Conference Proceedings (VTTI)

Permanent URI for this community

https://hdl.handle.net/10919/50415

Browse

Now showing 1 - 20 of 212

Improving Highway Safety Through Pavement Friction Management Programs
Smith, Kelly L.; Larson, Roger M.; Flintsch, Gerardo W.; Sherwood, Jim (2012)
In recent years, there has been a major increase in activities related to improving highway safety in the U.S. Much of the emphasis has been placed on driver behavior (e.g., addressing aggressive, distracted, and impaired driving and the neglected use of seat belts) and roadway design (e.g., geometrics, roadside, and traffic control features), and this has led to updated FHWA regulations and guidance regarding the Highway Safety Improvement Program and major research publications, such as the NCHRP 500-series reports (Guidance for Implementation of the AASHTO Strategic Highway Safety Plan) and the 2010 American Association of State Highway and Transportation Officials (AASHTO) Highway Safety Manual (first edition). A similar upswing in activities has taken place with regard to the safety of pavement surfaces. Following efforts in the mid-1990s to comprehensively examine pavement surface characteristics (PSCs) (e.g., texture, friction, noise, hydroplaning potential), FHWA has developed policy guidance for Surface Texture for Asphalt and Concrete (Technical Advisory T5040.36) (2005), AASHTO has published the Guide for Pavement Friction (2008), and FHWA has developed policy guidance on Pavement Friction Management (Technical Advisory T5040.38) (2010). Building off these and other PSC-related technical advancements, and recognizing the need to apply pavement friction management (PFM) concepts and technologies in the U.S., the FHWA has sponsored a major, multi-year study to develop and demonstrate PFM programs at four state highway agencies (SHAs) using guidance contained in the AASHTO Guide for Pavement Friction. In Phase 1 of the two-phase study, a review of past efforts of quantifying the relationship between friction/texture and crashes was done, along with a review of both U.S. and International pavement safety programs/practices. In addition, a detailed evaluation of currently available friction/texture measurement equipment was performed to identify those best suited for the PFM programs to be developed in Phase 2 of the study. This paper discusses the examination of past studies investigating the friction/texture– crash relationship and the review of pavement safety programs/practices. It presents the main conclusions of these two research activities, as they relate to the planned development of PFM programs in four states (yet to be identified).
Simulative Polishing In The Laboratory; Comparison With Traffic And Use To Investigate Aggregate Blending
Dunford, Alan; Viner, Helen; Roe, Peter; Caudwell, Louise (2012)
Two experiments with the Wehner-Schulze machine, which is designed to apply a controlled amount of polishing to and measure the friction of road surfacing products, are described and their results summarised. In the first experiment the polishing action of the machine is compared to the polishing action of traffic using UK roads. It is shown that there is a strong correlation between friction measured after polishing by traffic in a non-event location and friction measured after polishing in the machine. It is shown that polishing in the machine is more severe than that applied by free-rolling traffic on straight roads. In the second experiment, the machine is used to show that it may be possible to predict the long-term friction performance of asphalt prepared with a blend of coarse aggregates using a mass ratio formula.
Ride Quality Assessment Using Probe Vehicle Acceleration Measurements
Katicha, Samer W.; Flintsch, Gerardo W.; Valeri, Stephen M. (2012)
New vehicle technology is leading to efficient methods for assessing the condition of the national highway system. Utilizing simple sensors installed in vehicles, such as accelerometers, could provide a cost effective way to assess ride quality for pavement management. This paper builds on a pilot study that compared data gathered from accelerometers to the current state of the art practices for measuring ride quality. After promising results with preliminary acceleration data, robust data collection was performed on the Virginia Smart Road under various operational conditions and using two vehicles: a Volvo truck and a Ford Fusion using the DAS system developed by the Virginia Tech Transportation Institute. Profile measurements were also obtained for comparison using an inertial laser profiler. Tests were performed at 40, 50, and 65 mph (65, 80, and 105 km/h). A GPS device was used to accurately calculate vehicle position and speed. Repeatability of acceleration and profile measurements were calculated. Effect of vehicle type and testing speed on the acceleration profile was estimated. Results show that under controlled testing conditions, roadway roughness can be accurately estimated using probe vehicle acceleration data. This suggests that instrumented probe vehicles might be a viable and effective way of implementing a pavement condition assessment program in the near future.
A Methodology To Evaluate Pavement Noise Performances For Characterisation, Checking And Monitoring Purposes
Anfosso-Lèdèe, Fabienne; Leroux, C. (2012)
Over the past decade, road industry developed efficient low noise pavements, providing rolling noise reductions up to 8 dB(A) compared to traditional dense asphalt pavements. With such a progress, road authorities are willing to introduce noise requirements in the tenders for road surface renewal. This implies that a general framework is accepted by both parties, defining the noise performance and describing the procedures to characterise or check it on site. Consequently, the National Working Group for Road Surface Characteristics (GNCDS) was tasked to develop a methodology to evaluate pavement noise performances for characterisation, checking and monitoring purposes. The members of GNCDS belong to public road authorities or institutes and private road companies. In this way, the methodology to be developed should integrate the concerns and possibilities of all stakeholders. In particular, special attention was paid to the difficulties that road contractors often face to reproduce noise performances of a given pavement product from one work site to another, due to unavoidable variations in the properties of aggregates or binder, in the laying process or in local practices. The methodology proposed is based on the method developed within the “SILVIA” EU project, but introduces several adaptations and simplifications to improve the practicability. Noise performance is defined by an absolute pass-by noise level at a reference speed (90 km/h in France). Therefore, the noise characterisation of a pavement is performed by a SPB measurement. At least two different sections on different sites with less than 1.5 dB(A) difference in noise levels, are necessary to define an average noise performance of the pavement product. A CPX measurement is also performed in parallel, to be used as a reference for the checking procedure of other sections of the same type of pavement. The paper will present the methodology developed, the experimental tests performed to check its applicability. Then some successful examples of application of this methodology will be presented.
Miriam: An International Round Robin Test To Compare Rolling Resistance Measurement Methods
Bergiers, Anneleen; Goubert, Luc; Anfosso-Lèdèe, Fabienne; Ejsmont, Jerzy A.; Sandberg, Ulf; Zöller, Marek (2012)
The MIRIAM project (Models for rolling resistance in Road Infrastructure Asset Management Systems) was originally established by twelve partners from Europe and USA. It aims at developing methods for improved control of road transport carbon dioxide (CO2) emissions in order to obtain a sustainable and environmentally friendly road infrastructure. The first phase of the project, taking place in 2010-2011, included a round robin test (RRT) to compare different rolling resistance (RR) measurement equipment. The RRT was organized in June 2011 on a test track in Nantes, France. Three institutes participated with their RR trailers. RR measurements were carried out on various surfaces, such as epoxy resin, surface dressings, thin layers, porous cement concrete, porous and dense asphalt concrete. Measurements were carried out at 50 and 80 km/h to assess the influence of speed on RR. A few tyres were used to study the impact of the tyre. Many runs were undertaken on the same surface to gain knowledge about repeatability and reproducibility of the test method. Texture measurements with laser profilometer were performed on the same test sections to investigate the homogeneity of the pavements and to study the relation between texture and RR. In this paper some results, analyses and conclusions of this pilot study are presented.
Selection Of The Most Cost Effective Pavement Maintenance Treatment For Selected Airport Pavements In New Mexico
Rahman, M.; Tarefder, Rafiqul (2012)
Due to environmental conditions and air traffic, pavements deteriorate with age. Periodic maintenance is of utmost importance to keep them in safe operable condition. Limited studies have been reported on airport pavement maintenance strategies. Cost benefit study of various maintenance alternatives should be analyzed to make the best use of allocated budgets. New Mexico has about 50 general aviation airports with pavement condition varying from serious to good. Most of these airport pavements require immediate maintenance treatment. The current need is to determine the effectiveness of various pavement maintenance strategies for these airfields. In this study, the results of a number of crack treatments (crack sealing, patching) as well as surface treatments (slurry seal, overlay) are compared in terms of Pavement Condition Index (PCI) improvement and resulting service life enhancement. The objective of this study is to select the most cost effective treatment by performing life cycle cost analysis and to select the optimum time for its application. The analysis shows that crack sealing has greater benefit to cost ratio and lower life cycle cost than patching. Also, the critical PCI plays an important role in selecting a cost effective treatment as well as aiming a target level of service.
About The Rolling Resistance Trailer And Parameters Influencing Rolling Resistance
Bergiers, Anneleen; Goubert, Luc; Vuye, Cedric (2012)
The issue of global warming by an excessive amount of carbon dioxide (CO2) in the atmosphere is a hot topic and the consequences for man and environment become more and more clear. Road transportation plays a significant role in CO2 emission and unlike other sectors, its emission has even increased the last years. To stop this trend, different measures may be taken: e.g. tackling traffic congestion, lowering the consumption of the vehicles… Many other parameters influence CO2 emission by transportation: e.g. tyre, vehicle and road characteristics… In this paper the influence of the road surface is investigated with a “quarter-car” trailer, suitable to measure rolling resistance with a car tyre on different road surface types. Texture measurements with a laser profilometer are performed to examine the correlation between rolling resistance and texture. The impacts of different parameters are investigated: repeatability over short and long time, speed, wind, tyre inflation pressure, tyre load, tyre type … Some rough coast down measurements are performed to compare with the trailer method. By gaining more knowledge about this topic, more environmental friendly and sustainable road infrastructure may be developed and implemented. This is expected to be an important tool for policy makers in their fight against CO2 emission.
Determination Of Correlation Between Road Pavement Skid Resistance And Braking Deceleration
Kokot, Darko; Rijavec, Robert; Ambroz, Miha (2012)
There are many situations when road pavement surface skid resistance drops to unacceptable levels. Skid resistance is an essential pavement property for road safety, but drivers are not able to assess its degree by visual means, although in the end they must be able to stop their vehicles safely within the stopping sight distance. In our research normalized braking deceleration was related to SCRIMTEX SFC values and analyzed for different driving conditions (wet/dry), vehicle systems, skid resistance levels, measuring speeds and nominal initial vehicle speeds when full braking. A relation can be used to calculate the stopping sight distance and maximum safe speed in different road conditions. In the case of below-average vehicle systems, relations of this kind can be used to determine, within some degree of uncertainty, the limit SFC values at which some traffic operations and management activities should be performed (e.g. speed limits can be reviewed and new traffic signs erected to support road users in safer driving). Applying such limit values to the national regulations means that they can be directly interpreted from the traffic safety perspective.
Fusion Of High-Resolution Laser Profile And Lidar Measurements For Enhanced Condition Assessment
Wright, Dean; Dhillon, N.; Wright, Alex; Christie, Colin (2012)
Accurate data on pavement condition is essential for the maintenance and assessment of road assets. This is commonly obtained using downward-facing laser survey devices operated traffic-speed to provide detailed measurements of the pavement surface. Interest in the use of LIDAR technology to complement such surveys has increased with better accuracy and cost-effectiveness of commercially-available systems. The potential applications of LIDAR systems have been demonstrated by several groups. These mainly focus on its ability to measure assets other than the pavement, as LIDAR is generally not considered to have sufficient accuracy to measure the pavement shape itself. This work undertakes an initial investigation of how LIDAR could be used in pavement assessment by using LIDAR to combine high resolution measurements collected over multiple survey lanes into a single set of data. This commences with the generation of 3D point clouds from all the measurement systems, followed by alignment and combination. The final hybrid 3D data set describes the pavement surface at a level of detail typical of traffic speed condition surveys. Potential applications in the field of pavement surveying include the improved identification of locations likely to affect vehicle handling, and the detection of areas at risk from ponding.
New Methods For Network Level Automated Assessment Of Surface Condition In The UK
Wright, Alex; Dhillon, N.; McRobbie, Stuart; Christie, Colin (2012)
Automated traffic-speed surveys have been applied on the English Strategic Road Network since 2000, under the Traffic-speed Condition Surveys (TRACS) specification, which employ image and laser-based equipment to measure surface condition at traffic speed. The original requirements for TRACS surveys were based on research carried out by TRL for the Highways Agency. However, there have been significant advances in the technologies for the measurement of surface condition since 2000. The introduction of a new contract in 2012 has provided the opportunity enhance the requirements. This paper focuses on the developments undertaken in two areas – rutting and surface disintegration. Rutting is a key indicator of condition, but the laser-based transverse profile systems used to quantify rutting can be adversely affected by features such as road markings. An approach has been developed to use high resolution transverse profile in combination with surface intensity measurements to remove the influence of such features. Surface disintegration is becoming a major source of deterioration on the SRN. This has required the development of an improved assessment method, which utilizes multiple laser texture measurements to identify disintegration over the full survey width. The research has lead to the publication of a revised survey specification for TRACS.
Variation Of The Observed Surface Strains Caused By Uniform And Non-Uniform Contact Pressures Using A Finite Element Method
Casey, Dermot B.; Airey, Gordon D.; Grenfell, James R.; Collop, Andy C. (2012)
The current practice in pavement design is to use a circular uniformly distributed load as the input to ascertain the maximum strains in the pavement. This is not the reality; tyre-pavement contact pressure distributions are very complex. The distress on the surface of the pavement in the form of rutting and surface initiated cracking is very much dependent on these complex pressure distributions. This study investigates the effects that non-uniform contact pressure distributions have in comparison to the traditional circular loading on the initiation and rate of accumulation of this distress. The problem has been modelled using the CAPA-3D finite element software. The traditional circular load was modelled. The strains in a number of key locations were recorded and measured. Then the non-uniform loading was modelled using the same procedure. What was of particular interest was the difference in the peak surface strains and positions between the two different methods of loading. The non-uniform loading created significantly larger strains under the contact patch. The non-uniform loading also created significant shearing forces close to the surface and under the contact area. This leads to a greater propensity for the surface to develop rutting and also for cracking. The differences started to become less evident with distance from the loading area for the principal stresses. It is recommended that for the design of surface layers non-uniform contact pressures should be used.
Identifying Fine Aggregates Prone to Polishing in PCC Pavements
Fowler, David W.; Rached, Marc M. (2012)
Surface polishing in portland cement concrete (PCC) pavements leads to higher incidences of skid-related accidents on highways. This type of failure is often associated with the usage of softer fine aggregate such as limestone sands. To identify polish resistance aggregates, state agencies like TxDOT have adopted tests such as the acid insoluble residue test (AIR). Since calcium carbonate is soluble in acid, no carbonate sand passes the AIR test which has a minimum limit of 60% in Texas. This paper describes research that was done to evaluate the polish resistance of aggregates using a laboratory concrete performance test. Concrete slabs made with different fine aggregates were evaluated for skid using a circular track meter (CTM), a dynamic friction tester (DFT), and a three-wheel-polishing device (TWPD). To ensure that the values obtained at the laboratory related to field performance, test sections constructed with 100% limestone sand and blended sands were also evaluated. Results show that some of the aggregates that failed the AIR test performed as well as some of the siliceous fine aggregates that passed the AIR test. Other aggregate tests such as the micro-Deval have shown to relate more closely to the concrete performance tests performed under laboratory conditions.
Assessment Of Polishing Behaviour Of Sand Using The Test Device According To Wehner/Schulze
Hofko, Bernhard; Kirchmaier, Lukas; Blab, Ronald; Mader, Matthias (2012)
To ensure the safety of road users during driving maneuvers an adequate skid resistance level of the wearing courses is required. Skid resistance of dense road surface layers besides the texture profile also depends on the polishing resistance of both coarse and fine aggregates. In the European standards so far requirements concerning the polishing behaviour of mineral aggregates are given merely with regard to the PSV (Polished Stone Value), tested on stone chippings 8/11 mm. No specific specifications are set for the sand fraction 0/2 mm. This paper details a new Austrian evaluation background for the polishing resistance of sand using a Wehner/Schulze testing device of the latest design. It will be showed that the polishing resistance between coarse and fine aggregates differs, thus separate requirements for different particle sizes are necessary because only the combination of highly polishing resistant sand and gravel enables a sustainable skid resistance of road surface layers. Furthermore the reproducibility and the comparability of sand polishing values determined by an accuracy experiment will be presented. Within the accuracy experiment different parameters, which may affect the test result, were investigated. Based on the evaluation background and the results from the accuracy experiment requirements concerning the sand polishing resistance were set for highly stressed wearing courses in the Austrian standards. This new requirement for wearing courses will lead to a better durability in terms of skid resistance and therefore to reduced maintenance costs.
A Routine Monitoring Method Using Weighted Longitudinal Profile
Kamiya, Keizo; Kawamura, Akira; Glattki, Winfried; Ueckermann, Andreas (2012)
Weighted Longitudinal Profile (WLP) which is a new index for characterizing longitudinal evenness was introduced in SURF 2008. As a result of sensitivity analysis of the WLP method using longitudinal profile data from the Japanese motorways, each of road surface distress showed its own identical tendency in a relationship between ΔWLP and σWLP. Moreover, since data sites with larger ΔWLP of bridge joint tend to emerge upward in the relation between profile variation Δ and standard deviation of profile σ in octave bands #3 and #4, both octave bands are considered to give critical values to the original surface profile. Because a laser profiler and a mobile profiling system, named STAMPER showed a similar slope of regression between Δ and σ, STAMPER can be used as alternative of laser profiler. By driving a STAMPER-equipped rent-a-car for 5 days on Autobahn, it was observed that IRI is distributed quite similarly between Autobahn and NEXCO motorways. It was also found that octave bands #5 and #6 are prevailing when profile variation Δ is low, or road surface is less deteriorated. Finally if STAMPER can be used routinely and WLP is calculated for surface distress type, this will be an innovative monitoring method.
A Mobile Profilometer For Road Surface Monitoring By Use Of Accelerometers
Tomiyama, Kazuya; Kawamura, Akira; Nakajima, Shigenori; Ishida, Tateki; Jomoto, Masakazu (2012)
Surface roughness of a pavement has been recognized to be an important parameter for determining maintenance and rehabilitation needs for road networks. To predict roughness condition reliably, an objective and repeatable profilometer must be used. However, most road agencies, especially for local governments, frequently monitor and determine the pavement condition through visual inspections. This study introduces a new mobile profilometer for more effective data collection and real-time monitoring of the pavement roughness. It consists of two small accelerometers attached to a vehicle suspension system enabling directly measurement of surface profiles using the back calculation of measured acceleration of a vehicle. The measured profile data in the proposed profilometer can be immediately converted to a summary roughness index such as the IRI. The roughness information is simultaneously displayed on an onboard computer in real time. This study also presents profile measurement experiments to verify the accuracy of the new profilometer for roughness data collection and demonstrates its benefits to pavement monitoring of local roads through an application case study.
Determination Of Pavement Surface Cracks From Video-Images Using An Image Scale-Space Approach
Armenakis, C.; Ningyuan, Li (2012)
Assessment of pavement surface distress is an important component of the pavement management process. Pavement surface distresses characterize failures and distortions of the pavement surface structure. A large number of highway surface images have been collected through the application of a video image system. We present an automated approach that detects pavement surface cracks from a forward viewing video camera system. Initially the oblique imagery is transformed to a rectified one which supports quantitative measurements of the crack patterns. For the detection and extraction of pavement surface distress elements, we propose to use a scale-space image approach, where the image scale is defined based on the level of detail of the image structure to be detected. Finally, the detection of crack patterns is performed considering the image as a 3D intensity surface where the bright and dark lines are considered as ridges and valleys. The approach is based on determining the local directions of the image curvature along the curvilinear lines, and determining where along these directional profiles the second derivative of the line profile reaches its maximum absolute value.
Development Of A Pavement Condition Assessment Method For The Interstate Highway System
Simpson, Amy; Groeger, Jonathan; Rada, Gonzalo R.; Guerre, Joseph (2012)
As part of a project conducted by the United States Department of Transportation (US DOT) Federal Highway Administration (FHWA), methods are being developed to assess infrastructure condition and health with a focus on pavements on the Interstate Highway System. The project scope includes development of prototype tools to provide FHWA and State DOTs ready access to key information on pavement and bridge performance based on these methods for assessing condition and health. These tools are designed to allow a better and more complete view of infrastructure health nationally and form the foundation for a performance management system for the US highway system. In support of this goal, a pilot study was conducted on a three-state corridor to investigate and compare methods for assessing pavement condition and, subsequently, health. As part of the pilot, three sets of data were compiled, processed, and compared: National (Highway Performance Monitoring System), State (primarily State Pavement Management System data and supporting information), and field data collection using an automated multi-function vehicle. This paper explores the results on the approach for categorizing pavement condition as Good/Fair/Poor. A summary of the findings are presented along with recommendations for future activities necessary to develop a pavement condition performance indicator.
The Management Of Skid Resistance In Australia – A National, State Or Local Task?
Hillier, Paul (2012)
It is widely recognised that providing appropriate levels of skid resistance and surface texture across a road network can make a valuable contribution in securing positive road safety outcomes. Yet, the proactive management of skid resistance is often viewed within Australia as being within the domain and achievability of state road authorities only, despite knowledge and experience from other countries (e.g. United Kingdom and New Zealand) that a number of local road authorities (local councils) procure skid resistance testing and are actively using the data. This paper starts by introducing (and comparing) the highway network in Australia, before looking at current published guidance / good practice concerning the management of skid resistance. The many reasons for, and challenges to, the development and implementation of a skid resistance management strategy at national, state and local levels are then identified.
Use and Limitations of Crash Data in Determining the Priority For Treating Sites with Low Skid Resistance
Viner, Helen; Coyle, Fiona; Brittain, Stuart; Caudwell, Louise (2012)
In assessing the treatment of sites with low skid resistance, the relative priority of lengths marginally below skid resistance threshold where there have been a number of recent crashes must be balanced with that of lengths substantially below the threshold with no recent crash history. The judgment is complicated by the highway authority having a duty of care to maintain the road in a safe and serviceable condition, so it is not acceptable to let the skid resistance deteriorate indefinitely, even if there have been no crashes. Furthermore, the analysis lengths are generally short and the number of crashes is generally small, leading to a high degree of uncertainty in estimating the underlying risk. And finally, as there can be a large number of sites that require investigation within any particular jurisdiction, there is a need for a simple method otherwise the whole process of site investigation demands a disproportionate level of staff resource. This paper describes an accident risk model that has been created to provide a simple and consistent method for rating the priority of treatments at locations with low skid resistance and the dilemma for determining how to incorporate crash data within decisions on treatment priority.
On-Board Estimation of Water Depth Using Low-Cost Sensors
Prevost, Delphine; Cerezo, Veronique; Do, Minh-Tan; Chabanon, Christian (2012)
Last century has seen the emergence of many active safety systems, which have highly participated in reducing the number of car crashes. Nevertheless, those systems can be improved. In particular, information about the wetness of pavement surface could be of high importance to evaluate real tire/road friction. This paper deals with a new way to estimate local water depths under the tires as the car is running. A direct measurement of the amount of water droplets thrown from rotating tires of the vehicle is used. Tests are performed on test tracks with a real passenger car equipped to estimate spray and splash of water created by the front right tire of the car. Different water depths are obtained by flooding test tracks then measuring while they are drying. An indicator linked to the amount of water droplets is defined and studied under different conditions. Effects of traveling speed, road texture or tire tread pattern are assessed. The relationship between the indicator and actual water depth is verified by using non-contact optical water depth sensors as a reference. This new method of measurement via water droplets is a major breakthrough in automotive engineering since low-cost sensors can be used to estimate the water depth.

Browse

Browsing Conference Proceedings (VTTI) by Issue Date

Results Per Page

Sort Options