Nemzetközi szemle: Szeptember
Külsőségi egy sávos kétirányú utak időszakos alternatív forgalomirányítási módszereinek értékelése
Evaluation of Alternative Methods of Temporary Traffic Control on Rural One-lane, Two-way Highways
M. D. Finley, P. Songchitruksa, J. Jenkins Texas A&M Transportation Institute, USA
Terjedelem: 68 oldal
This report describes the methodology and results of analyses performed to identify and evaluate alternative methods for rural, one-lane, two-way temporary traffic control for maintenance operations. Researchers assessed the state-of-the-practice, conducted field studies, compared agency costs and benefits, and conducted a motorist delay analysis. Based on the findings of this research, the research team recommended that the Ohio Department of Transportation (ODOT) use red/yellow lens automated flagger assistance devices (AFADs) and portable traffic signals (PTSs), when appropriate, to control traffic approaching the one-lane section of a two-lane highway. AFADs are most suitable for short-term stationary operations that last a few hours up to one day. Due to their smaller size, AFADs are best suited for narrow roadways with limited to no shoulders. As the work duration increases, PTSs become a viable option. Due to the additional time it takes to deploy and setup PTSs, the work activity should last at least a half a day. Due to their larger size, PTSs are best suited for higher volume roadways with shoulders and relatively flat side slopes. Traditional flagging procedures should still be used at maintenance operations where these devices are not suitable due to work duration or other site/work characteristics.
Nagy mennyiségű adat a közlekedésben. Megértés és értékelési lehetőségek
Big Data and Transport. Understanding and assessing options
Ph. Crist International Transport Forum (OECD)
Terjedelem: 66 oldal
This report examines issues relating to the arrival of massive, often real-time, data sets whose exploitation and amalgamation can lead to new policy-relevant insights and operational improvements for transport services and activity. It is comprised of three parts. The first section gives an overview of the issues examined. The second broadly characterises Big Data, and describes its production, sourcing and key elements in Big Data analysis. The third section describes regulatory frameworks that govern data collection and use, and focuses on issues related to data privacy for location data.
Az útfelület egyenetlenségének hatása a jármű üzemi költségekre – irodalmi áttekintés
Literature review: The effect of pavement roughness on vehicle operating costs
M. M. Robbins, Nam Tran National Center for Asphalt Technology, USA
Terjedelem: 22 oldal
Ride quality as a measure of pavement roughness plays an important role in users’ level of comfort and operating costs. It is evident that rough pavements result in increased users’ costs through vehicle operating costs. This report is prepared based on a review of literature to further discuss the extent to which pavement roughness affects the various components of vehicle operating costs.
Korrózió figyelő rendszer meglévő vasbeton szerkezetekhez
A Corrosion Monitoring System for Existing Reinforced Concrete Structures
X. Shi, Z. Ye, A. Muthumani, Y. Zhang, J. F. Dante, H. Yu Western Transportation Institute, Montana State University, USA
Terjedelem: 87 oldal
This study evaluated a multi-parameter corrosion monitoring system for existing reinforced concrete structures in chlorideladen service environments. The system was fabricated based on a prototype concrete corrosion measurement system that had been built and patented by Southwest Research Institute (SwRI). In a laboratory benchmark test, a chloride concentration vs. potential calibration curve was established and indicated good linearity between 0.01 mol/L and 1 mol/L. The general and maximum localized corrosion rates, as measured by the Multielectrode Array Sensor (MAS) probe, were all sensitive to the incremental chloride concentration in a simulated pore solution. However, once active corrosion is initiated and a great amount of chloride is present, the MAS probe may no longer serve as a good tool to predict the corrosion rate of rebar unless more research is conducted to establish such prediction or correlation. It was also revealed that in a sensor longevity test, only a fraction of sensors can be considered reliable after eight accelerated weathering cycles.
Az időjárás, a közlekedési balesetek és a klímaváltozás
Weather, Traffic Accidents, and Climate Change
B. Leard and K. Roth Resources for the Future, University of California, USA
Terjedelem: 44 oldal
We exploit random daily variation in weather to document the relationship of temperature, rainfall, and snowfall with traffic accidents and travel demand. Using information on 46.5 million accidents from the State Data System of police reported accidents for 20 states and travel demand for 207,455 households included in the National Household Transportation Survey, we find unanticipated effects of weather on accidents and their severity. Our estimates suggest that while warmer temperatures and reduced snowfall are associated with a moderate decline in non-fatal accidents, they are also associated with a significant increase in fatal accidents. This increase in fatalities is due to a robust positive relationship between fatalities and temperature. Half of the estimated effect of temperature on fatalities is due to changes in the exposure to pedestrians, bicyclists, and motorcyclists as temperatures increase. The application of these results to middle-of-the-road climate predictions suggests that weather patterns for the end of the century would lead to 603 additional fatalities per year. Between
2010-2099, the present value social cost of all types of accidents caused by climate change is $58 billion.
Elválasztott kerékpársáv tervezési útmutató
Separated Bike Lane Planning and Design Guide
Federal Highway Administration, USA
Terjedelem: 148 oldal
This Separated Bike Lane Planning and Design Guide outlines planning considerations for separated bike lanes (also sometimes called “cycle tracks” or “protected bike lanes”) and provides a menu of design options covering typical one and two-way scenarios. It highlights different options for providing separation, while also documenting midblock design considerations for driveways, transit stops, accessible parking, and loading zones. It provides detailed intersection design information covering topics such as turning movement operations, signalization, signage, and on-road markings. Case studies highlight best practices and lessons learned throughout the document. The Guide consolidates lessons learned from practitioners designing and implementing separated bike lanes throughout the U.S. It attempts to capture the current state of practice, while still recognizing that our understanding of this facility type is still evolving and that there is a need for design flexibility. To encourage continued development and refinement of techniques, the guide identifies specific data elements to collect before and after implementation to enable future analysis across facilities in different communities. It identifies potential future research, highlights the importance of ongoing peer exchange and capacity building, and emphasizes the need to create holistic ways to evaluate the performance of a separated bike lane.
Az önmagukat vezető járművek közlekedésbiztonsága: általános korlátok és az útfelület megosztása a hagyományos járművekkel
Road Safety with Self-Driving Vehicles: General Limitations and Road Sharing with Conventional Vehicles
M. Sivak and B. Schoettle The University of Michigan Transportation Research Institute, USA
Terjedelem: 13 oldal
Self-driving vehicles are expected to improve road safety, improve the mobility of those who currently cannot use conventional vehicles, and reduce emissions. In this white paper we discuss issues related to road safety with self-driving vehicles. Safety is addressed from the following four perspectives: (1) Can self-driving vehicles compensate for contributions to crash causation by other traffic participants, as well as vehicular, roadway, and environmental factors? (2) Can all relevant inputs for computational decisions be supplied to a self-driving vehicle? (3) Can computational speed, constant vigilance, and lack of distractibility of self-driving vehicles make predictive knowledge of an experienced driver irrelevant? (4) How would road safety be influenced during the expected long transition period during which conventional and self-driving vehicles would need to interact on the road? The presented arguments support the following conclusions: (1) The expectation of zero fatalities with self-driving vehicles is not realistic. (2) It is not a foregone conclusion that a self-driving vehicle would ever perform more safely than an experienced, middle-aged driver. (3) During the transition period when conventional and self-driving vehicles would share the road, safety might actually worsen, at least for the conventional vehicles.
A tengelycsoport terhelések hatása a hajlékony útpályaszerkezet tervezésre
The Influence of Multiple-axle Group Loads on Flexible Pavement Design a letöltéshez ingyenes regisztráció szükséges
M. Moffatt Austroads, Australia
Terjedelem: 279 oldal
The current Austroads approach to assess the relative damaging effects of different axle groups on road pavements is by comparison of the peak static pavement deflection response under the axle groups. The assumption that deflection is the most appropriate indicator of pavement damage is open to question and is not consistent with the use of strains to calculate the performance of pavement materials. In response, research conducted has determined that, with regard to the fatigue damage of asphalt and cemented materials, the standard load for an axle group type is dependent upon the thickness and modulus of the asphalt and the underlying pavement structure. As a result, it is proposed that the mechanistic design procedure for flexible pavements not use the concept of standard loads, but rather that the procedure determines the pavement damage resulting from each axle load and each axle group within a traffic load distribution. An examination of the implications of pavement design outcomes in using this method determined that in general, reductions in both asphalt and cemented material thicknesses of up to 50 mm would result. The research also determined that the currently used standard loads for tandem, triaxle and quad-axle were appropriate for use with the current empirical procedures for the design of granular pavements with thin bituminous surfacings.