Nemzetközi szemle: Szeptember
A sebesség és a baleseti kockázat
Szerző(k): International Transport Forum
Terjedelem: 82 oldal
This study aims to document objectively the relationship between vehicle speed and crash risks. It assesses to what extent recent changes in speed limits or the wide-scale introduction of automated speed enforcement have moderated actual average speeds, and whether this has delivered the safety impacts that theoretical models of the relationship between speed and crashes suggest. The cases analysed come from ten countries: Australia, Austria, Denmark, France, Hungary, Israel, Italy, Norway, Sweden and the United States. The report was prepared by the ITF’s permanent working group on road safety, the International Traffic Safety Data and Analysis Group (IRTAD).
Gyalogosok biztonságának javítási útmutatója szabályozatlan keresztezési helyszíneken
Szerző(k): Blackburn, C. Zegeer, K., Brookshire VHB, Austria, University of North Carolina, USA
Terjedelem: 41 oldal
This guide assists State or local transportation or traffic safety departments that are considering developing a policy or guide to support the installation of countermeasures at uncontrolled pedestrian crossing locations. This document provides guidance to agencies, including best practices for each step involved in selecting countermeasures. By focusing on uncontrolled crossing locations, agencies can address a significant national safety problem and improve quality of life for pedestrians of all ages and abilities. Agencies may use this guide to develop a customized policy or to supplement existing local decision-making guidelines.
Mobil eszközök mintájának felhasználása a forgalomnagyság becslésére
Szerző(k): Turner, P. Koeneman, Texas A&M Transportation Institute USA
Terjedelem: 26 oldal
In this project, TTI worked with StreetLight Data to evaluate a beta version of its traffic volume estimates derived from global positioning system (GPS)-based mobile devices. TTI evaluated the accuracy of average annual daily traffic (AADT) volume estimates as well as average annual hourly volume (AAHV) estimates from Streetlight Data using actual volume counts from MnDOT traffic monitoring sites. Traffic volume estimation from mobile devices has potential, but analytic enhancements are needed to improve accuracy and granularity of estimated traffic volumes. Some of the AADT volume estimates from StreetLight Data were within acceptable error ranges (10% to 20% absolute percent error), but other estimates were significantly outside this acceptable error range (greater than 100% absolute percent error). Lower volume roadways had the highest errors, presumably due to lower mobile device sample sizes. The AAHV evaluation results at 12 non-public MnDOT sites reinforce the need for analytic improvements, as these results showed higher error (49% mean absolute percent error) than the results at the 69 public permanent sites (39% mean absolute percent error).
Dinamikus tengelyterhelés mérés érzékelő és szabályozó egységek működésének és teljesítményének összehasonlítása
Weigh-in-Motion Sensor and Controller Operation and Performance Comparison
Szerző(k): Gupta, X. Tang, L. Yuan, University of Minnesota USA
Terjedelem: 127 oldal
This research project utilized statistical inference and comparison techniques to compare the performance of different Weigh-in-Motion (WIM) sensors. First, we analyzed test-vehicle data to perform an accuracy check of the results reported by the sensor-vendor Intercomp. The results reported by Intercomp mostly matched with our own analysis, but the data were found to be insufficient to reach any conclusions about the accuracy of the sensor under different temperature and speed conditions. Second, based on the limited data from the Intercomp and IRD sensor systems, we performed tests of self-consistency and comparisons of measurements to inform the selection of a superior system. Intercomp sensor data were found to be not self-consistent but IRD data were. Given the different measurements provided by the two sensors, without additional data, we were not able to reach a conclusion regarding the relative accuracy or the duration of consistent observations before needing recalibration. Initial comparisons indicated potential problems with the Intercomp sensor. We then suggested alternate approaches that MNDOT could use to determine whether recalibration was required. Finally, we analyzed ten-month data from the IRD WIM system and four-month data from the Kistler WIM system to evaluate relative sensor accuracy. While both systems were found to be self-consistent within the data time frame, the Kistler system generated more errors than the IRD system. Conclusions regarding relative accuracy could not be reached without additional data. We identified the sorts of measurements that would need to be monitored for recalibration and the methodology needed for estimating future recalibration time.
Útállapot helyreállítási idejét becslő rendszer fejlesztése téli havas helyzetekre
Szerző(k): Kwon, C. Park, University of Minnesota USA
Terjedelem: 268 oldal
This research develops a Normal Condition Regain Time (NCRT) estimation system, which automatically determines the NCRT at detector stations on the metro-freeway network for given snow events. The NCRT process is based on the findings that the speed level during the recovery process reaches a stable free-flow-speed (FFS), whose value is generally lower than the pre-snow FFS at a same location. Further, the speed-density (U-K) relationship of the traffic flow after snow is cleared exhibits a similar but shifted-down pattern of the normal-day U-K relationship at a given location. In this study, the after-snow traffic condition with a stable but shifted-sown pattern of the normal-day U-K relationship is defined as the ‘wet-normal’ condition, and the NCRT is defined as the time when the U-K data during a snow event starts to follow the wet-normal U-K pattern at a given station. The NCRT estimation system first collects the traffic and weather data for the metro-freeway network and determines the normal-day U-K relationships for the detector stations whose traffic data include both uncongested and congested regions. The normal-day U-K relationships are then applied to calibrate the wet-normal U-K patterns at given locations using the traffic data collected during snow events. Finally, the NCRTs are determined for each station by comparing the U-K data trajectory during a given event with the wet-normal U-K pattern at given locations. The NCRT estimation system has been applied to a set of the sample snow events.
Közúti üzemi berendezések optimális újra beszerzési ciklusa
Szerző(k): Hamilton, Transportation Research Board USA
Terjedelem: 179 oldal
This report presents the results of a study to develop a Guide for Optimal Replacement Cycles of Highway Operations Equipment (Guide). The report summarizes pertinent literature on equipment replacement methodologies as it relates to highway operations equipment and provides an overview of the Guide and replacement optimization analysis tool developed in the project. The Guide identifies the factors relevant for determining optimal replacement cycles using life-cycle cost analysis, describes the data and information needed to perform equipment life-cycle cost analysis, and presents the approaches and processes involved in equipment replacement decisions. The Guide outlines a systematic process for determining replacement needs, identifying candidate equipment units for replacement, and preparing an annual equipment replacement program. The process contained in the Guide applies to all types of highway operations equipment, both on- and off-road. The optimization tool is used to perform life-cycle cost analysis and support the replacement processes. A User Manual is provided for the optimization tool and includes step-by-step instructions for its use.
Hálózati és vagyon gazdálkodás: a valós idejű adatok előnyei
Szerző(k): Harris, R. Hyde, D. Smith, Abley Transportation Consultants Limited, New Zealand
Terjedelem: 83 oldal
Data is essential for understanding the demands placed on road assets and transport networks. There is an opportunity through advances in real-time technologies to improve the delivery of network management and asset management activities. This requires an understanding of both the real-time technologies that are available, and the real-time information needs of network managers and asset managers. This research investigated the applications of real-time technologies and data in asset and network management. This included identifying a range of opportunities for expanding the use of real-time technology, for example by making better use of existing datasets and improving the detection of incidents and defects. A range of challenges were also identified, including the difficulties of working with ‘big’ real-time datasets, the risk of reliance on technology and the need for specialist expertise to develop real-time applications. The outputs of this research include a range of recommendations, including possible real-time technology applications and actions to ensure the transport industry keeps up to date with advances in sensor technologies, analytical platforms and communication networks.
Sebességhatár csökkentés a biztonságosabb SCRIM csúszásellenállás mérés érdekében
Szerző(k): Cenek, R. Henderson, Opus Research, Opus International Consultants, New Zealand
Terjedelem: 77 oldal
This report details a framework for rationally arriving at economically justifiable operating speed reductions to compensate for the inability to achieve recommended levels of skid resistance on high-risk curves. The framework is based on vehicle speed-related procedures incorporated in the Transport Agency’s Economic evaluation manual. These procedures include travel time, vehicle operating costs, carbon dioxide emissions and crash severity. Relationships between the skid resistance level of the road surface and curve crash risk and expected service life of the road surface derived from previous New Zealand specific research are also employed. The framework was trialled on a 10 km section of state highway 58 with a 100 km/h speed limit. A decrease in operational speed of only 10 km/h was found to be sufficient to completely negate the increased curve crash risk that results when the skid resistance of the high crash risk curves is managed to a lower level of 0.4 ESC rather than the recommended investigatory level. The overall benefit of reducing the 100 km/h speed limit by 10 km/h amounted to an annual cost saving of about $1.5 million, with the reduction in speed change cycle costs making the largest contribution.
A közösségek felkészítése az önvezető járművekre
Szerző(k): D.C. Rouse, J. Henaghan, K. Coyner, L. Nisenson, J. Jordan, American Planning Association USA
Terjedelem: 44 oldal
This paper summarizes the findings of a symposium and research on the implications of autonomous vehicles for cities and regions. It is intended for planners and local government officials involved in land-use planning, urban design, and transportation. Readers will learn about the need to plan for the potential benefits and negative impacts of autonomous vehicles and what steps they can take now to prepare their communities.
Iowa állam közúti biztonsági értékelési útmutatójának fejlesztése
Szerző(k): Veneziano, K. Knapp, Iowa State University USA
Terjedelem: 56 oldal
A road safety audit or assessment (RSA) is a formal review of the safety performance and features of a site by a multidisciplinary team with no prior experience with the site. RSAs are an effective tool for improving roadway safety. Federal Highway Administration (FHWA) guidelines for RSAs have existed since 2006, and most states have adopted those guidelines with modification to meet local needs. This project reviewed current national and state RSA literature and surveyed a small sample of states on their RSA practices to define RSA guidelines and practice. That information, as well as the current approach to RSAs in Iowa, was used to develop a suggested RSA process for the future in the state. The literature review found that states generally follow the 2006 FHWA eight-step RSA process. The eight steps in the FHWA process include project identification, team selection, pre-meeting, field review, analysis and report preparation, presentation of findings, preparation of formal response, and incorporation of findings. Some variations in the process are in use by some states, but these are largely related to the expansion of specific steps. An in-depth review of RSA processes in four states (Nevada, Ohio, South Dakota, and Virginia) found that each state generally followed the FHWA guidelines. The RSA approach suggested for Iowa is based on a process that has evolved to meet the needs of those requesting the assessment. The eight steps suggested for Iowa RSAs include (1) Project Identification, (2) Team Development, (3) Background Data Compilation, (4) Pre-Assessment Meeting, (5) Field Review, (6) Memorandum Development, (7) Memorandum Delivery, and (8) Incorporation of Suggestions. Changes, updates, or revisions to the Iowa process can and should be incorporated as necessary in the future, as the need arises. Report appendices highlight data and sources, checklists of items for field reviews, a sample field note sheet, and a suggested memorandum template. This information is intended to support and guide an RSA team throughout the assessment process. The approach outlined in this document can be employed by any group that conducts an RSA in Iowa. This will result in consistency between RSAs, regardless of who conducts them.