ILCS to warn motorists upstream for rear-end collision prevention. The two systems were field tested at two locations in the ATM equipped network that have a high frequency of rear-end collisions. These locations experience significantly different traffic-flow conditions, allowing for the development and testing of two different approaches to the same problem. The I-94 westbound segment in downtown Minneapolis is known for its high crash rate due to rapidly evolving shockwaves while the I-35W southbound segment north of the TH-62 interchange experiences longstanding queues extending into the freeway mainline. The Minnesota Traffic Observatory developed the I-94 Queue Warning system while the University of Michigan, under contract, developed the I-35W system. Prior to the I-94 installation, based on data collected in 2013, there were 11.9 crashes per VMT and 111.8 near crashes per VMT. In the first three months of the system’s deployment, event frequency reduced to 9.34crashes per million vehicle miles of travel (MVMT) and 51.8 near crashes per MVMT, a 22% decrease in crashes and a 54% decrease in near crashes. The I-35W system did not undergo a similarly thorough evaluation, but for most of the lane segments involved, it showed that queue warning messages help reduce the speed variance near the queue locations and the speed difference between upstream and downstream locations. This also implicated a satisfactory level of compliance rate from travelers.


Nagy modulusú aszfaltbeton keverékek felhasználása alaprétegként

High-Modulus Asphalt Concrete (HMAC) Mixtures for Use as Base Course
F. Leiva-Villacorta, A. Taylor, R. Willis
National Center for Asphalt Technology at Auburn University, National Asphalt Pavement Association, USA
Terjedelem: 61 oldal

Recent studies on long-life flexible pavements indicate that it may be advantageous to design and construct asphalt mixtures comprising the underlying layers in such a manner that very high modulus mixtures are produced. The French have been experimenting with and designing pavements with high-modulus bases since the 1980s. This study considered the engineering properties of asphalt mixtures produced using a European specification for high-modulus asphalt concrete (HMAC) mixtures and used as base course. This specification includes volumetric requirements such as asphalt content and air voids, but there are also requirements for engineering parameters that address performance requirements such as rutting and fatigue cracking. The purpose of this study was to investigate the design of asphalt mixtures having higher modulus. The study was limited to a laboratory performance evaluation and a theoretical modeling component where the results were used to indicate potential field performance. A comprehensive literature study was performed to assess the current state-of-the-practice on HMAC mixture design, pavement design, laboratory performance tests, and full scale pavement performance. The experimental plan included a variety of mixtures with different material and binders such that higher moduli were obtained compare to conventional mixtures. The plan included a French mixture with a stiff binder (PG 88-16), two mixtures containing 35% RAP both with polymer-modified binders but one high polymer content (HiMA), another mixture containing 25% RAP and 5% RAS with a polymer-modified binder, and finally, a 50% RAP mixture with a polymer-modified binder. The laboratory testing program evaluated binder performance grade, mixture stiffness over a wide temperature range, fatigue cracking, and permanent deformation. In addition, AASHTOWare Pavement ME Design software was used to determine how a high-modulus base would affect predicted performance of asphalt pavements. The results of this study indicated that European mix design standard methods and specifications were successfully implemented on local (U.S.) virgin and recycled materials. In addition, increased stiffness of high modulus mixtures improves mechanistic-empirical predicted performance of pavement in rutting, fatigue cracking, and ride quality. However, it was determined that performance of new materials cannot be reliably modelled with the current transfer functions and further field validation is required.


Önvezető járművek biztonságos közlekedését segítő szabályozási lehetőségek Ausztráliában

Regulatory options to assure automated vehicle safety in Australia
National Transport Commission Australia

Terjedelem: 112 oldal

Automated vehicles that do not require human driver input into the driving task for at least part of the journey are expected to arrive on our roads from around 2020. Currently there is no explicit regulation covering these automated driving functions. Manufacturers are aiming to ensure automated driving functionality improves road safety, but this technology may also create safety risks for road users.
The purpose of this paper is to seek feedback on: whether there is a need for explicit regulation of automated driving functions, above existing transport and consumer law, if there is a need for regulation, what form this should take. We are seeking feedback from governments, road safety experts, automated vehicle manufacturers, technology providers, insurers and other stakeholders on these questions. This paper examines: how safety of automated vehicle functions should be assessed; the options for a safety assurance system; the criteria that should be used to decide among those options; institutional arrangements, road access and compliance.


Önvezető járművek szimpózium 2016. Összefoglalás

Automated Vehicles Symposium 2016 Summary
Transportation Research Board USA
Terjedelem: 206 oldal

This report presents the proceedings from the 2016 Automated Vehicle Symposium (AVS) held in San Francisco, California. The 2016 AVS provided the opportunity for communication, collaboration, and information sharing on a wide range of topics, including potential public policy, safety and security, ethics, and equity concerns, as well as technology innovations and applications. The report follows the general symposium agenda. The presentations by speakers in the general sessions are summarized including the keynote addresses and the highlights from the 22 breakout sessions.


Kerékpáros létesítmények forgalmi hatásai

Traffic Impacts of Bicycle Facilities
J. Hourdos, D. Lehrke, M. Duhn, A. Ermagun, L. Singer-Berk, G. Lindsey
University of Minnesota USA
Terjedelem: 100 oldal

Engineers need information about interactions between vehicles and bicyclists to design efficient, safe transportation systems. This study involved a review of design guidelines for bicycle facilities, observation of bicycle-vehicle interactions at nine roadways with different types of bicycle facilities, analysis of results, and description of design implications. Facilities observed included buffered and striped bicycle lanes, sharrows (painted lane markings - i.e., bicycles and arrows - indicating lane is shared), signed shared lanes, and shoulders of various widths. Driver behaviors were categorized as no change in trajectory, deviation within lane, encroachment into adjacent lane, completion of a passing maneuver, and queuing behind cyclists. Drivers on roadways with bicycle lanes were less likely to encroach into adjacent lanes, pass, or queue when interacting with cyclists than drivers on roadways with sharrows, signs designating shared lanes, or no bicycle facilities. Queueing behind cyclists, the most significant impact on vehicular traffic flows, generally was highest on roads with no facilities or shared facilities without marked lanes. Statistical modeling confirmed the descriptive results. Given an objective of increasing predictability of driver behavior, buffered or striped bicycle lanes offer advantages over other facilities. Sharrows may alert drivers to the presence of cyclists, but traffic impacts on roadways with sharrows may not differ significantly from roadways with no facilities. Signs indicating bicyclists may occupy lanes also may alert drivers to the presence of cyclists, but this study provided no evidence that interactions on roadways marked only with signs differ from roadways with no facilities. From the perspective of reducing potential traffic impacts, bicycle lanes are to be preferred over sharrows or signage.


Nagy modulusú magas fáradási ellenállású aszfalt (EME2) technológia transzfer: zárójelentés

High Modulus High Fatigue Resistance Asphalt (EME2) Technology Transfer: Final Report
M. Dias, Laszlo Petho, E. Denneman, A. Beercroft
Austroads Australia
Terjedelem: 55 oldal

EME2 mixes are produced using a hard paving grade bitumen applied at a high binder content (approximately 6%). Compared to conventional asphalt bases with unmodified binders, EME2 asphalt is characterised by high stiffness, high durability, superior resistance to permanent deformation and good fatigue resistance. International and Australian experience indicates that significant pavement thickness reductions can be achieved using EME2. The purpose of this project was to assist industry in the successful transfer of French Enrobés à Module Elevé Class 2 (EME2) technology to Australia. EME2 technology offers the prospect of reduced asphalt thicknesses for heavy duty pavements, and lower construction and maintenance costs. TT1908 was a three-year Austroads project, and this report summarises the outcomes of the final year of the study. As part of the project, an Australian specification framework for EME2 mixes was developed and the requirements for manufacturing, paving and compliance were also provided. Demonstration trials were also carried out as part of the validation process. The final EME2 mix design specification limits are provided and discussed in this report.


Beton hídelemek repedéseinek szabályozása

Control of Concrete Cracking in Bridges
H. G. Russell
Henry G. Russell, Inc. USA
Terjedelem: 115 oldal

Cracking of concrete in bridges continues to be a concern for bridge owners, particularly with bridge decks exposed to severe environments. The control of cracking for aesthetic, durability, and structural reasons becomes increasingly important as service-life goals are extended and higher-strength concrete, higher-strength reinforcement, and different types of reinforcement are used in bridge construction. This study provides information on methods used to control concrete cracking in bridge superstructures and substructures, and on the influence of cracking on long-term durability. The study found that no single best practice can be used to enhance concrete bridge deck performance. Useful practices include reducing drying shrinkage of the concrete mix; reducing temperature differences; nighttime concrete placements; and the use of supplementary cementitious materials, internal curing, shrinkage-reducing admixtures, or shrinkage compensating concrete. Wet curing of concrete decks beginning immediately after concrete finishing and continuing for at least 7 days, followed by the application of a curing compound, was identified as an appropriate construction practice for concrete bridge decks. For prestressed concrete beams, end zone cracking can often be prevented by revising the detensioning sequence. Cracking in concrete substructures was of less concern than in superstructure components.


Az EU közúti biztonsági haladásának értékelése. A 11. Közúti Biztonsági Teljesítmény Index jelentés

Ranking EU Progress on Road Safety. 11th Road Safety Performance Index Report
D. Adminaite, G. Jost, H. Stipdonk, H. Ward
European Traffic Safety Council
Terjedelem: 40 oldal

Since 2014, progress has virtually ground to a halt. 2016 was the third consecutive poor year for road safety: 25,670 people lost their lives on EU roads compared to 26,200 the previous year - a 2% decrease. But this followed a 1% increase in 2015 and stagnation in 2014. Out of the 32 countries monitored by the PIN Programme, 15 countries registered a drop in the number of road deaths last year (Fig.1). The best results were achieved in Lithuania with a 22% reduction, Cyprus with 19%, the Czech Republic with 17%, Latvia with 16% and Switzerland with 15%. As many as 15 countries saw an increase while progress stood still in two countries.



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