DEPTH PREDICTION OF RAIN WATER ON ROAD SURFACE BASED ON ARTIFICIAL NEURAL NETWORK

A model based on the non-linear artificial neural network （ANN） is established to predict the thickness of the water film on road surfaces. The weight and the threshold can be determined by training test data, and the water film thickness on the road surface can be accurately predicted by the empirical verification based on sample data. Results show that the proposed ANN model is feasible to predict the water film thickness of the road surface.

SIMULATION ANALYSIS OF INFLUENCE OF ROAD SURFACE ROUGHNESS ON TYRE DYNAMIC PERFORMANCE IN AUTOMOTIVE BRAKING

Using a nonlinear time varying tyre model, this paper simulatively analyzes the influence of road surface roughness amplitude and road spatial frequency on automobile ground adhesion ability. The result shows that with the increase of road surface roughness, the tyre adhesion ability declines, and the automotive braking distance increases. Moreover, the reliability of the nonlinear time varying tyre model in reflecting the influence of the road surface roughness is validated. It is testified that this model is an effective dynamic one in the simulation of automotive braking performance on uneven road.

Automated extraction of expressway road surface from mobile laser scanning data

This paper presents a voxel-based region growing method for automatic road surface extraction from mobile laser scanning point clouds in an expressway environment.The proposed method has three major steps:constructing a voxel model;extracting the road surface points by employing the voxel-based segmentation algorithm;refining the road boundary using the curb-based segmentation algorithm.To evaluate the accuracy of the proposed method,the two-point cloud datasets of two typical test sites in an expressway environment consisting of flat and bumpy surfaces with a high slope were used.The proposed algorithm extracted the road surface successfully with high accuracy.There was an average recall of 99.5%,the precision was 96.3%,and the F1 score was 97.9%.From the extracted road surface,a framework for the estimation of road roughness was proposed.Good agreement was achieved when comparing the results of the road roughness map with the visual image,indicating the feasibility and effectiveness of the proposed framework.

New Method of Road Surface Identification in Anti-Lock Braking System

Based on the vehicle-road dynamic model, the road characteristic parameter, which depends on different types of road surfaces, is introduced and a new method of road surface identification for automotive anti-lock braking system (ABS) is proposed. According to the characteristics of vehicle-road dynamic model, a simple math resolution method of the model's factors is established. Only using the information of wheel speed, the vehicle reference velocity and the wheel slip ratio are estimated real-timely. And based on the wheel dynamic model, the road characteristic parameter is determined to identify the road surface for the determination of thresholds of ABS regulative parameters. With this new method, the road surface identification can be accurately obtained and calculation time is short that it can meet the ABS real time control need, and it also improves the performance of ABS.

Change Characteristics and Forecast Research of Road Surface Temperature on Huyu Expressway (Hubei Section)

In this paper,the monitoring data of road surface temperature,air temperature,wind speed,wind direction,relative humidity and precipitation from the automatic weather stations of Hurongxi,Hanyi,Wuhuang and Huanghuang on Huyu expressway from June 2013 to August 2014 were used to investigate the change characteristics of different sections' road surface temperatures in different seasons and sky conditions. The forecast models of the maximum and minimum road surface temperatures were established on different sections by statistical analysis methods,and the forecast results were verified. The results showed that the road surface temperature and air temperature of Hurongxi,Hanyi,Wuhuang and Huanghuang displayed obvious diurnal variation,but the difference between the road surface temperature and air temperature was larger. Compared with the other three sections,the maximum difference between the road surface temperature and air temperature on Hurongxi increased in winter and decreased in summer overall. The road surface temperature was close to air temperature on Hurongxi after sunset on sunny to cloudy and overcast in winter,while less than air temperature on Hanyi,Wuhuang and Huanghuang. The air temperature was less than road surface temperature on the four sections on rainy day and significant on Hurongxi. In summer,the air temperature was less than road surface temperature on the four sections under three sky conditions and the difference between them in afternoon was the biggest on sunny to cloudy and overcast. The road surface temperature was very close to each other among the four sections in January,while which was rising with the decrease of altitude in April,July and October. The forecast result of the road surface temperature was close to actual result on Hurongxi and Huanghuang,so which can be for reference. But there were some big errors between the forecast result and actual result in several timings on Hanyi and Wuhuang,so the forecast result should be corrected for actual business work.

Multi-objective genetic algorithm for the optimization of road surface cleaning process

The parameters affecting road surface cleaning using waterjets were researched and a fuzzy neural network method of calculating cleaning rate was provided. A genetic algorithm was used to configure the cleaning parameters of pressure, standoff distance, traverse rate and angle of nozzles for the optimization of the cleaning effectiveness, efficiency, energy and water con-sumption, and a multi-objective optimization model was established. After calculation, the optimized results and the trend of variation of cleaning effectiveness, efficiency, energy and water consumption in different weighting factors were analyzed.

Evaluation of Tactile Ground Surface Indicators Installed on Sidewalks Beside Ninghai Road of Nanjing Based on Fuzzy Comprehensive Evaluation

In recent years,tactile ground surface indicators have been vigorously constructed in all cities and towns in China,and the length of tactile ground surface indicators has been regarded as one of the standards for measuring urban civilization construction.However,there are many problems in the actual use of tactile ground surface indicators,and the construction of a large number of tactile ground surface indicators has not had a positive impact on the travel of the visually impaired.With the sidewalk of Ninghai Road in Nanjing,Jiangsu,China as the object of study,this study constructed an evaluation system of tactile ground surface indicators installed on the sidewalk beside a road and determined its weight,evaluated the tactile ground surface indicators installed on sidewalks beside Ninghai Road from the perspective of the visually impaired,using fuzzy comprehensive evaluation,and obtained the satisfaction of each indicator and analyzed the reasons of the indicator results.This set of evaluation system can provide basic ideas for the targeted evaluation of tactile ground surface indicators installed on the sidewalk beside a road based on different urban districts,different urban road grades,and different urban environmental conditions.

Bamboo Fiber Modified Asphalt Mixture Proportion Design and Road Performances Based on Response Surface Method

In order to comprehensively utilize the remaining bamboo residue of bamboo products,this paper presents a research on recycling the bamboo fibers from bamboo residue for improving the performance of the asphalt mixtures.First of all,the basic performance parameters of sinocalamus affinis fiber,phyllostachys pubescens fiber,green bamboo fiber were tested and analyzed,and the optimal content and length were put forward.Then,the mix ratio design of the bamboo fiber modified asphalt mixture was further designed through the response surface method,and was verified the rationality of the mix ratio.Finally,the mixture specimens were made according to the experimental design mix ratio,and the high temperature,low temperature performance and moisture susceptibility of the bamboo fiber modified mixtures asphalt were tested.The results showed that the high temperature performance,low temperature performance and moisture susceptibility of bamboo fiber modified asphalt mixtures were improved compared with the performance of SBS modified asphalt mixture.When the length of bamboo fiber is 7.25 mm and the content of 0.22%,the road performance of the asphalt mixture was optimal.Consequentially,the decomposition of bamboo residue into bamboo fiber and its application in asphalt pavement can improve the reuse of bamboo waste,with remarkable environmental benefits and great promotion value.

Developing a Durable Quiet Road Surface

Road traffic noise can have a significant impact on the quality of life for residents close to major road networks.One of the most effective measures for reducing the noise from road traffic,particularly on high-speed roads,is to ensure the use of a low noise road surface.Research on pavement construction and the measurement of its acoustic properties has shown that significant noise reductions can be achieved through the use of certain road surface types.However certain low noise road surfaces do not exhibit the desired durability associated with more traditional pavements,leading to costly and disruptive maintenance regimes.This article looks at the mechanisms involved in tyre/road noise generation and how these interact with various road surface properties including a brief overview of some common surface types.It then goes on to explain how these concepts informed the development of an asphalt surfacing material with enhanced durability and good acoustic performance without compromising safety.Progress in testing the resulting Premium Asphalt Surfacing System(PASS)is outlined,including the completion of a successful network trial.

A Comprehensive Evaluation of State-of-the-Art Deep Learning Models for Road Surface Type Classification

In recent years,as intelligent transportation systems(ITS)such as autonomous driving and advanced driver-assistance systems have become more popular,there has been a rise in the need for different sources of traffic situation data.The classification of the road surface type,also known as the RST,is among the most essential of these situational data and can be utilized across the entirety of the ITS domain.Recently,the benefits of deep learning(DL)approaches for sensor-based RST classification have been demonstrated by automatic feature extraction without manual methods.The ability to extract important features is vital in making RST classification more accurate.This work investigates the most recent advances in DL algorithms for sensor-based RST classification and explores appropriate feature extraction models.We used different convolutional neural networks to understand the functional architecture better;we constructed an enhanced DL model called SE-ResNet,which uses residual connections and squeeze-and-excitation mod-ules to improve the classification performance.Comparative experiments with a publicly available benchmark dataset,the passive vehicular sensors dataset,have shown that SE-ResNet outperforms other state-of-the-art models.The proposed model achieved the highest accuracy of 98.41%and the highest F1-score of 98.19%when classifying surfaces into segments of dirt,cobblestone,or asphalt roads.Moreover,the proposed model significantly outperforms DL networks(CNN,LSTM,and CNN-LSTM).The proposed RE-ResNet achieved the classification accuracies of asphalt roads at 98.98,cobblestone roads at 97.02,and dirt roads at 99.56%,respectively.

Road Surface Condition and Monitoring System Utilizing Motorcycle(ROCOM)—System Development,Validation and Field Test

Motorcycles are the riskiest mode of travel in Malaysia,however motorcycles are also very sensitive to the road surface condition.Thus,by taking advantage of this,a system of software applications that analyses motorcycle motion and mapped out risky road sections was developed,i.e.ROCOM.The system consists of three major components,i.e.ROCOM Data Logger app,which utilizes a smart phone to collect acceleration data,ROCOM Risk Mapping app,which is a web-based application,and ROCOM Visual Tracking,which is a stand along software.ROCOM is able to detect adverse acceleration( >2g)or vibration on the road surface similar to the High Accuracy GPS Data Logging for Vehicle Testing(VBOX).Risk mapping validation along a section of the motorcycle lane along Federal Route 2 shows that not only ROCOM have the similar risk-mapping pattern,but its route tracking capability on the map is far superior that the VBOX.The pilot and field test results showed that ROCOM works best when mounting the smartphone on the motorcycle handle bar or basket,and it can detect various road anomalies with successful detection rate of 62%,with high detection rate when passing through uneven road surfaces.

A case study of environmental characteristics on urban road-surface and air temperatures during heat-wave days in Seoul

High road-surface temperature due to heat waves can lead to dangerous driving conditions such as tire blowouts and deformation induced by thermal stress on the roads. In this study, a Mobile Observation Vehicle dataset, with high spatial and temporal resolutions for the heat-wave episode that occurred on 16–17 August 2018, is used to understand environmental characteristics on urban road-surface and air temperatures in Seoul. This study demonstrates that the magnitude of urban road-surface temperature is dependent on the differences in incoming solar radiation due to screening of high-rise buildings in the Gangnam area, and is associated with the topographical features in the Gangbuk area. The road-surface temperature in the section of darker-colored asphalts was higher than that of lighter-colored asphalts, with a mean difference of 6.8°C, and both surface and air temperatures on the iron plate were highest, with means of 51.7°C and 35.1°C,respectively. In addition, during the water-sprinkling period, road-surface temperature was cooled by about 8.7°C(19%) compared with that in the period without water-sprinkling, but there was no significant change in air temperature. The current results could be practically used to improve roadsurface temperature prediction models for civil engineers or road managers.

Technologies for Asphalt Pavement Surface Testing in Road and Bridge Construction

Asphalt pavement is currently one of the main components in the construction of roads and bridges.However,from a practical point of view,various quality problems are prone to occur in the surface layer of asphalt pavement,which will lead to the poor overall quality of road and bridge projects.Therefore,it should be applied reasonably.Advanced testing technologies are used to test the mixture quality,compaction,segregation,thickness,and other aspects of the asphalt pavement surface layer,so as to improve the quality of the asphalt pavement surface layer,and then improve the overall quality of road and bridge construction.Therefore,this paper mainly analyzes the technologies for asphalt pavement surface layer testing in road and bridge engineering construction.

广西某高速公路沥青路面车辙病害影响因素分析

对实体依托工程的现场调研、室内试验和建立模型进行分析,从重载交通、路面结构、抗压强度、压实度等因素分析了对广西高速公路沥青路面车辙病害的影响,提出加强对重载、超载的管制,进行针对性路面结构设计,提高沥青路面施工质量稳定性的对策建议。

Use of generated artificial road profiles in road roughness evaluation

In the evaluation of road roughness and its effects on vehicles response in terms of ride quality, loads induced on pavement, drivers＇ comfort, etc., it is very common to generate road profles based on the equation provided by ISO 8608 standard, according to which it is possible to group road surface profiles into eight different classes. However, real profiles are significantly different from the artificial ones because of the non-stationary fea- ture of the first ones and the not full capability of the ISO 8608 equation to correctly describe the frequency content of real road profiles. In this paper, the international roughness index, the frequency-weighted vertical acceleration awz according to ISO 2631, and the dynamic load index are applied both on artificial and real profiles, highlighting the different results obtained. The analysis carried out in this work has highlighted some limitation of the ISO 8608 approach in the description of performance and conditions of real pavement profiles. Furthermore, the different sensitivity of the various indices to the fitted power spectral density parameters is shown, which should be taken into account when performing analysis using artificial profiles.

Road identification method based on angular acceleration of vehicle driving wheel

The fundamental principle of road identification by using angular acceleration of driving wheels was demonstrated in this paper. Based on the analysis of energy conversion and parameters variation during the vehicle drive slip process, the change of adhesion coefficient relative to the an- gular acceleration were theoretically studied experimentally validated. The variation shows that the change of adhesion coefficient relative to the angular acceleration and the change of slip ratio in the drive slip process have same trend-both of them exist an only optimal angular acceleration corre- sponding to the peak value of adhesion coefficient. The peak adhesion coefficient of the prototype vehicle is about 0. 14 on the ice-covered road surfaces, with the corresponding optimal angular accel- eration of about 23.5 rad/s2 and optimal slip ratio of about 9. 4%.

Sustainability of lime stabilized road subgrade in mountainous regions of Türkiye

In this paper the use of lime stabilized subgrade for low volume roads in two regions with high mountains and different frost penetration conditions in Türkiye was investigated in terms of design,performance,and cost.Pavements on unstabilized and stabilized subgrade were designed for two regions(Izmir and Van),covering all climate variations.The resilient modulus of the lime stabilized subgrade with different soil pulverization levels for non-freezing and freezing conditions were taken from a previous laboratory study.Frost effects were considered in pavement design using two different approaches,including limited subgrade frost penetration method and reduced subgrade strength method.Detailed application and evaluation were performed for all steps.Lime stabilized subgrades significantly reduced the thickness of base courses,and the benefit of lime stabilization was highly dependent on soil pulverization level.A detailed cost analysis on the unstabilized and stabilized cases found that the use of lime stabilization in the subgrade provided significant initial cost savings.Comparative analysis by using the AASHTO(1993)method and KENPAVE software,and quantity effect of soil pulverization level on the performance of low volume roads from a service life perspective,show that subgrade resilient modulus can be estimated.It is also possible to make correct performance estimation in the field.The results of the study show that lime stabilization is a good solution for low volume roads in the mountainous regions of Türkiye.

“Noisy”issues in road acoustics:A white paper

Despite almost a century of studies dealing with traffic noise,researchers and practitioners still face old and new issues when designing a low-noise pavement.Given that,this manuscript aims at focusing on a number of unsolved questions,namely theoretical or technological.1)Is it viable to balance diverse road-related needs(i.e.,noise,expected life,texture levels,and friction)?2)How much does the pavement material affect its acoustic performance(the remaining factors being constant)?3)How much reliable is the relationship between road texture and mixture aggregate gradation?Based on the analysis of these issues,it emerges that:1)optimal pavement design involves complex mix optimization and there are theoretical and practical bases to set up a balanced approach to address the complexity of pavement design;2)high percentages of crumb rubber could optimise road acoustic response but this latter has a relationship with the tyre/road noise(expressed,for example,in terms of close proximity index)that calls for further investigation;3)aggregate gradation appears to be a reliable basis to predict surface texture and therefore,under given boundary conditions,tyre/road noise;and 4)further studies and investigations are needed in terms of local calibration of deterioration curves and setting up of a sound method to assess the frequency response of asphalt concretes and to govern on-site noise indicators based on mixture properties.

Study on Test Methods for Mechanical Properties of Semi-rigid Base Cores of In-service Pavements

Compressive strength and compressive resilience modulus are two important parameters to measure the mechanical properties of semi-rigid base.The test methods of semi-rigid base cores are different from those of the laboratory samples in terms of sample acquisition,sample selection and humidity requirements.Core-drilling location,size of core sample,smoothness and humidity conditions were analyzed.The test methods of compressive strength and compressive resilience modulus were proposed.The research results show that compressive strength of lime fly-ash stabilized gravels base has a tendency of increasing during a long period.The compressive resilience modulus increases significantly with compressive strength of semi-rigid base.The compressive resilience modulus generally is 3-4 times than the recommended range of asphalt pavement design specifications.The fluctuation range of compressive resilience modulus is obviously higher than the compressive strength.The compressive resilience modulus is more sensitive to the construction variability.The overall trend between the compressive resilience modulus and the back-calculation modulus is consistent.FWD(falling weight deflectometer)back-calculation modulus can reflect the stiffness and bearing capacity of asphalt pavement.