Highway In China Research Articles

PROTOCOL: Evidence and gap map: studies of the effectiveness of transport sector interventions in low- and middle-income countries.

PROTOCOL: Evidence and gap map: studies of the effectiveness of transport sector interventions in low- and middle-income countries.

Application of asphalt rubber cape seal as asphalt pavement surface course for rehabilitated trunk highway in east Gansu

Although been frequently used as a preventative maintenance measure for asphalt pavements, the Cape seal process has not been widely adopted as a possible alternative for rehabilitated pavement. This research evaluated the feasibility of applying asphalt rubber Cape seal structure into the surface course of reconstructed highway in west China. The Cape seal is composed of 11-16 mm chips spread over asphalt rubber membrane sprayed in advance, by which followed a micro surfacing layer with SBR latex modified asphalt emulsion. Based on a test section in the Banxiao highway project, the construction of asphalt rubber Cape seal and micro-surfacing were investigated experimentally. In addition, to guide the engineers, major issues during construction of the Cape seal were discussed and corresponding countermeasures were suggested.

Research on Mechanical Response of Pavement Structure to Differential Settlement of Subgrade on Highway Widening

Based on the widening project of Ri‐Lan highway in China, the finite element model is established by PLAXIS. By applying differential settlement at the bottom of the pavement, the mechanical response of the pavement structure is analysed. Finally, the differential settlement control standard indicated by crack strength is proposed. The results show that, under the effect of differential settlement, within about 4 cm of old pavement surface and upper base bear tensile stress, the base first reaches the failure strength. Under 4 cm of the old pavement surface, the subbase first reaches the failure strength. The differential settlement control standard of the pavement structure is determined by the splitting strength of the material, and we, respectively, control the differential settlement of less than 23.4 mm, where the corresponding cross‐slope rate is 0.33%, and below 75.2 mm, where the corresponding cross‐slope rate is 0.54%. It could support practical engineering applications.

Expressway Exit Traffic Flow Prediction for ETC and MTC Charging System Based on Entry Traffic Flows and LSTM Model

The Expressway (controlled-access highways) of China is the longest in the world and plays an important role in people’s daily life. Accurate short-term traffic prediction is essential for travel schedule and active traffic management. There are two coexisting charging systems for expressway in China, Electronic Toll Collection (ETC) and Manual Toll Collection (MTC), which have different passing capacity and variation pattern. In this work, we demonstrate that the exit traffic flow prediction at Shanghai Xinqiao toll station using entry traffic flows from multiple close-related stations with Long Short-Term Memory (LSTM) model. Based on the origin-destination (OD) traffic data of a month, we present a new method to predict the exit station’s traffic flow in the future 5 minutes. After deleting abnormal data, we select 12 of the 109 entry toll stations for the experiment. The traffic flow of these 12 entry stations account for 86% of the total exit traffic flow. This method uses the spatial-temporal matrix to deal with different three scenes that are ETC and MTC charging systems individually, the mix of ETC and MTC. We use the LSTM model with various lengths of flow sequence and amounts of hidden layer neurons for three different scenes. Lastly, we validate our model and carefully select the hyperparameters for better prediction accuracy by three evaluation metrics. The experimental results demonstrate that predicting the ETC is the best in the three scenes.

Analysis and Prediction of Overloaded Extra-Heavy Vehicles for Highway Safety Using Machine Learning

Along with the prosperity and rapid development of the national economy, the transportation industry has rapidly developed in China. However, overloaded vehicles have been causing frequent traffic accidents. Thus, to alleviate or resolve the corresponding problems associated with highway engineering safety and the market economy, an improved technique for overload management is urgently required. In this study, to analyze the overload data on expressways and highways in China, we developed a machine learning model by comparing the performances of cluster analysis, backpropagation neural network (BPNN), generalized regression neural network (GRNN), and wavelet neural network (WNN) in analyzing global and local time series overload data. In a case study, our results revealed the trends of overloading on highways in Jiangsu Province. Given sufficient data, BPNN performed better than GRNN and WNN. As the amount of training data increased, GRNN performed better, but the runtime increased. WNN had the shortest runtime among the three methods and could reflect the future trends of the overload rate in the monthly data prediction of overload. Our model provides information with potential value for expressway network management departments through data mining. This information could help management departments allocate resources reasonably and optimize the information utilization rate.

Highway Concrete Guardrail Lifting Scheme and Safety Performance Verification

In order to achieve the old fence of reuse, improve the safety performance of guardrail, barrier structure does not meet the requirements, make full use of the old concrete guardrail on the basis of heightening, through computer simulation experiment were analyzed, and optimization design, through the real car collision test, make the concrete guardrail after heightening structure satisfies the requirement of the safety performance of current specification. The results show that the protective performance of the two guardrail schemes meets the requirements of the current guardrail evaluation standards through the computer simulation experiment. Through the optimized design of scheme 1, the actual car crash test proves that the enhanced structure of Minhua TYPE II concrete guardrail can meet the requirements of safety performance evaluation. The research results provide an important basis for the transformation of the guardrail and the revision of the current design of expressway in China.

Technical Project of an Electrified Highway in China

This study introduces the system research and technical demonstration of electrified highway and electric freight vehicle technology worldwide. In combination with China's highway freight traffic, overload of some vehicles, and the actual electrified technological situation of different traction locomotives in China, a Chinese electrified highway technical solution about dual or three source (petrol-electric hybrid)-trolley electric truck based on the overhead contact line power supply is proposed. This solution includes the electrification topological structure, highly efficient drive technology, energy intelligent management technology of online charging, intelligent control technology of pantograph, and high voltage power supply technology meeting the charging demand of heavy duty trucks on the electrified highway. These technologies have solved the key technical problems, such as large flow rate of electric trucks, small actual carrying capacity of the power supply network, and easy trip of wayside substations in China. A small-scale road test has been carried out in Suzhou, China. The study results have important guiding significance for the further research and developmental test and demonstration of electrified highway technology in China.

Damage by wind-blown sand and its control measures along the Taklimakan Desert Highway in China

Desertification is one of the most serious environmental problems in the world, especially in the arid desert regions. Combating desertification, therefore, is an urgent task on a regional or even global scale. The Taklimakan Desert in China is the second largest mobile desert in the world and has been called the “Dead Sea” due to few organisms can exist in such a harsh environment. The Taklimakan Desert Highway, the longest desert highway (a total length of 446 km) across the mobile desert in the world, was built in the 1990s within the Taklimakan Desert. It has an important strategic significance regarding oil and gas resources exploration and plays a vital role in the socio-economic development of southern Xinjiang, China. However, wind-blow sand seriously damages the smoothness of the desert highway and, in this case, mechanical sand control system (including sand barrier fences and straw checkerboards) was used early in the life of the desert highway to protect the road. Unfortunately, more than 70% of the sand barrier fences and straw checkerboards have lost their functions, and the desert highway has often been buried and frequently blocked since 1999. To solve this problem, a long artificial shelterbelt with the length of 437 km was built along the desert highway since 2000. However, some potential problems still exist for the sustainable development of the desert highway, such as water shortage, strong sandstorms, extreme environmental characteristics and large maintenance costs. The study aims to provide an overview of the damages caused by wind-blown sand and the effects of sand control measures along the Taklimakan Desert Highway. Ultimately, we provide some suggestions for the biological sand control system to ensure the sustainable development of the Taklimakan Desert Highway, such as screening drought-resistant species to reduce the irrigation requirement and ensure the sound development of groundwater, screening halophytes to restore vegetation in the case of soil salinization, and planting cash crops, such as Cistanche, Wolfberry, Apocynum and other cash crops to decrease the high cost of maintenance on highways and shelterbelts.

A new perspective of link prediction in complex network for improving reliability

Link prediction is an important issue for network evolution. For many real networks, future link prediction is the key to network development. Experience shows that improving reliability is an important trend of network evolution. Therefore, we consider it from a new perspective and propose a method for predicting new links of evolution networks. The proposed network reliability growth (NRG) model comprehensively considers the factors related to network structure, including the degree, neighbor nodes and distance. Our aim is to improve the reliability in link prediction. In experiments, we apply China high-speed railway network, China highway network and scale-free networks as examples. The results show that the proposed method has better prediction performance for different evaluation indexes. Compared with the other methods, such as CN, RA, PA, ACT, CT and NN, the proposed method has large growth rate and makes the reliability reach the maximum at first which save network construction resources, cost and improve efficiency. The proposed method tends to develop the network towards homogeneous network. In real networks, this structure with stronger stability is the goal of network construction. Therefore, our method is the best to improve network reliability quickly and effectively.

Analyses of the defects in highway tunnels in China

The number and length of highways in China far exceed those in other countries. Therefore, to better understand the defects that have occurred in Chinese highways that are currently in service, we collected data on the defects in 90 such tunnels. Using these data, we conducted a systematic study on the causes of such defects. Based on the characteristics thus obtained, the defects could be divided into seven categories: structural deformation, structural damage, material deterioration, water leakage, frost damage, construction defects, and others (accessory facility defects). The results reveal that lining cracks and water leakage are the most common defects in the highway tunnels of China. These tunnel defects can be categorized based on their risk, correlations, visibility, regional characteristics, and progressive nature. Human activities are the primary cause of highway tunnel defects. The treatment measures for such tunnel defects in China can be categorized as additional, repair, and replacement measures; these measures are selected based on actual requirements of addressing the defects. Lastly, corresponding preventive measures and disposal procedures are established based on the abovementioned analyses. The results of this study are expected to serve as a reference and provide significant guidance for the prevention and treatment of road tunnel defects.

LCA and LCCA based multi-objective optimization of pavement maintenance

With growing maintenance demands whereas limited budgets, an integrated methodology unifying life-cycle assessment (LCA), life cycle cost assessment (LCCA) and multi-objective optimization is proposed to establish maintenance decision-making system, considering performance, economic as well as environmental dimensions. Firstly, system scope and unit process of the methodology are redefined considering pavement industry in China. Next, assessment models and parameters are determined to establish the inventory. Then, LCCA is adopted to convert environmental footprint into an economically measurable unit - environmental damage cost (EDC). Lastly, a programming optimization is executed to obtain the optimal maintenance schedule over the whole pavement life cycle. To verify, a case study based on an existing highway in southeast China is conducted, considering ECA-10 thin overly (ECA-10), milling and resurfacing the upper layer (MRU) and hot-in-place rehabilitation (HR) strategies. Results indicate that user cost is the dominant factor whereas environmental impact is relatively negligible. Pavement design life and service life of maintenance alternatives have significant influence on the optimal schedule, and longer pavement design life should be considered when conducting LCA-based programming optimization. With the extension of design life, MRU shows the best long-term benefit. Materials and construction are the main stages potentially improved. Few attempts have been made to introduce LCA into the pavement industry of China, but this model successfully contributes to sustainability goal and scientific decision-making.

Dynamic Reliability of Continuous Rigid-Frame Bridges under Stochastic Moving Vehicle Loads

The current volume of freight traffic has increased significantly during the past decades, impacted by the fast development of the national transportation market. As a result, the phenomena of truck overloading and traffic congestion emerge, which have resulted in numerous bridge collapse events or damage due to truck overloading. Thus, it is an urgent task to evaluate bridge safety under actual traffic loads. This study evaluated probabilistic dynamic load effects on rigid-frame bridges under highway traffic monitoring loads. The site-specific traffic monitoring data of a highway in China were utilized to establish stochastic traffic models. The dynamic effect was considered in a vehicle-bridge coupled vibration model, and the probability estimation was conducted based on the first-passage criterion of the girder deflection. The prototype bridge is a continuous rigid-frame bridge with a midspan length of 200 m and a pier height of 182 m. It is demonstrated that the dynamic traffic load effect follows Gaussian distribution, which can be treated as a stationary random process. The mean value and standard deviation of the deflections are 0.071 m and 0.088 m, respectively. The dynamic reliability index for the first passage of girder deflection is 6.45 for the current traffic condition. However, the reliability index decreases to 5.60 in the bridge lifetime, accounting for an average traffic volume growth ratio of 3.6%.

Travellers’ meaning-making of the Sichuan-Tibet highway: from space of flows to place

The relationship between mobility and place-making in the context of tourism based on the new mobilities paradigm has been explored. Taking road travel on the Sichuan-Tibet Highway in southwestern China as a case, auto-ethnography and mobile ethnography are employed as the primary research methods, along with in-depth interviews, observations, personal travel log writings, and second-hand data collection. The question that how the space of road becomes a meaningful place through the mobility of road travellers thus has been answered. The mobility pattern of travellers is found to be stable in the time dimension and there are periodic repetitions in the spatial dimension, making ‘place-ballet’ on the highway. Accordingly, the road changes from space of flows into a place that is richly endowed with meaning. The travellers’ imagination of the road plays an important role in their interactions with the road, helping them making the meaning of the road. Multiple mobility practices shape the traveller’s ‘sense of the road’. In particular, the road is not a homogenous space in motion, but a ‘wrinkled’ one with numerous anchoring points. These moorings such as restaurants, hostels and landmarks shape travellers’ emotional connection with the road. Proactive or forced stillness not only affect the pace of the traveller’s mobility, but also broadens their understanding of the road and road travel. Therefore, the meaning attributed to the road is constructed by the mobility and the moorings. Accordingly, a comprehensive understanding of road travel, which is a distinct form of mobility practice, is generated. Moreover, the understanding of roads as a space of flows has been deepened and the significance of travel channels within mobility studies is highlighted. Finally, roads are regarded as a meaning place, which contributes to forming a ‘mobile concept’ of the place.

Yuanfen and traveling neo‐tribes: Social interactions and group relations among Chinese road travelers

AbstractWithin the context of Chinese culture and the theoretical framework of neo‐tribes, this study explores the mobilities of road travelers on the Sichuan‐Tibet Highway in China and explains their social interactions and group relations by using mobile ethnography and multi‐sited ethnography. It finds that social interactions during road travels are “easily meet, easily part.” However, between travelers and within travel groups, kindness and affective interactions are ubiquitous. The Chinese cultural concept “yuanfen,” which means serendipity in relationships, explains the logic of interaction. A road traveling neo‐tribe is also formed. The findings of this study enhance understanding of alternative travelers' social interactions and tourism experiences.

Ranking contributors to traffic crashes on mountainous freeways from an incomplete dataset: A sequential approach of multivariate imputation by chained equations and random forest classifier

The estimation of the effect of contributors to crash injury severity and the prediction of crash injury severity outcomes suffer often from biases related to missing data in crash datasets that contain incomplete records. As both estimation and prediction would greatly improve if the missing values were recovered, this study proposes a sequential approach to handle incomplete crash datasets and rank contributors to the injury severity of crashes on mountainous freeways in China. The sequential approach consists of two parts: (i) multivariate imputation by chained equations imputes the missing values of independent variables; (ii) a random forest classifier analyses the correlation between the dependent and the independent variables. The first part considers different imputation methods in light of the independent variables being either binary, categorical or continuous, whereas the second part classifies the correlations according to the random forest classifier. The proposed method was applied to the case-study about mountainous freeways in China and compared to the analysis of the raw dataset to evaluate its effectiveness, and the results illustrate that the method improves significantly the classification accuracy when compared with existing methods. Moreover, the classifier ranked the contributors to the injury severity of traffic crashes on mountainous freeways: in order of importance vehicle type, crash type, road longitudinal gradient, crash cause, curve radius, and deflection angles. Interestingly, a lower importance was found for environmental factors.

INFLUENCE MECHANISM OF VISUAL PERCEPTION OF EDGE RATE LINES CYCLE LENGTH ON DRIVER’S SPEED

It is known that the installation of edge rate lines can help reduce driving speed. Theoretically, higher edge rate density leads to higher perception speed, so as the effect of speed reduction. However, there has not been a successful evaluation of appropriate design cycle length requirements. A series of experiments were taken on the straight sections on Hangrui highway in China. The cycle length was separately set in different values of 16, 8, 4, 2 and 1 m. The results showed that cycle length had significantly influence on the speed reduction effect. When the length of spatial edge rate line in each cycle λ equalled to the value of 16, 8, 4, 2 m, the effect of speed reduction was significantly enhanced as λ decreased. Percent of average speed reduction was 0.8, 3.0, 5.8 and 7.4%, respectively. However, when λ = 1 m, speed reduction effect was weaker than λ = 2 m, reduction percent of average speed was 5.2%. Then, relations between acceleration and average edge rate was analysed. When temporal frequency of edge rate lines fell in (10 Hz, 19 Hz], the braking deceleration of drivers increased as the temporal frequency increased, which conformed to the relation between temporal frequency and perception speed; when temporal frequency was lower than 10 Hz, some drivers will speed up. It may be related to the threshold of perception speed difference; when temporal frequency was higher than 19 Hz, some drivers will speed up. It may be related to flicker fusion phenomenon. According to the experiments results, edge rate lines cycle length for future implementations should be determined by the speed distribution of the target road.

Effects of peripheral transverse line markings on drivers’ speed and headway choice and crash risk in car-following: A naturalistic observation study

Rear-end crashes are closely related to car-following situation of vehicles. Speeding and insufficient headway are the major reasons as the drivers have not enough time to react to a sudden brake from the leading vehicle. Perceptual countermeasures, like speed reduction markings, are widely used in practice for accident prevention, and are verified with substantial effectiveness. However, compared with its practical application, the perceptual countermeasures are rarely analyzed in depth from the perspective of drivers’ visual perception where the meaning of “perceptual” actually dwells. In addition, its effect on drivers’ headway (distance) choice is almost ignored in previous research. Given this, the present study explored the effects of a certain type of perceptual treatment, i.e., the peripheral transverse line markings (PTLMs), on drivers’ choice of speed and headway (distance) in car-following by a series of on-road experiments. In the on-road experiments, temporary line markings were installed on a real-world freeway in China to shape the PTLMs. The intersection angle (α) and the longitudinal spacing (λ) of the PTLMs were manipulated to attempt to associate the line markings with drivers’ visual perception. Results of general and sectional relative differences of time headway (ηh, θh), speed (ηv, θv), and distance (ηd, θd) suggests that 1) the speed was reduced, the distance and time headway were increased significantly after the installation of PTLMs when compared with the original condition; 2) a larger intersection angle (α) and a smaller longitudinal spacing (λ) of PTLMs could lead to a greater variations in speed and headway (distance); in particular, the PTLMs in a form of α=150°, λ=2m resulted in 0.44 s increase in time headway, 1.33 m/s reduction in speed, and 4.07 m increase in distance in maximum; 3) the real-time crash risk variations under the influence of PTLMs were evaluated by two modified and extended surrogate safety indicators. The effects of PTLMs were discussed and explained considering the influences of optical illusion on lane width narrowing, edge rate on speed and “discontinuity effect” on distance, respectively. The findings of this study provide theoretical support for the perceptual countermeasures and suggest comparative advantages of PTLMs in dealing with rear-end crashes by intervening drivers’ speed and headway choice.

Study on the Application of Expressway Construction Based on Sponge City Concept

<p>Currently, in the active trial stage, sponge city concept has been applied in many low-impact development facilities on expressways in China, but many applications are not widely used. From four angles of pavement, slope, interchange and service area of expressway, this paper explains the adverse effects brought by rainwater, and then gives, and it carries out scene analysis combined with actual engineering projects with some feasible application schemes. Finally, the concept of sponge city at present is summarized, and it is considered that the optimal planning and design can be made only after establishing a reliable mathematical model and carrying out quantitative analysis.</p>

Real-Time Monitoring Method for Layered Compaction Quality of Loess Subgrade Based on Hydraulic Compactor Reinforcement.

Hydraulic compactor is an efficient reinforcement machine for loess subgrade. However, it is difficult to control the layered compaction quality of the subgrade. This research presents a real-time layered compactness monitoring method for hydraulic compactor reinforcement of subgrade in loess areas. The hydraulic force coefficient is first introduced, and the dynamic response model of the hydraulic rammer and soil is established. The relationship between the acceleration of the hydraulic rammer and the compactness of subgrade is then obtained based on the collision theory in elastic half space. A full-scale test using a hydraulic compactor to reinforce loess subgrade was also carried out. Results show that the hydraulic compactor obtains the effective influence depth for the reinforcement of loess subgrade. Within the effective reinforcement depth, the relationship between the peak acceleration of the rammer and the layered compactness of subgrade can be well fitted by a quadratic function model. The layered compactness of the subgrade and the working state of the hydraulic compactor can then be remotely monitored at a mobile terminal in real time. Furthermore, the monitoring technology was applied to Huangling-Yan’an Expressway in China, significantly improving the accuracy and efficiency of real-time monitoring of the layered compactness of subgrade in the loess area.

Probabilistic evaluation of maximum dynamic traffic load effects on cable-supported bridges under actual heavy traffic loads

The traffic load has grown significantly in recent years, which might be a threat for the service safety of existing bridges. Thus, it is an urgent task to assess the actual traffic load effects on bridges, considering actual heavy traffic load instead of design traffic load. This study presents a framework for extrapolating maximum dynamic traffic load effects on large bridges using site-specific traffic monitoring data. The framework involves vehicle–bridge interaction analysis and probabilistic modelling of extreme values. The weigh-in-motion measurements of a busy highway in China were collected for stochastic traffic load modelling. Case studies of two long-span cable-supported bridge based on the weigh-in-motion measurements were conducted to demonstrate the effectiveness of the proposed framework. It is demonstrated that Rice’s level-crossing approach can capture both dynamic and probabilistic characteristics of the traffic load effects. The root-mean-square displacement of the cable-stayed bridge follows a C-type distribution, and the one for the suspension bridge follows an M-type distribution, which is associated with the first-order mode shapes of the two types of bridges. The amplification factors for the cable-stayed bridge and the suspension bridge are 5.9% and 3.6%, respectively. The numerical analysis indicates that the dynamic effect for extrapolation is weaker with the increase in bridge span length, but the effect of traffic volume growth will be more significant.