Nemzetközi szemle: Szeptember

Burkolati nedvességtartalom mérés és a burkolat élettartam kockázat kapcsolata

Pavement moisture measurement to indicate risk to pavement life
Szerző(k):
G. Arnold, P. Fon Sing, T. Saarenketo, T. Saarenpaa
Road Science, New-Zealand
Terjedelem: 160 oldal

High moisture within pavements accelerates pavement deterioration. Ensuring water is kept out of these pavement layers increases life and saves maintenance costs. A high-speed moisture survey technique employed overseas, utilising ground penetrating radar combined with video and laser LIDAR, was used on a range of roads in the lower North Island. A unique moisture damage index was developed for use in New Zealand to enable the identification of high moisture levels at three different depths (top; middle; bottom) in 2m increments along the road using results from the ground and air coupled radar. In the free viewer software the road cross section can also be displayed to determine the rut depth, ditch depths, cross fall and high lip, which aid in determining the most appropriate improvement in drainage. The New Zealand trial of the moisture detection equipment showed higher rutting in road sections with high moisture, while low moisture was detected in areas of nil or low rutting. Ten test pits measuring moisture at top, middle and bottom depths showed the moisture detection survey conducted seven months earlier was correct in the assessment of high and low moisture for 80% of the time.

 

Javaslat Texas állam útminőség értékelésére az útállapot javulás figyelembevételével

A Proposal for Revising TxDOT Ride Specification to Account for Ride Quality Improvement
Szerző(k):
J.A., Prozzi, P. Buddhavarapu, S. Kouchaki A. de Fortier Smit
The University of Texas at Austin, USA
Terjedelem: 80 oldal

The objectives of this project were to i) develop a rational and financially justifiable pay adjustment system that incorporates “new” versus “old” ride quality and ii) evaluate the existing techniques to measure ride quality using Surface Test Type B or inertial profilers on short projects. To achieve these objectives, the researchers conducted an extensive review of ride specifications from other states, focusing on common ride measuring devices and roughness indices, and payment adjustment systems. A survey of past studies was also conducted that focused on the relationship between pre- and post-construction roughness and pavement performance, evaluating the need for incorporating the improvement in ride quality into the pay adjustment system. A comprehensive database was developed integrating Site Manager, Design and Construction Information System (DCIS), and Pavement Management Information System (PMIS) databases. The ride quality data was extracted from a total of 565 asphalt projects constructed from 2001 to 2011. Statistical analyses were applied to establish a pay adjustment scheme based on the gain in pavement life due to the ride improvement relative to ride quality prior to the project construction. As a result, a performance-based pay adjustment system was proposed that incentivizes or penalizes pavement projects according to the combination of change in the ride quality and post-construction ride quality. In terms of roughness measurement on short projects, the research team administered a survey questionnaire with specific and direct questions and in-person interviews designed to obtain insight into the practical issues associated with operating inertial profilers on short projects. A field experiment was also carried out to investigate the feasibility of using inertial profilers to measure roughness on short projects. The results of the field experiment and the survey revealed that an inertial profiler operated by an experienced driver could be used to measure the roughness on short projects, provided that sufficient data is collected for stabilization and initialization of the algorithms before that target section.

 

Gyalogos és kerékpáros forgalmi adatgyűjtési módszerek és technológiák: 2. fázis

Methods and Technologies for Pedestrian and Bicycle Volume Data Collection: Phase 2
Szerző(k):
P. Ryus, A. Butsick, F.R. Proulx, R.J. Schneider, T. Hull
Kittelson & Associates, Inc., University of California, University of Wisconsin, USA
Terjedelem: 79 oldal

This report documents the research conducted by NCHRP Project 07‐19(02), Methods and Technologies for Pedestrian and Bicycle Volume Data Collection: Continuation. This continuation project tested and evaluated automated count technologies that capture pedestrian and bicycle volume data, focusing on technologies that came onto the market too late to be included in the Phase 1 research (NCHRP Project 07‐19). The report presents combined results for a range of technologies tested by both the Phase 1 research and the continuation research (Phase 2). The research evaluated automated non-motorized count technologies in different settings, including ranges of temperature, varying weather conditions, mixed traffic conditions, mixed travel directions, and facility types (e.g., roadways, multiuse paths), to determine their accuracy and reliability in different contexts. This report documents the research findings on the accuracy and consistency found for the different automated count technologies. It provides a complete account of the process used to select technologies for testing, identify test sites, and evaluate the effectiveness of the technologies. It is clear from the testing that careful site selection plays an important role in the ultimate accuracy of the collected count data. It is also critical for practitioners to calibrate the counters they install at specific sites to obtain the most accurate and reliable results.

 

Ejtősúlyos teherbírás mérési adatok felhasználása a mechanikai-tapasztalati pályaszerkezet tervezésben és elemzésben 2. rész: esettanulmány jelentések

Using Falling Weight Deflectometer Data with Mechanistic-Empirical Design and Analysis, Volume II: Case Study Reports
Szerző(k):
J.E. Bruinsma, J.M. Vandenbossche, K. Chatti, K.D. Smith
Applied Pavement Technology Inc. USA
Terjedelem: 192 oldal

The need to accurately characterize the structural condition of existing pavements has increased with the recent development, release, and ongoing implementation of the Mechanistic-Empirical Pavement Design Guide (MEPDG). A number of different material inputs are required in the procedure, and it is important to adequately characterize and define them. The analysis of deflection data collected by the falling weight deflectometer (FWD) provides a quick and reliable way to characterize the properties of the paving layers, as well as to assess the load carrying capacity of existing pavement structures. With the release of the new MEPDG, there is a pressing need to identify and evaluate the way that FWD testing is integrated into the new design procedure. Moreover, as highway agencies continue to implement the MEPDG, best practices guidance is needed on how to effectively test existing pavement structures and interpret the results as part of a mechanistic-empirical pavement evaluation and rehabilitation process. This document is part of a three-volume report investigating the use of the FWD as part of mechanistic-empirical pavement design and rehabilitation procedures. In this volume, six case studies—flexible pavement, flexible pavement on rubblized Portland cement concrete (PCC), rigid pavement on granular base, rigid pavement on stabilized base, rigid pavement on existing flexible pavement, and composite (hot-mix asphalt (HMA) over PCC pavement)—were used to evaluate how FWD deflection data are used in the rehabilitation portion of the MEPDG. The case studies used data from in-service pavements. Specifically, deflection data and backcalculation results were used to characterize the existing HMA, PCC, stabilized and unstabilized bases, and aggregate and subgrade properties in the MEPDG design program. Laboratory testing results were compared with FWD results, and the final designs were found to be relatively insensitive to the differences in characterization of existing layer inputs. This is volume II of a three-volume report. The other volumes in the series are FHWA-HRT-16-009, Volume I: Final Report, and FHWA-HRT-16-011, Volume III: Guidelines for Deflection Testing, Interpretation, and Analysis.

 

Magas súrlódású burkolat felületi kezelés közösségi értékelésének vizsgálata

Public Satisfaction Survey of High Friction Surface Treatment
Szerző(k):
Lance C. Gentry
Heartland Market Research LLC, USA
Terjedelem: 45 oldal

Missouri adults in Callaway County were surveyed to capture their satisfaction with a local high friction surface treatment on westbound US 54. This treatment was implemented in Project J5P3012. The results are weighted proportionally to the county’s distribution in terms of geographic, gender, and age distributions. Overall, local Missourians were very satisfied with the treatment and agreed that it made the road safer and easier to travel. Questions pertaining to the best ways to communicate with Missourians were also asked and evaluated.

 

Infrastruktúra-barát járművek Texas gazdasági versenyképességének támogatására

Infrastructure-Friendly Vehicles to Support Texas Economic Competitiveness
Szerző(k):
J. A. Prozzi, P. Buddhavarapu, S. Kouchaki, N. Jiang, K. Savage, J. Weissmann, A. Weissmann, C. M. Walton
The University of Texas at Austin, USA
Terjedelem: 195 oldal

The researchers reviewed and extended the work done under Project 0-6736, Rider 36 OS/OW Vehicle Fees Study, and other similar efforts currently underway in Texas and other states and at the federal and international level to evaluate the effects of single, tandem, and tridem configurations on bridges and pavements, and developed guidelines for more infrastructure-friendly vehicle configurations. In addition, the researchers developed a cost recovery structure that adequately funds repairs to roads used by overweight trucks.

 

Motorizált két- és háromkerekű járművek biztonsága: közúti biztonsági kézikönyv döntéshozóknak és gyakorló szakembereknek

Powered two- and three-wheeler safety: a road safety manual for decision-makers and practitioners
Szerző(k):
World Health Organization
Terjedelem: 108 oldal

Road traffic crashes kill 1.25 million people each year. Like all road traffic crashes, those involving powered two- and three-wheelers (PTWs) such as motorcycles and e-bikes are often predictable and preventable, and should not be accepted as inevitable. Key risk factors for motorcycle traffic injuries are non-use of helmets; vehicle speed; alcohol use; mixed traffic conditions; lack of protection from the vehicle itself during a crash; and lack of safe infrastructure for PTWs, such as poor road surfaces and roadside hazards. Reduction or elimination of the risks faced by PTW users is an important and achievable policy goal, and despite the existence of proven interventions to prevent PTW crashes, in many locations PTW safety does not attract the attention it merits. This manual provides information for use in developing and implementing comprehensive measures to improve PTW safety. It examines the extent of PTW related fatalities and injuries, and the importance of addressing the key risk factors for PTW crashes. The steps outlined for conducting a situational assessment aim to help prioritize interventions, prepare a related plan of action and help implement and evaluate PTW safety measures. While the focus of the manual is action at local or regional level, the strategies presented can be applied at the national level. It is hoped that the modular structure of this manual will enable it to be adapted to suit the needs and problems of individual countries. The manual is applicable worldwide but specifically targets decision-makers and practitioners in low- and middle income countries.

 

Kerékpárosok biztonsága körforgalmakban

Bicycle Safety at Roundabouts
Szerző(k):
P. Aumann, K. Pratt, A. Papamiltiades
Austroads Australia
Terjedelem: 180 oldal

This report investigates how the geometric design components of a roundabout may contribute to bicycle crashes. An Australian and New Zealand crash analysis found that most of the crashes occurred at urban local road roundabouts, in 50 km/h speed limit zones. The crashes predominantly occurred on the circulating lane near the entry for an approach road and were right-adjacent type crashes. The study included an in-depth investigation of 17 roundabouts across Queensland, New South Wales and Victoria. A geometric analysis identified that the entry geometry of the roundabouts investigated would permit relatively high entry speeds, in excess of the target speed of less than 30 km/h. This target speed was adopted for analysis purposes, however, further investigation to determine an appropriate speed to prevent or minimise fatal and serious injury outcomes for crashes involving motor vehicle and cyclists is needed. The motor vehicle speeds on the entry and circulating lanes were estimated using the ARNDT crash prediction model, however the model was developed on rural roads and so the application of this model to urban local roads requires verification. For the purposes of this investigation, the ARNDT model was used to assess geometric alignments to achieve lower approach speeds and it was found that a roundabout with a radial-type of alignment, used in countries in Europe, achieved approach and circulating speeds of less than 30 km/h. Sight distances were examined and it was found that the available sight distance to vehicles approaching from the right did not meet the design requirements. There is some research which indicates that restricting the sight distance on the approach to a roundabout reduces the approach speeds of vehicles, however, this requires further investigation to develop design criteria. The report recommends further investigation into motor vehicle/cyclist crash outcomes and the effect of restricting sight distance on the approaches to a roundabout, and the development of design guidance for urban local road roundabouts.

 

Meleg (Warm Mix) aszfalt technológiák hosszú távú helyszíni teljesítménye

Long-Term Field Performance of Warm Mix Asphalt Technologies
Szerző(k):
Washington State University, Pennsylvania State University, Louisiana Transportation Research Center, USA
Terjedelem: 127 oldal

An increased awareness of sustainability in the pavement industry has encouraged the use of warm mix asphalt (WMA) technologies. Compared with conventional hot mix asphalt (HMA) that requires a high production temperature, WMA has several benefits, such as saving fuel and energy, reducing greenhouse gas emissions, and improving the work environment. However, truly sustainable pavements should not compromise field performance. Therefore, evaluation of the long-term field performance of WMA has become critical for WMA users. NCHRP Project 9-49A focuses on the long-term field performance of several WMA technologies. The 28 WMA projects selected in this study, including 5 newly constructed projects (i.e., constructed during the course of the study) and 23 in-service projects, cover different service ages, traffic volumes, pavement structures, WMA technologies, and four climate zones across the United States. Each project has a HMA control pavement and one or more WMA pavements. The main objectives of this study include the following: Evaluate long-term field performance of WMA by comparing distresses (transverse cracking,
wheel-path longitudinal cracking, and rutting) between HMA and WMA pavements. Determine significant determinants for each type of distress by comparing the HMA and WMA field performance of various mixtures and asphalt engineering properties. Propose best practices regarding the use of WMA technologies.

Önvezető járművek és a közösségi politika

Automated Vehicles and Public Policy
Szerző(k):
P. Lewis, G. Rogers, S. Turner
Eno Center for Transportation USA
Terjedelem: 34 oldal

Automated vehicle (AV) technology has the potential to completely change how we travel, how we ship goods, and on a larger scale, how we think about mobility. While fully automated vehicles are not yet commercially available, the technology is developing rapidly and some robotic driving functions are already on public roads today. The governments are under pressure to craft regulations and make investments that encourage innovation while still enhancing safety and protecting the public interest. In 2016, the National Highway Traffic Safety Administration (NHTSA) developed its Federal Automated Vehicles Policy, the first step in creating a federal AV policy. Meanwhile, thirty-nine states and the District of Columbia have proposed or enacted a variety of AV policies, resulting in a troublesome patchwork of laws and regulations that are often inconsistent. As part of Eno’s Digital Cities program, Eno crafted a multifaceted set of recommendations that address the most pressing policy issues for AVs. If applied and executed properly, these recommendations will help guide this technology towards safe, efficient, and sustainable deployment.