Australian Road Research Board Research Articles

Field trials of unbound granular pavements treated with an insoluble dry powdered polymer

Unbound granular pavement materials deteriorate with traffic, time and water ingress. In-situ recycling of fatigued pavement layers can be cost-effective, provided that appropriate additives are chosen. The polymer additive used in this study is suitable for aggregates with clay-rich fines. It is an insoluble dry powdered polymer (DPP) and is a proprietary product. According to Australian Road Research Board’s certificate, DPP is a granular powder comprising a cationic polymer thermally bonded to fine ground limestone. Long-term field trials of two in-situ recycled road sections on semi-rural roads were established to support an ongoing laboratory investigation. The polymer was suitable for these trials due to poor site drainage and risk of flooding. Field data from the La Croix deflectograph indicated good performance of the treated sections compared to the adjacent control sections. At the first site, the average central deflection under wheel loading over five years of monitoring was 0.3 mm compared with 0.6 mm over the control section. The second site initially showed similar level of improvement (0.5 mm compared with 1.1 mm), but deterioration of the treated pavement became evident with average deflections increasing to 0.8 mm by spring of 2020. Central deflection information can be supported by deflection ratio data. Visual inspections of road conditions highlighted the need for caution with shrinkage of the material treated with DPP. Transverse shrinkage cracks between 1 and 2 mm wide were observed. Laboratory testing of one of the granular materials confirmed high levels of shrinkage.

Gravel Loss Prediction Model Using Beta Regression

Unpaved roads consist of considerable portions of the roadway network in many countries. These roads play crucial roles in the development of infrastructure systems, advancements of socio-economic activities and improvements of the agricultural and production sectors. Thereby, unpaved roads benefit the underdeveloped, rural, and remote neighborhoods, and act as lifelines for these geographically disadvantaged communities. Frequent and regular maintenance activities keep the roadway system operational at a desired level of service. Resurfacing is one of the major maintenance treatments for unpaved roads. A gravel loss prediction model (GLPM) can evaluate the impacts of varying magnitude of resurfacing treatments on the roadway performance. Thus, a GLPM can provide valuable insights for roadway maintenance budget scheduling and decision-making tasks. In this paper, the backgrounds, input requirements, and output results of three popular GLPMs were reviewed. These models were (i) Highway Development and Management Model 4 (HDM-4), (ii) South African Technical Recommendation for Highways Model 20 (TRH-20), and (iii) Australian Road Research Board (ARRB) Model. In addition, the practicality of roadway resurfacing frequency charts which were developed based on these models was also evaluated. This study determined that the existing GLPMs and the corresponding roadway resurfacing frequency charts were often unreliable and impractical. In this study, a beta regression (BR) analysis methodology was utilized to develop and calibrate a GLPM for Iowa. Because of its simplified yet effective nature, the BR model outperformed the popular GLPMs and offered a practical approach to quantify annual roadway gravel loss.

Evaluation of Back of Queue at Signalized Intersections in Erbil City Using Different Software

Aims: The aim of this study is to evaluate the queue length of isolated signalized intersections, which used HCS2010 and SIDRA Intersection 8 traffic software. Background: One of the important parameters to evaluate the performance of a traffic management system is queue length, especially in congested traffic situations. For the estimation of back of queue length, many traffic analyzing models are used based on Highway Capacity Manual (HCM2010). Objective: The values of queue length obtained from these two softwares are to be compared with observed queue length from the field. The study also aids in conducting a model of optimization for the back of queue length to decrease the value of storage length of vehicles following the GA procedure. Methods: In this study, four isolated signalized intersections were used in Erbil city, the capital of the Iraqi Kurdistan Region. The values of the measured back of queue lengths are compared with the values obtained from Highway Capacity Software HCS2010(HCS+T7F) and Signalized and Unsignalized Intersection Design and Research (SIDRA Intersection 8) Aid Australian Road Research Board (ARRB) software. Results and Discussion: The results of regression analysis showed that the SIDRA Intersection 8 Back of Queue model with adjusted R2 0.8465 have a stronger relationship with the field measured Back of the Queue for linear relationship compared to the HCS2010 back of queue model. Furthermore, the study tends to optimize the signalized intersections under study using HCS2010 and SIDRA Intersection 8 software based on the Genetic Algorithm (GA) to minimize the back of queue length. The percent of average reduction in HCS2010 and SIDRA Intersection 8 back of queue models are 36% and 29%, respectively. The main objective of optimizing the timing plan was to minimize the average storage queue length at signalized intersections that follow the Highway Capacity Manual (TRB 2010) procedure for queue length calculation. Moreover, 95th and 98th values of the percentiles were chosen to estimate the expectancy of upstream lane blockage and the expectancy of short lane overflow that was related to the back of the queue percentile. Conclusion: The improvement of vehicle storage for upstream lanes was conducted by the two software systems mentioned before. The results showed significant improvement in the performance of the intersections under study with a reduction in queue length.

Pavement Performance Testing of the Newly Constructed Port Reitz and Moi International Airport, Mombasa Access Road

The 6.4 km long Port Reitz/Moi International Access Road project constructed under the design and build procurement method with an inherent risk of poor quality. A post-construction pavement performance evaluation is thus critical to evaluate the extent to which poor quality occurred. The International Roughness Index was measured using the Hawkeye-2000 Digital Laser Profiler with Pavement Logging Video Camera mounted on a calibrated vehicle and data was analysed using the Hawkeye Processing Toolkit Version 5.0.45, while the road roughness Rating was based on the Australian Road Research Board. The video record was analysed in blocks of equal lengths of 100 m for observation and assessment of the surface defects. The level of defects observed graded together with the IRI measurements gave the Present serviceability Index. Pavement Serviceability Index (PSI) was computed in compliance with ASTM 6433. The falling weight deflectometer equipment meeting the requirement of ASTM D4694 - 09 and ASTM D4695 used to measure pavement deflections under known load simulated the behaviour of the as-built pavement under loading, thus giving the pavement strength and the expected pavement life span. The deflection measurements were conducted on all lanes at intervals of approximately 100 m. The raw deflections (rd) data were converted to normalised deflection (nd) to simulate a standard pressure of 707 KPa from a dual-wheel assembly of 10-ton (100-kN). Back calculation of deflection data done using Rosy Design Software determined the layer strength and residual life. The analysis indicates that the road has residual life ranging from 20-6 years compared to 20-year design life consistent with the assumptions by Ogunsanmi (2019) that Design and Build contracts have an inherent risk of poor quality. In addition to incorporation and monitoring of quality through the design, construction and maintenance stages of the project, identification, evaluation, management, and monitoring of the inherent project risks are recommended for Design and Built Contracts in road projects.

Use of the Safe System Assessment Framework as a Safety Key Performance Indicator

As part of the Northern and South-Eastern Suburban Roads Upgrade packages, Major Road Projects Victoria has sought to incorporate road safety metrics into the tender designs review process. The Australian Road Research Board adapted the Safe System Assessment Framework (Austroads 2016) to meet this need. Twelve road projects were assessed to provide baselines scores for the reference designs. The submitted tender designs will then be reassessed to provide an assessment of road safety in the designs. This work provided an extension in use of Safe System Assessment Framework as well as insight into current gaps in road safety design practice.

Roundabout performance analysis in the city of Medan

Medan city as one of the largest cities in Indonesia, currently has problems in the field of transport is quite worrying. Like the other cities in Indonesia, the growth of traffic volume can not be followed by improvement of existing infrastructure. It is characterized by frequent traffic jams, long queues and delays contained in the segment or intersection. One type of arrangement is a roundabout intersection. Roundabout intersection canalization is composed of a central circle surrounded by a one-way street. Roundabout can act as a controller, divider and guidance for the traffic system which rotates in the direction. This study aims to determine the performance of the roundabout on the road Ir. Haji Juanda, Medan. Analyses were performed to obtain the performance of these intersections. Analyses were performed by using a calculation method MKJI 1997 and the Australian Road Research Board (ARRB) manually. The performance measures analyzed in the form of the degree of saturation, delay and queue opportunities using the method MKJI 1997. whereas the ARRB method, the calculated performance of the roundabout is the degree of saturation and delay. Good infrastructure handling can create a reduction of delay, and congestion, so that it can reduce pollution and support a more green environment.

Optimization of traffic signal parameters based on distribution of link travel time

In order to make full use of digital data, such as data extracted from electronic police video systems, and optimize intersection signal parameters, the theoretical distribution of the vehicle’s road travel time must first be determined. The intersection signal cycle and the green splits were optimized simultaneously, and the system total travel time was selected as the optimization goal. The distribution of the vehicle’s link travel time is the combined results of the flow composition, road marking, the form of control, and the driver’s driving habits. The method proposed has 15% lower system total stop delay and fewer total stops than the method of TRRL (Transport and Road Research Laboratory) in England and the method of ARRB (Australian Road Research Board) in Australia. This method can save 0.5% total travel time and will be easier to understand and test, which establishes a causal relationship between optimal results and specific forms of road segment management, such as speed limits.

Intersection Signal Management Based on Multi-Objective Optimization and Decision

Aiming at solving the multi-objective signal timing optimization and decision making problem for isolated intersections, a multi-objective optimization and decision making integration method is proposed in this paper. Firstly, a multi-objective optimization signal management model is established. Then multi-objective optimization algorithm Hyper-volume Estimation Algorithm (HypE) is used to obtain the signal timing described as Pareto set, and an improved method for uncertain multi-attribute decision problem in which attribute weights are set as interval numbers is proposed to select the satisfactory solution from the Pareto set. Simulation results show that compared with entropy weight method and Technique for Order Preference by Similarity to an Ideal Solution (TOPSIS) method, the proposed method not only can balance the tradeoff between preference demand of decision-makers and objective evaluation information, but also improve comprehensive traffic efficiencies effectively. Moreover, in comparison with the classical Australian Road Research Board (ARRB) and Highway Capacity Manual (HCM) method, the proposed multi-objective optimization and decision making method proposed brings better control effects.

Long-Term Asphalt Trial: Results of Acoustic Tests After Three Years

In 2013, VicRoads initiated a long-term trial to investigate the acoustic performance of various asphalt pavements constructed as variations to the standard specification for Victorian roads (Simpson et al. in Proceedings of the 26th Australian Road Research Board (ARRB) conference, Sydney, Australia, 2014). Acoustic testing of these five variations included statistical pass-by tests, as well as close proximity (ISO/DIS 11819-2 in Acoustics—measurement of the influence of road surfaces on traffic noise—Part 2: the close-proximity method, International Standard Organization, Geneva, 2013) and on-board sound intensity measurements (AASHTO TP 76-12 in Standard method of test for measurement of tire/pavement noise using the on-board sound intensity (OBSI) method. American Association of State Highway and Transportation Officials, Washington, 2012). The data collected from the most recent trials are presented along with that previously gathered over the first 3 years of the trial. The best-performing section of pavement was found to be a wearing surface that was treated by diamond grinding, and that showed a consistent improvement in noise reduction of up to 3 dB(A) over the standard open-graded asphalt.

Ranking Binder Creep Performance Using the ARRB Elastometer

This paper discusses a laboratory study used to characterize bituminous binders based on their dynamic creep resistance. Laboratory testing using four different loading regimes on asphalt mixes with six different bituminous binders was undertaken. Creep cycles to 2% accumulated strain were used to define the creep resistance of the asphalt mixes with the various binders. Underlying viscosities of the bitumens were derived using the Australian Road Research Board (ARRB) Elastometer. Marshall stability was measured on the specimens that were prepared using gyratory compaction. Regression plots were prepared that link creep resistance, underlying viscosity, and Marshall stability. It was found that the ARRB Elastometer is able to measure underlying viscosity, which is a reasonable predictor of dynamic creep resistance. Marshall stability was also shown to be a good indicator of dynamic creep resistance. Therefore, simpler tests such as Marshall stability and Elastometer can be used to rank bituminous materials for asphalt mix design purposes in the laboratory.

Establishing Deterioration Models for Local Roads in Australia

Local government authorities across Australia have adopted a variety of pavement management systems (PMSs) for local roads to guide the development of pavement maintenance, rehabilitation programs, and the appropriate allocation of road funding. Many practitioners managing local roads (the majority of which are considered low volume) are becoming disenchanted with their PMS packages, since the forecast of pavement performance does not accurately reflect actual pavement condition. A reason for this deficiency is that the prediction models used in PMSs are based more on the performance of overseas pavements. Pavement deterioration models are a critical component in any PMS, and accurate models are essential in order to better manage roads at both strategic (network) and maintenance work (project) levels to gain greater value from the funding available. To develop appropriate deterioration models for local roads, it was considered necessary to establish a number of sample local road sites at which pavement performance could be monitored over time. The sites selected are representative of local road pavements and cover a range of road types, climatic conditions, traffic loading, soil types, construction techniques, and maintenance practices. The study being undertaken by ARRB Group (formerly the Australian Road Research Board) as a commercial research project to establish deterioration models for low-volume roads across Australia, both sealed and unsealed, is outlined. The methods used to gain national support for the study, methodology adopted, performance criteria established, collection methods used, and interim results are described.

Dust Control: Australasian Experiences with Various Chemical Additives

Road dust can degrade agricultural produce, affect health, reduce road safety, increase wear and tear on vehicles, and increase the rate of deterioration of the roadway. In October 1996, Australian Road Research Board Transport Research completed and published a study of various dust-control techniques. That report encompassed a worldwide literature search on various measures to control dust and a survey of municipal councils and other road authorities across Australia and New Zealand to ascertain what experiences people have had with the use of dust suppressants. The outcome of this study is to provide a guide to the reported effectiveness of particular dust suppressants under given circumstances and other methods to better control dust emissions.

Saturation Flow and Capacity of Shared Lanes: Comparative Evaluation of Estimation Methods

The operation of shared lanes, especially in the case of permitted phasing control, is still considered a complicated task and one for which many procedures and methods have been introduced. Dealt with here is the complexity when left- or right-turn movements or both are made during the unsaturated part of the opposing traffic flow. Three main methods used for estimating the shared lane's saturation flow rate and capacity values—that used in the 1985 Highway Capacity Manual (HCM) and the Australian Road Research Board (ARRB) and the Canadian methods—were analyzed and evaluated. The methodology for the comparative evaluation was based on two main approaches. In the first approach, example 1 of Chapter 9 of the HCM was used as a case study in which left through and left through right shared lanes exist in permitted phase control. In this case several computer runs were performed using the programs SIDRA and SINTRAL to estimate saturation flow and capacity values of the shared lanes opposed by different traffic volumes of the conflicting movements. Results of this approach showed that the 1985 HCM and ARRB methods are fairly close in estimating saturation flow and capacity, whereas the Canadian method gave considerably different results. Analysis showed that the sensitivity of the Canadian method to estimate saturation flow rates of the shared lane in cases of different levels of opposing traffic was an average of 10 times higher than the average of the two other methods, which were very close in their estimation of levels of opposing traffic volumes. In the second approach, field measurements of saturation flow rate values of shared lanes at different locations and operational conditions were compared with the values estimated by the three methods under the same conditions. Results, based on field observations, revealed that the Canadian method estimates of saturation flow were always lower than the measured values. At low saturation flow values, HCM estimates were slightly higher than the observed values; however, at higher saturation flow rate values. HCM estimates closely matched the observed ones. The ARRB method estimates were quite close to the observed saturation flow values under all of the different conditions considered in the field observation task.

Saturation Flow and Capacity of Shared Lanes: Comparative Evaluation of Estimation Methods

The operation of shared lanes, especially in the case of permitted phasing control, is still considered a complicated task and one for which many procedures and methods have been introduced. Dealt with here is the complexity when left- or right-turn movements or both are made during the unsaturated part of the opposing traffic flow. Three main methods used for estimating the shared lane's saturation flow rate and capacity values-that used in the 1985 Highway Capacity Manual (HCM) and the Australian Road Research Board (ARRB) and the Canadian methods-were analyzed and evaluated. The methodology for the comparative evaluation was based on two main approaches. In the first approach, example 1 of Chapter 9 of the HCM was used as a case study in which left through and left through right shared lanes exist in permitted phase control. In this case several computer runs were performed using the programs SIDRA and SINTRAL to estimate saturation flow and capacity values of the shared lanes opposed by different traf...

ASPHALT DURABILITY: FROM LABORATORY TEST TO FIELD IMPLEMENTATION

ABSTRACT Spray and chip seals are the most important form of road surfacings in Australia. The long term hardening of the asphalt binder (its durability) is of critical importance in determining their life. The Australian Road Research Board (ARRB) Durability Test measures the intrinsic resistance of an asphalt cement to oxidative hardening and has been used in specifications for many years. A model which allows calculation of the rate of asphalt hardening in a sprayed seal has already been presented. It is based on data from road trials monitored for up to 15 years. A second model now permits calculation of the viscosity level at which seal distress occurs in a particular climatic area. By using the combined models it is possible to predict surfacing life. The parameters required for the calculation are the average temperature at the site and the asphalt Durability Test result. Application of the models to sites; in the U.S. suggests that, if seal lives comparable to those in Australia are to be achieved...

Driver perception of a series of on-road treadle sensors : Pitcher, I.K.Australian Road Res, 1989, 19.2, 173–178, 1 ref.

As part of an Australian Road Research Board (ARRB) research project involving the derivation of a relationship between vehicle speed and distance travelled along a residential street, it was necessary to establish a suitable data collection method. The method chosen involved the measurement of vehicle speed at designated points using a series of on-road treadle sensors. In order to assess the visual impact of a series of treadle sensors on the behaviour of motorists driving along a residential street, a preliminary test was devised which sought to determine the impact of dummy detectors on maximum vehicle speeds. Language: en

Efficiency and drag in the power-based model of fuel consumption

The efficiency and drag parameters in the instantaneous fuel consumption model are explained by comparing the model with the original power-based model developed at Sydney University, and relating the two models to a conceptual model. Various efficiency factors internal to the vehicle system can be modelled as contributing to the efficiency parameter, or explicitly as power components. The single efficiency parameter in the original power model includes engine drag and all other internal inefficiency components of the vehicle system. On the other hand, the two efficiency parameters in the Australian Road Research Board (ARRB) model have been derived in such a way that they do not include the engine/internal drag in the steady-state driving mode. A fuel consumption model that uses a drag force component measured by coast-down (in neutral) should employ a nonconstant efficiency factor (i.e. a factor dependent on speed and acceleration rates). Otherwise, a satisfactory level of accuracy cannot be achieved, particularly if the prediction of fuel consumption during different modes of driving is required. If all power terms are modelled explicitly, then a basic (constant) engine efficiency parameter can be employed. The basic efficiency factors found from engine maps are of the order of 0.06 to 0.08, which are very close to the values obtained for the ARRB model. This confirms the accuracy of the calibration method used for the ARRB model.

The Australian road research board instantaneous model of fuel consumption

The instantaneous model is an extension of the power model proposed in Post et al. (1984) in which the fuel consumption rate is assumed to be a linear function of the tractive power. The ARRB model includes additional regression-based terms to account for reduced fuel efficiency when the vehicle is operated in a high power mode. It also uses fuel consumption data, taken from constant speed vehicle tests, to determine rolling and aerodynamic resistance coefficients

A LASER-BASED HIGHWAY-SPEED ROAD PROFILE MEASURING SYSTEM

A large proportion of road roughness measuring equipment used throughout the world today is based on transducers which sense the relative movement between the vehicle body and its rear axle. Although these systems are reliable, simple to use, and have the capacity for the measurements to be performed over a range of travel speeds, the resulting roughness statistic is influenced by the ride characteristics of the host vehicle. In most cases the data are of limited use in the detailed study of vehicle dynamics. Other problems are calibration of the roughness vehicle, comparison between similar and dissimilar systems, and stability of the measures over time. To circumvent these problems, road profile based reference systems are gaining popularity with a resulting increase in useful data for vehicle dynamicists. To meet this need, the Australian Road Research Board (ARRB) has developed a highway speed, road profile measuring system to collect profile data on Australian roads. This device and the signal processing are described in this paper and some results are presented.

A discussion on the paper on fuel consumption modeling by Post et al.

The aim of this discussion is to inform readers about further work on these models carried out at the Australian Road Research Board with funding from the national energy research development and demonstration council. As a result of this work, an extended power based model was developed, and other models of fuel consumption, including a new elemental model, were derived from it. These models will be briefly discussed and a critical review of the work of post et al in comparing different aggregate models will be presented in this discussion note.