Nemzetközi szemle: December
Aszfalt próbatestek készítésének gyakorlata laboratóriumi teljesítmény vizsgálatokhoz
Practices for Fabricating Asphalt Specimens for Performance Testing in Laboratories
Szerző(k): J.E. Sias, E.V. Dave, L.M. McCarthy
University of New Hampshire, Villanova University USA
Terjedelem: 213 oldal
This synthesis documents procedures related to laboratory fabrication of asphalt performance test specimens at state departments of transportation (DOTs) and partner laboratories that conduct performance testing on behalf of DOTs. The synthesis provides examples of sampling procedures, as well as practices developed by DOTs and partner laboratories for improving consistency in fabricating performance test specimens. Information for this study was gathered through a literature review, a survey of state DOTs, a survey of partner laboratories that complete asphalt testing for state DOTs, and follow-up interviews with selected agencies. Five case examples provide additional information on asphalt testing practices.
Elsőbbség a jelzőlámpás irányításban: a jelenlegi gyakorlat
Transit Signal Priority: Current State of the Practice
Szerző(k): P. Anderson, M.J. Walk, C. Simek
Texas A&M Transportation Institute USA
Terjedelem: 117 oldal
Bus transit signal priority (TSP) is an important tool that increases bus speeds and reliability, thereby improving transit system efficiency and effectiveness. Transit agencies implement a wide variety of TSP strategies and parameters, and they report different levels of benefits from TSP implementations in various traffic conditions and right-of-way treatments (e.g., mixed versus dedicated guideway). Currently, only fragmented documentation exists on the TSP strategies and parameters in place at different agencies, and there has not been a systematic effort to understand the link between TSP strategies and parameters and the level of benefit realized. As agencies may have limited understanding of what strategies and parameters are in use in other jurisdictions and how these decisions tie to the benefits of TSP, it is difficult to weigh the benefits against the tradeoffs involved. This synthesis documents the current practice of transit systems’ use of TSP to meet the different objectives under diverse conditions. It provides an overview of TSP strategies and parameters, the resulting benefits, and an assessment of to what extent the disparity in benefits realized is driven by strategy and parameter choices.
A közúti közlekedési hálózati üzem dekarbonizálása Ausztráliában és Új-Zélandon
Decarbonisation of Road Transport Network Operations in Australia and New Zealand
Szerző(k): R. Palmer, C. de Stigter
(letölthető ingyenes regisztrációval)
Terjedelem: 40 oldal
There is a considerable focus on vehicle electrification as the primary driver of reducing greenhouse gas emissions in the roads sector. Austroads has commissioned the development of this Issues Paper to assess the specific relevance of the greenhouse gas emissions issue from the point of view of road transport network operations, to frame the role that road network transport operations play in supporting the state and national ambitions for emissions reduction, and identify network management levers for consideration by decision makers. The paper has been developed to help direct the Network Task Force’s knowledge sharing and future research program. The paper identifies the global climate trajectories and the Paris Agreement goal to limit temperature increase to no more than 1.5°C. It explores the Australia and New Zealand policy landscape and level of ambition. It analyses the contribution of transport and the road sector to greenhouse gas emissions in Australia and New Zealand and reviews opportunities for contributing to net zero emissions in the context of electric vehicle take-up. The paper highlights the need for a strategic rebalancing of priorities to include greenhouse gas emissions reduction as a key consideration in all road network transport operations thinking and decision, alongside road safety and transport network efficiency and productivity.
Utazási viselkedési változások a részben önvezető járművek használói körében
Travel Behavior Changes Among Users of Partially Automated Vehicles
Szerző(k): S. Hardman
The University of California Institute of Transportation Studies USA
Terjedelem: 30 oldal
Partially automated battery electric vehicles (BEVs) are being sold to and used by consumers. Estimates indicate that as of the end of 2019, there were over 700,000 Partially Automated Tesla Vehicles—the subject of this study—on the roads globally. Despite this, little research has been done to understand how they may be changing travel behavior. In this study, qualitative interviews with 36 users of Tesla BEVs with Autopilot were conducted. The goal of this was to understand how Autopilot is used, user experiences of the system, and whether the system has any impact on drivers’ travel behavior. The focus of the last of these aims was to determine whether Autopilot could cause or was causing an increase in vehicle miles traveled (VMT) among the study participants. Results from the interviews showed that partial automation leads to consumers travelling by car more and being more willing to drive in congested traffic. These changes are due to increased comfort, reduced stress, and increased relaxation due to the partial automation system, and because of the lower running costs of a BEV. The results also point to a need for further research of partially automated vehicles that are already on the market, as 11 of 17 reasons for increased VMT that have been identified in modeling studies of fully automated vehicles (not yet commercially available) applied to users of Autopilot.
Baleseti előrebecslés modellek és módszerek fejlesztése körforgalmakban
Development of Roundabout Crash Prediction Models and Methods
Szerző(k): E. Ferguson, J. Bonneson, L. Rodegerdts, N. Foster, B. Persaud, C. Lyon, D. Rhoades
Kittelson & Associates, Inc., Persaud and Lyon, Inc. , Canada, Write Rhetoric, USA
Terjedelem: 187 oldal
Safety performance factors (SPFs) and crash modification factors (CMFs) are predictive models that estimate expected crash frequencies. Transportation professionals use these models to identify locations where crash rates are higher than expected, to estimate safety benefits of a proposed project, and to compare the safety benefits of design alternatives. The models help identify and prioritize locations for safety improvements, compare project alternatives by their expected safety benefits, and guide detailed design decisions to optimize safety. Research indicates that roundabouts provide substantial reductions in crashes, especially crashes that result in serious injuries or fatalities. However, the 1st edition of the Highway Safety Manual (HSM) did not include a crash prediction method for roundabouts; therefore, practitioners were not able to quantitatively assess the crash reduction benefits of providing a roundabout at a specific intersection or to investigate the safety effects of complex design decisions at single lane and multilane roundabouts. NCHRP Report 888 provides practitioners with SPFs and CMFs for roundabouts. The models include variables for geometric features and operational characteristics, as well as their expected effects on crash rates for motorized and nonmotorized users. The models can be used for planning-level analysis, and, as a project develops and more detailed information is available, for analysis at the intersection level and leg level of an intersection.
Parkolási díjak, rendelkezésre állás, módválasztás és városalakítás
Parking Prices and Availability, Mode Choice and Urban Form
Szerző(k): S. F. Franco
Nova University of Lisbon. Portugal, The International Transport Forum, OECD
Terjedelem: 34 oldal
This paper provides evidence how parking reforms can help reduce car dependency and achieve a more efficient use of city space. It looks at how the price and availability of parking influence transport choices and urban form. It also investigates the effect of minimum parking requirements and regulations on developer decisions and land use. The paper draws primarily on evidence from Los Angeles County and the City of Los Angeles, California, in the United States.
Autonóm funkciók szükségessége a közútkezelők intelligens közlekedési rendszereiben. Jó és rossz példák az automatizáltság növelésére a közútkezelők ITS rendszereiben
Needs for autonomic functions in road operators’ ITS. Good and bad practices from increasing the automation of road operators’ ITS
Szerző(k): M. Niculescu, A. Blanco
ITS Romania, DGT Spain, European ITS Platform
Terjedelem: 50 oldal
This document is elaborated in the framework of Sub-activity 4.2 – Facilitating Automated Driving of the EU EIP project and is an updated and consolidated deliverable of the second and third deliverables of Task 4 – Autonomic road side ITS systems/Automation of road operator ITS. Task 4 will identify the requirements of automating the road operators´ ITS systems to facilitate automated vehicle – infrastructure integration. This includes the roadside ITS systems with properties like: self-maintenance, self-optimisation, self-management, and self-healing – fully or partly based on specific needs. Secondly, the task will identify good and avoidable practices in implementing automatic functions on roadside and traffic centre systems. Finally, the task also deals with the optimal automation level of traffic control/management/information centre operations and services. The scope of this deliverable is to describe what autonomic functions could benefit to road operators in improving their operations, maintenance and provision of ITS services. The document starts by describing the existing autonomic functions and systems and proposes a new approach in terms of architecture and the implementation of the autonomic applications.
Vízszintes ívek értékelési kézikönyve
Horizontal Curve Evaluation Handbook
Szerző(k): M.P. Pratt, S R. Geedipally, R.E. Avelar, M. Le
Texas A&M Transportation Institute, USA
Terjedelem: 80 oldal
Horizontal curves are a common and essential element of the rural highway system, and it is essential to sign and mark them consistently to minimize curve crash risk. Curve signing and marking consists primarily of conducting an engineering study to set the curve advisory speed, posting the advisory speed if necessary, and providing other signs and markings based on the curve severity. Additionally, curve safety can be addressed through more significant treatments such as installing a pavement friction treatment or even straightening the curve if the highway can be realigned. Over the past decade, the Texas Department of Transportation has sponsored several research projects to develop new procedures for setting curve advisory speeds on rural two-lane highways, examine crash frequency on rural highways in general, identify conditions when pavement friction treatments are beneficial and cost-effective, and extend curve advisory speed study methods to four-lane rural highways. This Handbook provides engineers and technicians with a consolidated source for applying all the preceding analysis tools to assess curve safety and implement needed treatments.