Nemzetközi szemle: December
A megelőző fenntartás szerepe a pályaszerkezet tervezésben és elemzésben
Consideration of Preservation in Pavement Design and Analysis Procedures
Applied Pavement Technology, Inc., USA
Terjedelem: 71 oldal
This report presents information on the effects of preservation on pavement performance and service life and describes three different approaches for considering these effects in pavement design and analysis procedures. These approaches could serve as a basis for developing procedures for incorporating preservation in the AASHTO Mechanistic-Empirical Pavement Design Guide: A Manual of Practice (MEPDG) and the AASHTOWare Pavement ME Design software. One of these approaches accounts for all aspects of structural and functional performance associated with the application of preservation treatments. Another approach builds off of the calibration/validation process outlined in the AASHTO Local Calibration Guide by collecting extensive time-series performance data from a substantive set of preservation-treated test sections to support the development of calibrated models. A third approach considers the immediate and long-term changes in materials and structure properties resulting from treatment application, although it involves a high level of complexity to accurately define these changes.
Az elmaradt közlekedési beruházások gazdasági és fejlesztési hatásai
Economic and Development Implications of Transportation Disinvestment
C. Duncan, G. Weisbrod Economic Development Research Group, Inc., USA
Terjedelem: 70 oldal
As demand for transportation facilities outstrips our ability to provide new facilities or even maintain existing ones, decision makers are faced with hard choices. They must critically examine the most efficient use of transportation facilities and how to prepare for investment or disinvestment over time. This study focuses on macroeconomic effects, intermodal tradeoffs, and methods for broadly informing disinvestment decision making in an era of constrained resources. The study examines methods available to estimate disinvestment effects on transportation system integrity within and across modes in urban areas, regionally, and in non-metro areas, and the use of those methods by transportation agencies. This includes economic forecasting and travel demand models, risk or probability models, needs models, and benefit and impact models. Information for this report was gathered through a survey of state departments of transportation, a literature review, and interviews with transportation officials. Seven case examples illustrate different disinvestment scenarios.
Útfelület minősítési technológiák értékelése
Evaluating Roadway Surface Rating Technologies Szerző(k):
B. Belzowski, A. Ekstrom The Regents of the University of Michigan, USA
Terjedelem: 65 oldal
The key project objective was to assess and evaluate the feasibility and accuracy of custom software used in smartphones to measure road roughness from the accelerometer data collected from smartphones and compare results with PASER (Pavement Surface and Evaluation Rating System) and IRI (International Roughness Index) measurement values collected from the same roadway segments. This project is MDOT’s first large implementation of a customized Android smartphone to collect road roughness data using a methodology developed from previous research work performed by UMTRI. Accelerometer data collection was performed via Android-based smartphones using a customized software application called DataProbe. The results are promising when considering the near term application of the DataProbe technology for smaller locales that drive over their local roads more often, generating web-based road roughness visuals of each of the roads in their jurisdiction.
Intelligens hálózati forgalmi folyam optimálás (INFLO), dinamikus sebesség harmonizálás és torlódásra figyelmeztetés prototípusának műszaki jelentése
Technical Report on Prototype Intelligent Network Flow Optimization (INFLO) Dynamic Speed Harmonization and Queue Warning Szerző(k):
D. Stephens, T. Timcho, T. Smith, K. Balke, H. Charara, S. Sunkari Battelle Memorial Institute, Texas A&M Transportation Institute, USA
Terjedelem: 125 oldal
This Technical Report on Prototype Intelligent Network Flow Optimization (INFLO) Dynamic Speed Harmonization and Queue Warning is the final report for the project. It describes the prototyping, acceptance testing and small-scale demonstration of the INFLO Prototype Speed Harmonization (SPD-HARM) and Queue Warning (Q-WARN) applications. This report also describes the programmatic and technical accomplishments of the program wherein the Small-Scale Demonstration fully confirmed the functionality of the INFLO Prototype System in an operational highway traffic environment. The system was proven to reliably capture current location and telematics data from connected vehicles and vehicle speed data from infrastructure; analyze the data to detect congestion and determine the beginning and end of congestion queues; formulate speed harmonization recommendations; communicate queue location and speed harmonization recommendations to drivers. The demonstration proved connected vehicle data capture and dissemination functionality using both cellular communications and DSRC communications. Furthermore, the Small-Scale Demonstration confirmed that the INFLO Prototype System has the latency and processing speed to support INFLO application functionality in an operational traffic environment.
Vízáteresztő burkolatok hideg klímában: áttekintés és hideg klíma esettanulmányok
Permeable Pavements in Cold Climates: State of the Art and Cold Climate Case Studies Szerző(k):
P. T. Weiss, M. Kayhanian, L. Khazanovich, J. S. Gulliver University of Minnesota, USA
Terjedelem: 375 oldal
This document is an extensive review of full-depth permeable pavements including porous asphalt, pervious concrete, and permeable interlocking concrete pavers (PICP). Also included is a brief section on articulated concrete blocks/mats. The main topics, which have been divided into chapters, include structural and mix design, hydrologic design, hydraulic performance (i.e. infiltration capacity), maintenance needs/frequency/actions, the impact of permeable pavement on water quality, results of a highway shoulder feasibility study, knowledge gaps, and several cold climate case studies from the United States and Canada. While progress has recently been made with the relatively new permeable pavement technology, researchers have also identified many unresolved issues that are not well understood. These include a methodology to measure subgrade infiltration rates, filling data gaps related to structural integrity, construction, and related issues associated with permeable pavements, determining what maintenance activities are most effective on various pavement types and how frequently specific maintenance actions should be performed, a better understanding of the processes involved in the observed reduction of contaminant concentrations in storm water flowing through permeable pavements, and a better understanding of the performance of permeable pavements over a time frame that better corresponds with a life-span of 20 years.
Sűrűség alapú összehangolt felhajtás szabályozási stratégia telepítése, tesztelése és finomítása
Field Implementation, Testing, and Refinement of Density Based Coordinated Ramp Control Strategy Szerző(k):
J. Hourdos, N. Geroliminis, S. Zitzow, and Y. S. Limniati University of Minnesota, USA
Terjedelem: 142 oldal
In the Twin Cities metropolitan area, freeway ramp metering goes back as early as 1969, when the Minnesota Department of Transportation (MnDOT) first tested ramp metering in an I-35E pilot project. To date, the Twin Cities ramp metering system has grown to include more than 433 ramp meters. Research on better, improved ramp control strategies has continued over the years and MnDOT has implemented minor and major changes in the control logic. Two independent studies both aimed at developing the next generation in ramp metering by focusing on density. Based on these efforts, two new algorithms were developed: the UMN Density and the UMD KAdaptive, named based on the campus at which they were developed. The goal of this project was to implement both algorithms and test them under real conditions. Priorities and technical problems prevented the evaluation of the UMN algorithms, so this report focuses on the evaluation of the UMD KAdaptive algorithm on two freeway corridors in the Twin Cities, MN. The first site, a section of TH-100 northbound between 50th Street and I-394, was selected to compare the then current logic, the Stratified Zone algorithm, with the new one. During the course of this project, the UMD algorithm eventually replaced the Stratified Zone algorithm and was implemented in the entire system. This full deployment also included corridors that were not controlled before. The second evaluation site on eastbound TH-212 was a site that allowed for a with/without control evaluation of the UMD algorithm. This report describes the experiments conducted at both sites and includes a comprehensive review of the state of ramp metering strategies around the world to date.
Javított híd leromlási modellek, előrebecslő eszközök és költségek
Improved Bridge Deterioration Models, Predictive Tools and Costs a letöltéshez ingyenes regisztráció szükséges
R. Kotze, H. Ngo, J. Seskis Austroads, Australia
Terjedelem: 132 oldal
The management of Australia and New Zealand’s bridge stock involves the development of forward works programs for periods up to, and longer than, ten years into the future. The scheduling of maintenance, rehabilitation and replacement, forms part of these forward works programs; however, it is often difficult to estimate when these costs will be incurred and plan accordingly. Bridge deterioration modelling and prediction tools have the potential to improve the scheduling of maintenance and replacement works for bridges. In this report, state-of-the-art deterioration modelling techniques are reviewed highlighting the advantages and limitations of each approach. The findings indicate that currently deterioration modelling is potentially difficult to implement in the Australian and New Zealand context, given the lack of integration of the data sets with existing bridge asset management tools. Based on the results of a comprehensive survey of Australian and New Zealand road agencies, the status quo regarding bridge asset management practices is discussed and evaluated. This includes the number of condition states, inspection frequency, structural inventory classification, and the collection of environmental data and historical cost data. In addition, issues such as intervention levels, utilisation of condition data, quality assurance and quality control of inspection data and engineering judgement were also reviewed. The report identifies differences in approaches between member road agencies and makes recommendations regarding minimum data sets required for deterioration modelling. A vision statement which covers the specific issues that need to be progressed has been developed to assist road agencies to work together towards harmonized common goals for inspection practise, inventory information and bridge management approach. The achievement of this vision will enable the development and implementation of a national deterioration model for bridge asset management.
Valós idejű algoritmus a rugalmas gépkocsi megosztási rendszerben a személyek közötti utazás egyeztetés megoldására
A Real-Time Algorithm to Solve the Peer-to-Peer Ride-Matching Problem in a Flexible Ridesharing System
N. Masoud, R. Jayakrishnan University of California, USA
Terjedelem: 27 oldal
Real-time peer-to-peer ridesharing is a promising mode of transportation that has gained popularity during the recent years, thanks to the wide-spread use of smart phones, mobile application development platforms, and online payment systems. An assignment of drivers to riders, known as the ride-matching problem, is the central component of a peer-to-peer ridesharing system. In this paper, we discuss the features of a flexible ridesharing system, and propose an algorithm to optimally solve the ride-matching problem in a flexible ridesharing system in real-time. We generate random instances of the problem, and perform sensitivity analysis over some of the important parameters in a ridesharing system. Finally, we introduce the concept of peer-to-peer ride exchange, and show how it affects the performance of a ridesharing system.