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Part-fill and part-cut subgrade is widely distributed in mountainous highway engineering, and their resilient modulus and settlement exhibit significant transversal non-uniformity, which has an important effect on the performance of cement concrete pavement structure. A numerical model, focusing on a two-slab system on part-fill and part-cut subgrade, was developed by the finite element computer programme taking into account non-uniform settlement (a large range of partial contact) simultaneously with non-uniform modulus. Cement concrete pavement structure responses, including the load stress, vertical displacement and joint load transfer capacity were comprehensively investigated considering the two part-fill and part-cut subgrade characteristics. The results indicate that the non-uniform settlement has a higher impact on the concrete pavement structure than that of the non-uniform modulus in more cases. When the resilient modulus of the fill part is close to that of the cut part, the additional stress (relative stress increment) caused by the combination of the two factors is approximately the sum of the additional stress caused by the two factors individually. [ABSTRACT FROM AUTHOR]

The smoothness achieved in pavement construction, or as-built roughness, has great importance in road engineering. Traditionally, as-built roughness has been studied in the literature from an empirical approach, based on the statistical correlation between the roughness IRI observed before and after the execution of paving works. In the case of asphalt overlays, this article highlight interactions in the construction process that limit the predictive capacity of the traditional empirical approach; demonstrating, through the frequency response of the paver screed and the IRI model, that fitting a before-after IRI type regression is insufficient to explain the variability observed in as-built roughness. From the preliminary analysis carried out an original approach to as-built IRI prediction is proposed, based on the modelling of the asphalt paver and its levelling response to surface roughness during the paving process. Formulation of linear systems that constitute the model are presented for the case of a wheeled paver without using of automatic levelling. Longitudinal profile data from the Long-Term Pavement Performance SPS-5 experiment was used to calibrate the model, obtaining a mean error of 0.22 m/km for the predicted IRI. The results obtained demonstrate the potential of the proposed approach as a modelling alternative. [ABSTRACT FROM AUTHOR]

For the particular engineering-geological conditions and natural environment in permafrost regions, the highway has a high damage ratio during the operation. In warm and ice-rich permafrost regions, highway pavement and embankment have poor serviceability, which threatens driving the vehicle and safe operation. Traditional field surveys on highway damage cannot entirely, rapidly and precisely obtain the distress information along the whole road. In this paper, the Qinghai-Tibet Highway (QTH) pavement distress was investigated in 550-km-long permafrost regions based on the field surveys in 2014 and 2019 and the unmanned aerial vehicle (UAV) imagery. The type and damage ratio of distress were extracted by the remote sensing image classification method. The pavement roughness and embankment height were acquired by the spatial analysis of geographical information system. This paper provides a novel insight and efficient method for the distress investigation and exploration of distress formation in permafrost region, which can be applied in other similar engineering projects in the cold and inclement permafrost region. Furthermore, this paper also presents valuable and first-hand field data for evaluating highway serviceability and prevention of road damage during operation and maintenance stages. [ABSTRACT FROM AUTHOR]

To further improve the application quality of the waterborne epoxy resin (WER) in road engineering, a variety of WER and polyurethane-modified WER were prepared. The WER was treated by acid solution immersion, alkali solution immersion, salt solution immersion, oil immersion or artificial-accelerated aging. The mechanical properties of the WER before and after the treatment by various methods were tested. Based on the ideal point method of entropy weight, the influence degree of each treatment method on the mechanical properties of the WER was analysed, and the mechanical properties decay and residual mechanical properties of the WER were evaluated. The bonding durability of the WER was analysed. The results show that after the xenon lamp aging treatment, the mechanical properties of the WER decreased most significantly. The mechanical durability of the WER modified by polyurethane is improved to a certain extent, and the retention rates of their mechanical properties are >85%. After treatment by various corrosion or aging methods, the retention rates of mechanical properties of the PUE-E44 WER are >89.29%, showing an improved corrosion and aging resistance. The residual mechanical and bonding properties of the PUD-E51 WER are at a high level, and still show improved mechanical and bonding properties. [ABSTRACT FROM AUTHOR]

In cold regions, the mechanical performance of cement-stabilised macadam (CSM) deteriorates significantly due to freeze–thaw (F-T) actions. This paper attempts to investigate the F-T attenuation mechanism of mechanical performance of CSM from the perspective of the evolution of voids structure. To this end, multiple groups performance tests were conducted to study the effect of cement content, freezing temperature, and humidity conditions on the mechanical performance of CSM. Then the size distribution and evolution process of internal voids of CSM after F-T actions were investigated by computed tomography (CT) test. The results indicate that the resilient modulus (RM) and compressive strength (CS) of CSM decrease when F-T cycles increase until 15, and then stabilise gradually with a reduction of less than 5% in the last 5 cycles. It is presumbly attributed to the generation and melt of ice lenses in voids, distorting original matrix of particles. Additionally, increasing cement content can reduce the deterioration of mechanical performance, while increasing moisture content and decreasing freezing temperature promote the deterioration of mechanical performance. The F-T actions cause volume expansion of the larger voids (>100 mm3) before 5 cycles and then mainly result in more small voids (<1 mm3) during 5∼15 cycles. There is an apparent linear relationship between average voids ratio and RM and CS for CSM. The correlation coefficient R2 is higher than 0.92 and 0.73, respectively. [ABSTRACT FROM AUTHOR]

One of the most prevalent ailments of the road is crack. When it does, the standard of road engineering will be significantly lower and may even result in road collapse. Early detection of the cracks will result in significant maintenance cost savings if timely maintenance is performed. Although direct detection is highly challenging, the range of image cracks on the actual pavement is too large, the image quality is insufficient, the composition is complicated and the image range is too wide. Traditional manual detection methods have a number of drawbacks, including a lack of precision, a significant danger of detecting operation and a lengthy processing time. Therefore, in this research, we employed a novel technique based on image processing for the pavement detection method based on the features of pavement cracks. In order to avoid those difficulties Pre-processing (Median Filter), feature extraction (ResNet-50) and feature selection (Adaptive Salp Swarm Algorithm) techniques are also included in order to produce a clear image. With this proposed method, a variety of crack types including longitudinal, transverse, alligator and block can be identified. [ABSTRACT FROM AUTHOR]

In cold regions, the mechanical performance of cement-stabilised macadam (CSM) deteriorates significantly due to freeze–thaw (F-T) actions. This paper attempts to investigate the F-T attenuation mechanism of mechanical performance of CSM from the perspective of the evolution of voids structure. To this end, multiple groups performance tests were conducted to study the effect of cement content, freezing temperature, and humidity conditions on the mechanical performance of CSM. Then the size distribution and evolution process of internal voids of CSM after F-T actions were investigated by computed tomography (CT) test. The results indicate that the resilient modulus (RM) and compressive strength (CS) of CSM decrease when F-T cycles increase until 15, and then stabilise gradually with a reduction of less than 5% in the last 5 cycles. It is presumbly attributed to the generation and melt of ice lenses in voids, distorting original matrix of particles. Additionally, increasing cement content can reduce the deterioration of mechanical performance, while increasing moisture content and decreasing freezing temperature promote the deterioration of mechanical performance. The F-T actions cause volume expansion of the larger voids (>100 mm3) before 5 cycles and then mainly result in more small voids (<1 mm3) during 5∼15 cycles. There is an apparent linear relationship between average voids ratio and RM and CS for CSM. The correlation coefficient R2 is higher than 0.92 and 0.73, respectively. [ABSTRACT FROM AUTHOR]

One of the most prevalent ailments of the road is crack. When it does, the standard of road engineering will be significantly lower and may even result in road collapse. Early detection of the cracks will result in significant maintenance cost savings if timely maintenance is performed. Although direct detection is highly challenging, the range of image cracks on the actual pavement is too large, the image quality is insufficient, the composition is complicated and the image range is too wide. Traditional manual detection methods have a number of drawbacks, including a lack of precision, a significant danger of detecting operation and a lengthy processing time. Therefore, in this research, we employed a novel technique based on image processing for the pavement detection method based on the features of pavement cracks. In order to avoid those difficulties Pre-processing (Median Filter), feature extraction (ResNet-50) and feature selection (Adaptive Salp Swarm Algorithm) techniques are also included in order to produce a clear image. With this proposed method, a variety of crack types including longitudinal, transverse, alligator and block can be identified. [ABSTRACT FROM AUTHOR]

The geotechnical properties, chemical reaction mechanisms, and microstructure evolution of alkali-activated fly-ash-stabilised construction and demolition waste (C&D) and the main components recycled concrete aggregate (RCA) and clay brick (CB) were investigated in this study. The alkali activator was a composite solution of sodium hydroxide and water glass. XRD, FTIR, SEM, and UCS testing methods were used to analyse the properties and mechanisms of the alkali-activated fly-ash-stabilised C&D and main single-component RCA and CB. The test results demonstrate that using alkali-activated fly ash in stabilising C&D improves the UCS of the material significantly. When C&D is mixed with fly ash at a mass ratio of 60/40, its UCS reaches 37 MPa at 28 days, which is much higher than the strength requirement of cement-stabilised soil mixture and meets the strength requirements of inorganic binder stable materials for road base and sub-base layers. C-A-S-H and N-A-S-H (where N = Na2O, A = Al2O3, C = CaO, S = SiO2, and H = H2O) generated by the alkaline activation have several similarities with cement hydration products and also show high cementing ability. Alkali-activated fly ash improves the strength and stability of C&D as a roadbed filler and has prospective applications in road engineering. [ABSTRACT FROM AUTHOR]

The article explores the relationship between humans and other animals, technology, and engineering practices in a project testing Intelligent Transport Systems (ITS) in the arctic. Generally, roads are engineered to promote efficiency and predictability for transport. However, in the arctic northern region of Norway, animals sometimes challenge these virtues. Using Goffman's notion of frames and Callon's concept of overflow as theoretical starting points, the article explores how transport engineers develop intelligent transport infrastructure and envision ways of including animals and other non-humans in the engineers' framing of the road. The engineers first and foremost implement new technological artefacts, which allow them to survey the road in a manner which makes nature's overflows onto the road more manageable. However, these artefacts do not merely contain nature in the engineers' frame—the engineers also envision humans, in this case, motorists, to change their practices. As such, the engineers' attempts to contain animals in a particular frame entail using technology to assemble a new relationship between nature and culture. Taking nature into account when planning and developing infrastructure means reassembling a particular nature-culture relationship. Thus, the article points out that in order to engineer nature, it is also necessary to engineer culture. [ABSTRACT FROM AUTHOR]

As one of the main components of shotcrete, accelerator is widely used in housing construction, tunnel engineering and road emergency repair. In this paper, hydrofluoric acid, aluminum sulfate and aluminum hydroxide were used as main raw materials to prepare alkali free accelerator by liquid phase self reaction method. The influence of the amount of hydrofluoric acid, aluminum sulfate and aluminum hydroxide on the coagulation performance and stability of alkali free accelerator was mainly investigated. The test results are as follows: within the experimental range, the influence of aluminum sulfate on the coagulation performance of alkali free accelerator is greater than that of hydrofluoric acid. When the amount of 40% hydrofluoric acid is 100 g ∼ 160g, the amount of aluminum hydroxide is 50 g ∼ 80g, and the amount of aluminum sulfate is 320 g ∼ 400g, the alkali free accelerator products with main indexes of initial setting time ≤ 3 min and final setting time ≤ 6 min can be prepared, which meet the requirements of GB/T 35159-2017"Accelerator for shotcrete". The unit price of the optimized product is ¥1488 which is compared with the main products on the market, This product has good competitiveness. [ABSTRACT FROM AUTHOR]

Road safety audit (RSA) is a method used to proactively identify safety risks in road projects from planning, design, and construction stages. The effectiveness of the implementation of RSAs varies across the globe. This paper provides an understanding of road safety auditor's opinions and attitudes by using data collected from an online questionnaire filled by 408 road safety experts with varying demographic and technical backgrounds. Results demonstrated that majority of respondents agreed that RSA is an effective tool to improve road safety. Compared to high-income countries, respondents from low- and middle-income countries had less knowledge about RSA and less access to RSA guidelines. The results also indicate that many road safety auditors have a misunderstanding of the independence requirement for conducting RSA. The results of this paper can be used to inform and develop improved guidance to improve RSA generally and promote RSA as an effective road safety engineering tool. [ABSTRACT FROM AUTHOR]

The compaction behavior of solidified dredged fine sediments is an important parameter for recycling dredged fine sediments in road engineering. However, the Proctor compaction test is time-consuming, which could cause project delays. Thus, this study is aiming to develop simple models in order to correlate the compaction performance (Maximum Dry Density (MDD) and Optimum Moisture Content (OMC)) of solidified dredged fine sediments with the basic physical parameters of raw sediments and the types and quantities of binder. To create the models, a database of 94 measurements was established firstly from different literature studies. Then, a statistical approach was used to evaluate the effects of input parameters on the compaction parameters of solidified dredged sediments. In the third stage, four models were proposed as the optimum models to predict the MDD and the OMC of solidified dredged fine sediments. Further, the variance analysis (ANOVA test) and residual analysis proved that all the chosen four models meet the statistical requirements. In the end, the proposed four models were further validated using new experimental data, indicating that the proposed four models could be used to reasonably predict the compaction parameters of solidified dredged sediments with acceptable accuracy. [ABSTRACT FROM AUTHOR]

The increasing amount of waste vehicle tyres has already proved to be hard to dispose of properly and lead to environmental problems, such as soil contamination and toxic blazes. This study aimed to use recycled tyre rubber material (crumb rubber - CR) and combine it with well-known polymers in road engineering, such as styrene–butadiene-styrene (SBS) and/or a combination of SBS and ethylene-vinyl acetate (EVA) to develop hybrid recycled polymer modified bitumen (PMB). Most of the times, CR is only added to neat bitumen at high contents to enhance its properties despite some drawbacks. Physical, chemical, thermal and rheological tests were conducted to evaluate the overall performance of the blends with and without the addition of stabilising agents. CR has shown to increase the viscosity of the bitumen. The addition of EVA into CR/SBS blends has simultaneously improved the rheological properties specifically at intermediate and high temperatures. To conclude, the utilisation of small percentages of recycled tyres in PMBs and hybrid PMBs did not negatively affect the satisfactory performance of SBS-modified bitumen. This consequently encourages greater usage of CR which also mitigates the waste disposal problem at landfills. [ABSTRACT FROM AUTHOR]

The road layer modulus backcalculation based on the road deflection basin obtained by the Falling Weight Deflectometer is a key issue in road engineering. Traditional Falling Weight Deflectometer backcalculation method based on Artificial Neural Network has the disadvantages of poor generalisation ability and low convergence accuracy in terms of the dynamic modulus. In this paper, a hybrid neural network structure, combined with Residual Neural Network, Recurrent Neural Network and Wide & Deep (Abbreviated as ResRNN–W&D) structure, was proposed for Falling Weight Deflectometer deflection basin backcalculation. A case study using the United States Long-Term Pavement Performance database verified that the ResRNN–W&D structure can train Falling Weight Deflectometer data on multiple roads together and achieve fast and high-precision convergence, thereby greatly improving the availability of the multi-source heterogeneous data. Moreover, two transfer learning methods for the ResRNN–W&D structure were proposed to improve the divergence issue. It was found that the ResRNN–W&D structure has stronger generalisation ability than traditional Artificial Neural Network. [ABSTRACT FROM AUTHOR]

The lack of sufficient, accurate and time series dataset on road pavement surface condition in most developing countries over time has posed a serious challenge to highway engineers in terms of developing reliable pavement management system. This study examined the trend of flexible road pavement behaviour and surface condition classification from a historic dataset using intelligent algorithms such as; Random Forest (RF), Decision Tree (DT) and Naïve Bayes (NB) theory implemented in the Waikato Environment for Knowledge Analysis (WEKA) software. Some randomly selected highway links were considered for the investigation. The surface condition attributes considered included the percentage of fatigue cracks, average rut depth and drainage condition in a relatively comprehensive database obtained from the Federal Ministry of Power, Works and Housing Nigeria. Results of the analysis revealed the performance trend and classification of road pavement surface conditions based on surface distresses. The analysis indicated that, the RF and DT algorithms yielded accurate classification against the NB algorithm which could not handle instances of missing data efficiently, hence incurred classification errors. The use of experience-based models that could handle challenges of missing data in a dataset was recommended for the development of road pavement management system using such database. [ABSTRACT FROM AUTHOR]

In this article, the mechanical properties and material characterisation of graphite tailings concrete, in which graphite tailings are replaced as sand were investigated. The results showed that the concentration of graphite tailings has influence on the comprehensive performance of concrete. Simultaneously, the graphite tailings have an important improvement on reducing the mesostructure distribution and micro-crack density of cement-based materials. However, high content of graphite tailings can result in the growth on defects and significantly reduces strength properties. How to solve the adverse effect of high content of graphite tailings on reduced mechanical strength of concrete or taking full advantage of this material property and characteristics of graphite tailings is an urgent problem to be solved in the future research for practical engineering applications such as road subgrades, coastal breakwaters and so on. [ABSTRACT FROM AUTHOR]

Road safety is a major public health concern in our society. Effective road design and accurate safety analyses must be a component of programs focused on reducing and eliminating roadway injuries and deaths. Various methodologies exist to determine the expected number of crashes on rural two-lane rural roads. This research compares different procedures which allow for the estimation of the number of crashes on homogeneous road segments. In this effort, a total of 27 two-lane rural road sections located in North Carolina were considered, resulting in 59 homogeneous road segments composed of 350 horizontal curves and 375 tangents along 150 km of road. Four methods were applied to the selected roadways: the Highway Safety Manual predictive method, two jurisdiction-specific Safety Performance Functions (SPFs), and a SPF which includes a consistency parameter. This research found that the use of SPFs which incorporate a consistency parameter allows highway engineers to consider human factor impacts on road safety assessment. The use of a consistency parameter can also simplify the crash estimation process. Analysis methods which only included local geometric variables provided unreliable results due to the calibration of only the specific road elements instead of their relationship with other road elements along homogeneous road segments. [ABSTRACT FROM AUTHOR]

This study investigates the resilient modulus of vertical vibration compacted cement-stabilized macadam (CSM). The reliability of the vertical vibration compaction method (VVCM) for CSM was verified. Then the influences of four factors on the resilient modulus were studied and a resilient modulus prediction equation was proposed. Subsequently, the influences of aggregate type, cement dosage, and gradation on the initial and ultimate resilient moduli were studied. Results show that compared to the quasi-static-compaction method, the VVCM has a smaller influence on the optimum water content and aggregate gradation, and VVCM specimens have a higher correlation with the on-site cores. The increase of cement dosages and curing times can improve the resilient modulus and the proposed prediction equation can accurately predict the resilient modulus growth of the CSM. When the cement dosage and aggregate gradation are identical, the initial and ultimate resilient moduli of the cement-stabilized limestone are the largest, followed by the cement-stabilized granite and sandstone. The initial and ultimate resilient moduli of the CSM increase linearly as the cement dosage increases. Moreover, the skeleton-dense gradation helps to improve the initial and ultimate resilient moduli of the CSM. This study provides guidance for the design and construction of a CSM base. [ABSTRACT FROM AUTHOR]

The preparation of nano-modified concrete and its application in road pavement materials have broad application prospects for improving the wear resistance of road surfaces and reducing engineering costs. This article mainly studies the cost-effectiveness of nano-materials applied in road pavement engineering. This article uses ABC classification method to analyze the project cost. First, it analyzes the impact of each factor of the project cost on the project cost, finds the corresponding A, B, and C factors, so as to focus on the management of the A project cost factors. Then analyze the A-type cost factors of the A-type cost factors, find the A-type influencing factors of the A-type cost factors, and take reasonable measures for corresponding management and control, so as to ensure the effective control of the project cost. The research results show that the occupancy cost of asphalt concrete, concrete C30 and other materials is 82.784%, which is a class A material; the cumulative occupancy cost of materials such as steel bars and backfill gravel is 89.170%, 91.179%, which is a class B material. Type A materials are the main cost-controlling materials, which are directly related to the success or failure of the total cost control of materials. Type B material is a secondary cost factor of material cost, and relatively important control management should also be carried out. The experimental results of this article show that the combination of nanomaterial technology and cost control of road paving engineering construction projects can not only save the cost of road paving engineering construction, but also reduce many unnecessary wastes, and further strengthen the cost control of road paving engineering construction projects. The management level reduces the construction cost of road engineering. [ABSTRACT FROM AUTHOR]

Reducing road traffic accidents (RTA) and their socioeconomic costs is an increasingly important priority in many countries. In recent years, many authors have proposed various approaches to analyse historical RTA data using Geographic Information System (GIS) tools, so that locations with high instances or risk of RTA – i.e., RTA hotspots or blackspots – could be identified and ranked. This could then enable limited road engineering resources to be prioritised for remediating more critical RTA hotspots and therefore reducing RTA rates. This paper presents the development of a new validation method to evaluate the application of four different hotspot analysis methods in ESRI ArcGIS 10.2 to identify and rank RTA hotspots using historical RTA data on a section of a road in Brunei Darussalam as a case study. A road safety audit was undertaken for six locations along the study road section to identify the risk levels at these locations. These risk levels were then compared with risk levels at the same six locations computed by four hotspot analysis methods: Network KDE by SANET, KDE+, Getis-Ord Gi*, and a recently proposed risk-based method – STAA – that accounts for RTA frequency, severity and socioeconomic costs. It was found that SANET-KDE overestimated the risk levels of road sections that are free of RTA. The results from KDE + showed the most deviations compared to the identified risk levels by the road safety audit. Getis-Ord Gi* was not able to identify RTA hotspots along the study road section of Jalan Tutong. However, the STAA method provided the most consistent results in comparison with the identified risk levels by the road safety audit. STAA, by having a better validity compared to other methods, provides a promising way to prioritise RTA hotspots for remediation, and thus reducing the associated socioeconomic costs. In addition, these findings demonstrated that the novel method of validation via risk levels determined by road safety audit was able to provide an independent measure of the validity of the hotspot analysis (HSA) methods. [ABSTRACT FROM AUTHOR]

Nano bentonite is a new kind of soil modification material, which can effectively improve the physical and mechanical properties of clay. The development of new soil modification technology has been a research hotspot in geological engineering, geotechnical engineering and road engineering. The purpose of this study is to test and analyze the strength and consolidation characteristics of clay modified by nano bentonite, and to explore the new clay materials applied in modern geological engineering. In this study, an installation test was carried out on the preparation of nano bentonite, and the compressive condition of the bentonite was observed. After that, the viscosity strength of nano bentonite was compared with that of undisturbed soil by the control variable method, and the nano bentonite was divided into experimental group and control group. The viscosity strength and consolidation characteristics of nano bentonite were observed and analyzed by changing temperature, nano bentonite content, pressure and pore ratio. The results show that the consolidation coefficient of the sample without adding nano bentonite is 8.7 × 10–3 cm2/s, which is 6.6 × 10–3 cm2/s lower than that of 2% nano bentonite. It shows that the consolidation coefficient decreases with the increase of consolidation pressure and the decrease of void ratio. The nano bentonite modified clay is also more stable in road or building construction. The method of this study has brought a certain value for the research of nano materials in soil materials. [ABSTRACT FROM AUTHOR]

A conceptual non-linear, systems-based R&D management model for the road and transport sector was developed to address the associated complexities of transport and road research. It takes account of all the elements of the innovation value chain as well as stakeholders. It stimulates systems-thinking in the R&D management process and allows for a non-linear approach to the process with a number of process pathways, both 'backward' (back casting) and 'forward' thinking, thus facilitating eventual impact and uptake. It includes an impact assessment 'sensor' that influences the process of R&D management. The model was used to augment key performance indicators in an existing transport and road research programme. It was shown that a systems-based approach can improve the impact assessment indicators of an R&D programme in a community access roads and transport research programme. [ABSTRACT FROM AUTHOR]

Rutting has been one of the primary concerns for highway engineers in China. Granulated polymer anti-rutting additive may be an effective way to solve this problem. However, it is difficult to find previous research on the application of granulated polymer as an anti-rutting additive in different types of asphalt mixtures. This research aims to investigate the influences of the anti-rutting additive contents on road performances based on different types of asphalt mixtures, and also explores potential reasons for road performance improvement. Three types of asphalt mixtures: dense-graded asphalt concrete (DG-AC), dense-graded Superpave (DG-Superpave)，semi-open-graded asphalt macadam (SOG-AM), were included. Road performances, including high-temperature performance, low-temperature performance and moisture susceptibility, were studied at three anti-rutting additive percentages: 0.2, 0.3 and 0.4% weight of the asphalt mixture. The mixtures without the anti-rutting additive were regarded as control groups. In order to better analyse the road performance improvements, the properties of modified asphalt with 0.4% anti-rutting additive were studied, as well as the anti-rutting additive physical form in the asphalt mixture. It was found that the anti-rutting additive improved mixture's high-temperature performance significantly while its effects on low-temperature performance were not so. It reduced low-temperature tensile strain within 12.9% range. Moisture susceptibility was improved greatly after adding 0.2% anti-rutting additive as compared to the corresponding control groups. By increasing the additive contents to 0.3 and 0.4%, the moisture susceptibility had no significant difference compared with that of the 0.2% additive content group. Road performance improvements may relate to the combined action of reinforcement and gap filling by the elongated anti-rutting additive, as well as asphalt modification within short time. When the additive content is no more than 0.3%, the materials costs of the additive-modified asphalt mixtures are less than that of SBS-modified asphalt mixtures. [ABSTRACT FROM AUTHOR]

Evaluation indices were proposed and rated based on statistical analysis of collapse by an improved backward cloud algorithm considering internal and trigger factors. The evaluation index weight was calculated by a G1 method. A hazard evaluation of a highway collapse in China was established on the basis of a spatial analysis function of ArcGIS 10.2 and a factor superposition method. A hazard zoning of highway collapse in China was also performed based on the hazard degree. Results show that a comprehensive hazard index of highway collapse hazard in China based on the evaluation index above ranges from 1.0 to 9.0; and the distribution law of the collapse along a highway coincides with the actual distribution of highway collapse hazard. The most dangerous zones are the mountainous area of Southeast Taiwan, the mountainous area of Southeast Fujian–Zhejiang, south of Hainan, Sichuan–Yunnan mountainous area, Tianshan Mountains and Kunlun Mountains. The results can provide a reference for highway collapse prevention and mitigation work. Abbreviations: AHP: Analytic Hierarchy Process; GIS: Geographic Information System [ABSTRACT FROM AUTHOR]

Nine asphalt concrete overlays were prepared using three different mix designs: Type C, 12.5 mm Superpave, and Coarse Matrix High Binder Hot-Mix (CMHB-C) mixtures and three different coarse aggregate: siliceous gravel, quartzite and sandstone. Pavement overlays were placed on field sections constructed along IH-20 in Harrison County, Texas. Field sections included each of the nine different surface mixture types. The base course was the same for all surface mixtures and was designed with 90% limestone and 10% local field sand. For all mixtures including the base course, PG 76-22 binder was used. Three pavement condition surveys were conducted on the outside lanes of eastbound and westbound field sections; immediately after, after two years, and after three years of the construction of asphalt concrete pavement system. IRI values were estimated from the left and right wheel paths. Each data-set was analysed separately to compare the pavement smoothness of different asphalt concrete overlays. Section 3 (Superpave quartzite mix) in the westbound lanes and Section 4 (CMHB-C gravel mix) in the eastbound lanes showed the best ride qualities. A paired t-test was conducted for each section in order to assess changes in IRI values with time under real traffic conditions. Test results and statistical analyses indicated that except for the IH-20 westbound left lanes of field Section 3 (i.e. Superpave quartz mix) the IRI values of the asphalt concrete overlays were time stable over the research period of three years. [ABSTRACT FROM AUTHOR]

In order to investigate the enhancing effect of basalt fiber (BF) on toughness of asphalt, BF modified asphalt and mixture were prepared. Strip tensile test was performed to study the anti-cracking ability of BF modified asphalt. The effect of BF on toughness of asphalt mixture was investigated using MTS system. SEM was conducted to explore the enhancing mechanism of BF. The results showed that the ultimate tensile stress of BF modified asphalt peaked when fiber content reached 0.4% by weight of asphalt mixture. Composite materialization and self-healing force of BF led to the enhancing effect on toughness capacity of asphalt. [ABSTRACT FROM AUTHOR]

It is well known that pavement distress negatively affects the drivers and passengers of vehicles. Many studies report that foremost among these negative effects is the vibrations that form within the vehicle. Ride comfort depends on the human response to vibration and vehicle response to the road. The goal of this study was to investigate the effect of pavement condition index on ride comfort and to determine the threshold comfort limits for passenger cars on urban asphalt concrete pavements. The pavement condition index (PCI) was determined for pavement sections subject to different surface distress using the PAVER system. Ride (driving) speeds of 20, 30, 40 and 50 km/h were assessed on the same pavement sections to measure vibrational effects inside the vehicle and on the passenger seat. These measurements were then evaluated using the ISO 2631-1 standard in order to determine the a wz values. Using the logistic regression technique, predictive model that took into account linguistic concepts for estimating ride comfort levels based on PCI values was developed. With the aid of this mathematical model, comfort threshold values were determined for each driving speed within an interval of 0-100 PCI. The study results indicated that increasing driving speed was generally associated with higher PCI comfort thresholds. [ABSTRACT FROM AUTHOR]

Bridge weigh-in-motion (BWIM) is a technology that uses the bridge as a weighing platform to estimate vehicle weights. Previous research has shown that ignoring the transverse position (TP) of vehicles may lead to significant identification errors of vehicle weight for BWIM systems. However, the traditional method to identify the vehicle’s exact TP requires using axle detectors on the road surface. Aiming at achieving the nothing-on-road (NOR) BWIM, this paper proposes a novel NOR BWIM algorithm that is able to identify the vehicle’s TP and axle weights using only the weighing sensors. Numerical simulations are conducted using three-dimensional vehicle and bridge models and the proposed algorithm was used to identify the vehicle’s TP and axle weights. The results show that the proposed algorithm can successfully identify the vehicle’s TP and that the identification accuracy of axle weights and gross vehicle weight is significantly improved after considering the vehicle’s TP. The effects of the road surface condition, the vehicle speed, the vehicle width, and different measurement stations on the identification accuracy are investigated. The proposed algorithm is then verified by a field study and the results indicate that the proposed algorithm can achieve acceptable identification accuracy in practice. [ABSTRACT FROM AUTHOR]

Road traffic safety is emerging as an area of increased attention and concern in many countries including India. Safety evaluation by conflict study using surrogate measures is a proactive method which does not require any accident data. Conflict study may be carried out using post encroachment time (PET) as a surrogate measure, where critical conflicts are determined based on certain threshold value of PET. Identifying critical conflicts using a threshold value of PET is good and correct for highways and major roads where traffic follows posted speed, but on highways with mixed traffic for varied speeds this is not correct. It can be seen that conflicts with PET less than the threshold value may not be critical if the speed of conflicting vehicle is less. Similarly, conflicts with PET more than threshold value may also be critical if the speed of conflicting vehicle is high. The speed of conflicting vehicle is also important in evaluating severity of conflict. Hence, the use of PET alone for conflict study is not correct for evaluating safety of intersections on highways where traffic follows varied speeds. Therefore, in the present study, safety evaluation of an unsignalized intersection is carried out using two surrogate measures, PET and the speed of corresponding conflicting through vehicle. A term critical speed is proposed to identify critical conflicts. Critical speed for a particular PET value is determined using stopping/braking distance concept. Results show that there are significant percent of conflicts which are critical at the intersection. This shows that drivers of right-turning vehicles do take risks in accepting small gaps in through traffic at the intersection, which is dangerous. As crossing maneuver depends on length and speed of turning vehicle, the effect of type of turning vehicle has also been studied. Results show that right-turning light motor vehicles are at higher risk compared to two wheelers and heavy vehicles at the intersection. Safety evaluation of such unsignalized intersections may be carried out using this concept. [ABSTRACT FROM AUTHOR]

Deaths, injuries and disabilities resulting from road traffic injuries (RTIs) are a public health major concern. This study aims to calculate the burden of RTIs in Kermanshah Province in Iran. In this study to determine the years of life lost (YLL) related to RTIs, the National Death Registration and Forensics Medicine census data were employed. We use forensic medicine data to calculate the incidence of non-fatal injuries and years lost due to disability (YLD). The cause of death and non-fatal injuries was classified using ICD-10 codes and 23 groupes of global burden of diseases (GBD) 2010. The disability-adjusted life year (DALY) estimated on the guidelines of the GBD 2010 and age and sex structure was taken from the National Statistic Center for the year 2010. Overall, 70.8% of the subjects were males. The fatal and non-fatal injury rates of RTI were 51.3 and 283.6 per 100,000 persons, respectively. YLLs and YLDs were 46613 (24.5 per 1000) and 3405 (1.8 per 1000) in both sexes, respectively. The disability adjusted life years were 40711 in males, 9306 in females and 50018 in both sexes (42.5, 9.8 and 26.3 per 1000, respectively). More than 93% of DALY was from YLL (24.5 per 1000), with a small proportion for YLD (1.8 per 1000). Accounting for more than 50,000 DALY attributed to RTIs, traffic injuries is a major public health and socioeconomic problem in Kermanshah. Designing cost-effective interventions based on comprehensive and multi-sectoral programmes at the national and provincial levels can save many lives and resources that are lost every year. Undoubtedly, establishing a surveillance system at the sub-national level and measuring the burden of injuries, as in this study, can help policy-makers and planners in lessening the burden of RTIs. [ABSTRACT FROM AUTHOR]

The article proposes a two-staged modelling approach to identify the association between one vehicle's attributes, as well as roadway engineering, environmental and crash characteristics, and the injury severity of occupants in the partnering vehicle in two-vehicle crashes. The modelling approach uses a bivariate binary probit model, and crash data for Toronto, to first determine the probability of injury and no injury occurring, followed by the use of a bivariate ordered probit model to investigate the conditional probability of the specific severity level. Vehicles in two-vehicle crashes are categorized as “not-at-fault” (NAF) or “at-fault” (AF) and their occupants also categorized as such. The findings demonstrate that the modelling approach used in this study can reveal meaningful insights by improving understanding of how the same attribute could behave differently for NAF and AF vehicles. For example, factors found to be associated with increased probability of more severe injuries of NAF vehicle occupants are inattentive driving, left-turn movement, heavy vehicle type of the AF vehicle, and angle and rear-end impact type; conversely, for AF vehicles, their probability of more severe injury is positively associated with inattentive driving and heavy vehicle type of the NAF vehicle, and angle and approaching impact type. [ABSTRACT FROM AUTHOR]

Selective omission is necessary for road network generalisation. This study investigates the use of supervised learning approaches for selective omission in a road network. To be specific, at first, the properties to measure the importance of a road in the network are viewed as input attributes, and the decision of such a road is retained or not at a specific scale is viewed as an output class; then, a number of samples with known input and output are used to train a classifier; finally, this classifier can be used to determine whether other roads to be retained or not. In this study, a total of nine supervised learning approaches, i.e., ID3, C4·5, CRT, Random Tree, support vector machine (SVM), naive Bayes (NB),K-nearest neighbour (KNN), multilayer perception (MP) and binary logistic regression (BLR), are applied to three road networks for selective omission. The performances of these approaches are evaluated by both quantitative assessment and visual inception. Results show that: (1) in most cases, these approaches are effective and their classification accuracy is between 70% and 90%; (2) most of these approaches have similar performances, and they do not have any statistically significant difference; (3) but sometimes, ID3 and BLR performs significantly better than NB and SVM; NB and KNN perform significantly worse than MP, SVM and BLR. [ABSTRACT FROM PUBLISHER]

We estimate households’ willingness-to-pay for rural feeder roads in Ethiopia. Using purposefully collected data, we compare the economic behaviour of households by remoteness to estimate the benefits of access to feeder roads. Although we cannot definitively assert a causal relationship, we cautiously estimate that gravel roads have internal rates of return of 12–35 per cent. These results suggest that rural feeder roads may have relatively high rates of return even in unfavourable settings where (a) small-scale farmers have low levels of marketed agricultural surplus, (b) non-farm earning opportunities are negligible, and (c) motorised transport services are not guaranteed. [ABSTRACT FROM AUTHOR]

In recent years, many resource allocation models have been developed to protect critical infrastructure by maximizing system resiliency or minimizing its vulnerability to disasters or disruptions. However, these are often computationally intensive and require simplifying assumptions and approximations. In this study, we develop a robust and representative, yet tractable, model for optimizing maintenance planning of generic network-structured systems(transportation, water, power, communication). The proposed modeling framework examines models that consider both linear and nonlinear objective functions and enhances their structure through suitable manipulations. Moreover, the designed models inherently capture the network topography and the stochastic nature of disruptions and can be applied to network-structured systems where performance is assessed based on network flow efficiency and mobility. The developed models are applied to the Istanbul highway system in order to assess their relative computational effectiveness and robustness using several test cases that consider single- and multiple-treatment types, and the problems are solved on the NEOS server using different available software. The results demonstrate that our models are capable of obtaining optimal solutions within a very short time. Furthermore, the linear model is shown to yield a good approximation to the nonlinear model (it determined solutions within 0.3% of optimality, on average). Managerial insights are provided in regard to the optimal policies obtained, which generally appear to favor selecting fewer links and applying a higher quality treatment to them. [ABSTRACT FROM AUTHOR]

Hyeonmyeong Jeon, et al., from the Republic of Korea have sent in an essay on the factors affecting injury severity and the number of vehicles involved in a freeway traffic accident. The present issue contains several submissions which attest to the fact of an increase in the number of fruitful collaborations between researchers in various countries. Zhipeng Peng, et al., from China have sent in a paper which discusses the factors influencing injury severity of crashes in both, the day time and the night time, on a mountainous expressway in China. [Extracted from the article]

Our road and highway system has become a source of multiple types of “big data.” One such type of data is travel time data obtained from vehicle reidentification systems, a type that is increasingly available due to the implementation of existing and relatively new technologies such as license-plate recognition and Bluetooth-based wireless vehicle identification. Travel time data obtained in real time from such systems are used to update estimated travel times displayed on variable message signs, and research has also been conducted that utilizes travel time data as inputs to incident detection algorithms. Implementation of such systems and prior research has primarily focused on freeways and other free-flowing roads. However, such systems for travel time data collection are also being implemented on arterials. In this research an incident detection procedure that utilizes point-to-point travel time data obtained from an arterial vehicle reidentification system is developed and evaluated. Historical travel time data provided by a Bluetooth-based travel time data collection system and reported incident data are utilized to evaluate the procedure. The results show that the procedure provides a good balance of detection and false alarm rates. [ABSTRACT FROM PUBLISHER]

Route selection is a complex issue in simulating the pedestrian’s walking behaviour during the evacuation. In many current studies, the agent-based model has been widely used to simulate the individualized behaviour, and growing concern is given to the cognitive aspects in route selection. However, the influence of incomplete spatial knowledge and the preferences for different routing strategies has not been fully considered. To represent more reliable route choice by different pedestrians, this study presents an individual cognitive evacuation behaviour model which is mainly focusing on the individual differences in routing strategy and spatial knowledge. The model consists of two major components, namely the multiple routing strategies and personalized spatial cognitive road network. Based on a review of the previous studies, the potential factors that may affect the evacuation behaviour were discussed. The quantitative relationships between these potential factors and the pedestrian’s routing preference, as well as the possibilities of recognizing different roads, were explored using the regression method. As a case study, the proposed model was implemented using the data collected from a field survey of a real outdoor event. When applied in an agent-based simulation, the implemented model will support more reliable simulation of route choices corresponding to the pedestrians’ behaviour in the real event. [ABSTRACT FROM PUBLISHER]

This paper studies the assignment of long-distance passenger traffic on a highway corridor network. First, we propose a traditional model for the long-distance traffic assignment considering interactions with local commuter traffic. It addresses the effect of local networks on highway corridors. An iterative algorithm is developed to solve for the exact solution. Then, to address the potential computational issues that arise therein, a decomposition method is proposed by introducing a new concept of corridor elasticity. An assignment procedure for long-distance passenger traffic is developed accordingly. Numerical tests show that the proposed decomposition method makes significant improvements in computational performance at a small loss of optimality. This decomposition method well approximates the exact assignment from the traditional formulation, especially when the highway corridors are near-saturation. The proposed decomposition method appears practical for application. [ABSTRACT FROM PUBLISHER]

This article presents a reliability-based evacuation route planning model that seeks to find the relationship between the clearance time, number of evacuation paths, and congestion probability during an evacuation. Most of the existing models for network evacuation assume deterministic capacity estimates for road links without taking into account the uncertainty in capacities induced by myriad external conditions. Only a handful of models exist in the literature that account for capacity uncertainty of road links. A dynamic network–based evacuation model is extended by incorporating probabilistic arc capacity constraints and a minimum-cost network flow problem is formulated that finds a lower bound on the clearance time within the framework of a chance-constrained programming technique. Network breakdown minimization principles for traffic flow in evacuation planning problem are applied and a path-based evacuation routing and scheduling model is formulated. Given the horizon time for evacuation, the model selects the evacuation paths and finds flows on the selected paths that result in the minimum congestion in the network along with the reliability of the evacuation plan. Numerical examples are presented and the effectiveness of the stochastic models in evacuation planning is discussed. It is shown that the reliability-based evacuation plan is conservative compared with plans made using a deterministic model. Stochastic models guarantee that congestion can be avoided with a higher confidence level at the cost of an increased clearance time. [ABSTRACT FROM AUTHOR]

With the implementation of the Superpave mix design method, some state highway agencies have experienced significant problems in durability of hot mix asphalt (HMA) mixtures due to lower binder content. With the adoption of revised HMA specifications for the state of Maryland, it was desired to evaluate the potential risks to both agency and contractors. This was achieved by calculating the α and β risks through the construction of operating characteristic curves. Furthermore, simulation analyses were conducted for assessing the impact of the current HMA production quality on the specification tolerances percent within specification limits and mixture pay factor. The findings of this study are based on a large set of quality control and quality acceptance data since the analyses were based on 7 consecutive years of production and paving of Superpave mixtures in the state. The risk analysis indicated that the agency bears a significant risk on accepting low-quality material, and thus changes in the current State Highway Administration specification are needed and discussed in this paper. The simulation analysis illustrated that the correlation among mixture parameters had minimal impact on pay factors. Furthermore, it was concluded that the asphalt content has a more pronounced impact on the pay factor than any other mixture property. Overall, the analysis indicated that significant changes in the acceptance specifications are needed in order to reduce the risks of accepting lower quality, or rejecting good quality, HMA mixtures. Furthermore, changes of the order of 10%, 20% even 50% in specification tolerances represent feasible and currently achievable levels of production quality by the paving industry, and thus no increase in the production cost of HMA is expected. Such change in the specification tolerances is expected to promote an overall improvement in quality of Superpave mixtures in the state and the region. The approach used in this study can be used by highway agencies and the pavement industry to evaluate risks related to the acceptance of hot asphalt mixtures. The pay factor analysis can aid in adjusting pay schedules and specification tolerances for accepting higher quality materials. [ABSTRACT FROM AUTHOR]

This study proposes a novel approach for extracting multilane roads from urban road networks in OpenStreetMap (OSM) data sets as functional high-level roads, thereby allowing comparative analyses to determine the differences between this functional hierarchy and other hierarchies. OSM road networks have high levels of detail and complex structures, but they also have large numbers of duplicated lines for the same road features, which leads to difficulties and low efficiency when extracting multilane roads using conventional methods based on the analysis and operations of line segments. To overcome these deficiencies, a polygon-based method is proposed that is based on shape analysis and Gestalt theory, which treats polygons surrounded by roads as operating elements. First, shape descriptors are calculated for each polygon in networks and are used for classification. Second, candidate multilane polygons are classified as seeds based on all the polygons used as shape descriptors by a support vector machine. Finally, based on the seed polygons, a region-growing method is proposed that connects and fills the multilane features according to Gestalt theory. An experiment using OSM data from different urban networks verified the validity of the proposed method. The method achieved good and effective extraction performance, regardless of the complexity and duplication of data sets. Thus, a comparative analysis with high-level roads extracted based on road type attributes and structural analysis was performed to demonstrate the differences between the constructed road levels and other hierarchies. [ABSTRACT FROM PUBLISHER]

This study uses a hybrid approach, combining cost–benefit analysis (CBA), multiple criteria decision analysis, and Dempster–Shafer Theory, to evaluate transport infrastructure decisions. This approach not only retains the advantages of CBA, but it also facilitates the incorporation of incomplete information into the evaluation process. A particular advantage of this hybrid approach is that it can synthesize evaluation results into an easily understood unit, namely utility. A case study of Taiwan's Tamsui-Taipei Riverside Highway Project is used to illustrate the evaluation method. The evaluation results show that, whereas government officials and city council members support the highway project, academic researchers oppose it. Overall, the decision group tends to positively approve this transport infrastructure investment. These results also reflect the actual situation in Taiwan as stakeholders grapple with the issues arising from the proposed Tamsui-Taipei Riverside Highway Project. [ABSTRACT FROM AUTHOR]

The Kansas Department of Transportation has a comprehensive pavement management system known as network optimisation system (NOS). Annual condition surveys are conducted for NOS. Currently, the structural number (SN) of flexible pavements is computed using the American association of state highway and transportation officials equation based on the centre and fifth sensor deflections of a falling weight deflectometer (FWD). However, a rolling wheel deflectometer (RWD) can be used to collect deflection data at the network-level. This study was conducted to see whether the SN of flexible pavements can be obtained from this RWD deflection and NOS condition survey results. In this study, FWD deflection data, collected from 1998 to 2006, were analysed. Multiple regression analysis was done. The results showed that there is a negative relationship between SN and centre deflection. Equations can be used to calculate SN based on FWD (or RWD) centre deflections and network-level condition survey results. The SN is more sensitive to centre deflection than the total pavement thickness. [ABSTRACT FROM AUTHOR]

Infrastructure condition assessments provide key information for monitoring the quality of infrastructure, planning and budgeting of maintenance and rehabilitation activities and establishing performance goals. Although the literature is rich in condition assessment methods for roadway pavement and bridges (and to some extent for traffic signs), it is lacking such methods for roadside assets. This paper describes the development and validation of a condition assessment method for 12 roadside asset types and maintenance activities that are related to roadway safety, drainage, cleanliness and vegetation. These assets and maintenance activities are located in the area between the outside edges of the outside shoulders and the right-of-way boundaries. On divided highways, the median is also included. The developed condition assessment method consists of a set of performance standards, a visual inspection procedure to assess compliance with these standards and a statistical analysis procedure to determine the roadside level of service. To test and validate the developed method, it was applied to five highway corridors in Texas, USA, representing different climatic conditions, topography, traffic volume and population density (urban vs. rural). These field trials provided insights into the developed method, including practicality, reproducibility and probability distribution function which best represents the sample unit score. [ABSTRACT FROM AUTHOR]

Economic efficiency is an important factor in seismic rehabilitation of road infrastructures. An inventory of structures is screened to identify seismically deficient parts and prioritise them in the order of need for rehabilitation purposes. In most cases, the financial resources for road infrastructure rehabilitation projects are limited. Therefore, there is a need to efficiently allocate resources to various projects. This article presents a multi-strategy decision support system (DSS) for seismic rehabilitation budget allocation across existing road infrastructures. This DSS employs a multi-criteria assessment module that takes into account different criteria to estimate the financial needs for rehabilitation and to establish an allocation methodology based on the available budget in a fiscal year. To select the optimal package of projects, a genetic algorithm (GA) optimisation module is developed. Multi-objective decision-making is conducted under a specific decision strategy (DS) by solving a (0–1) Knapsack problem. To demonstrate the applicability of the GA-based approach, a hypothetical decision-making problem is presented. The results reveal that the optimal package is more sensitive to the available budget and DS than to the weights of criteria and project scores. Using this system, managers can compare their decisions for different strategies and significantly improve management efficiency. [ABSTRACT FROM AUTHOR]

Asphalt paving materials are composed of over 95% aggregate by weight. Therefore, the highway engineering and construction industries annually consume large amounts of aggregate, usually obtained from natural sources. The increased demand for natural stone mining has caused the destruction of natural lands and environmental concerns. This study focused on the determination of the engineering characteristics of hot mix asphalt concrete using dacite and recycled concrete as aggregates. Formulations were tested using recycled concrete aggregate (RCA) as a partial or total replacement for dacite, including replacement of coarse aggregate (CA), fine aggregate (FA) and filler. The results showed that the optimum formulation was a mixture of dacite CA and RCA FA. The optimal mix was superior to the other tested mixes in all the evaluated properties, i.e. Marshall Stability, fatigue, permanent deformation and resilient modulus. [ABSTRACT FROM AUTHOR]

The objectives of this review-based paper were twofold. Firstly, we aimed to explore the need and possibilities for broadening the scope of highway planning by taking account of the residential context, including residential satisfaction. Satisfaction appears to be an interesting, and in our opinion, valuable mediating planning concept between road infrastructure planning and the accompanying external effects on the one hand and household coping strategies on the other. Households living near highway infrastructure are influenced by both positive (i.e. accessibility gains) and negative road-related factors (e.g. noise nuisance and air pollution). Changes in these factors may trigger people to accept the new situation, adjust preferences, try to influence plans and/or  even relocate. The second aim was to gain a greater understanding of the influence of both accessibility characteristics and negative externalities on the residential context of households. With respect to context, we make a distinction between residential satisfaction, housing prices and residential relocation. We see changes in residential satisfaction as a potential early predictor of opposition to plans, not only from active opposers but also from the more ‘silent majority’, and as a predictor of housing price changes and residential migration. Insights into residential satisfaction around highways may help transportation planners to relieve locational stress and may also prevent protests and relocations. Our literature review indicated that households prefer to live close to highways to benefit from high regional accessibility, but do not want to contend with the nuisances. This is also reflected in property values. However, the literature appears to put more emphasis on studying the impact of (regional) accessibility and externalities on location behaviour than on residential satisfaction. Because of the added value that the concept of residential satisfaction may provide in road planning, and the limited scientific insights, it is important to gain greater insight into how residential satisfaction is influenced by negative and positive externalities and into how residential satisfaction changes over time—from the stage when new road projects are discussed through to concrete planning, realization and the period after completion. Moreover, it would be worthwhile to gain a deeper understanding of the extent to which house prices, location behaviour and residential satisfaction near highways interrelate. [ABSTRACT FROM AUTHOR]

A primary motivation of this paper is to draw together, in one source, information on the nature, extent and performance of Australia's evolving toll road network which is currently spread across many disparate published and unpublished sources. This paper provides key information (e.g. length, toll rates, year opened, operator(s) and payment alternatives) on all of the fully interoperable toll roads in Australia that are present in Sydney (e.g. the M2, M4, M5, etc.), Melbourne (CityLink and EastLink) and Brisbane (the Gateway Bridge, the Logan Motorway and the Gateway Extension). Where available, we compare and discuss actual traffic levels and forecasts, revealing the sizeable gap or 'error' in forecasts, especially during the first year of operation. Ordinary least squares regression and panel random effects regression models are developed to identify potential sources of explanation of differences in error forecasts between the Australian toll roads at various points post the opening date. A separate analysis of a sample of toll roads in the USA was also undertaken that supports the main findings from the Australian toll road network. Key influences on errors in forecasts are the capacity of a toll road, the elapsed time that the toll road has been in place, the specific period of time in which a tolled road is introduced into the network (which influences the complexity of route options including multiple tolled routes and hence toll saturation), the length of the tolled route, the presence of cash payment and the charging regime (i.e. fixed vs. distance-based or variable user tolls). [ABSTRACT FROM AUTHOR]