Road Cross Section Research Articles

Water repellency of soils on unpaved roads in coniferous forests

Forest roads play a crucial role in commercial forestry. Most of them are unpaved and exposed to increased surface runoff and the occurrence of soil erosion. Therefore, these roads constantly require repairs and maintenance, which are associated with the high cost of earthworks. Soil water repellency causes retardation of water infiltration into soil, which affects the generation of surface runoff, leading to the destruction of the active road layer. This phenomenon is well recognized in forest habitat soils, but poorly investigated in terms of soils constituting roads and communication routes. Therefore, the aims of this research were to determine the severity and persistence of potential water repellency in the case of soil collected from two unpaved roads in coniferous forest and to investigate the dependence between the severity of soil water repellency and its persistence. Soil samples (Dystric Brunic Arenosols) were collected from three points of the roadway, i.e., centre line, rut and roadside, from two different sites located in fresh coniferous and fresh mixed coniferous forest (Poland). The severity of soil water repellency was assessed, based on measured values of the wetting contact angle (Wilhelmy plate method) and the critical and 90° surface tensions. For this purpose, contact angle measurements of the solid phase, wetted by water–ethanol mixtures, were used and data results were analysed using the Zisman approach. The persistence of potential soil water repellency was assessed using the water drop penetration time test. The severity and persistence of soil water repellency depend on the forest habitat type surrounding the road and point locations on the road cross section. The soil samples collected from the roadside were more water repellent than samples taken from the centre line or rut. A strong relationship was found between the water drop penetration time and the advancing contact angle, the critical surface tension and the 90° surface tension.

Research on Intersection Frequent Overflow Control Strategy Based on Wide-Area Radar Data

Overflow identification and control at urban road intersection is a derivative problem of oversaturation control. The existing cross-section detector uses the road cross-section occupation of vehicles to identify the overflow state; then, the downstream road condition is often ignored. At present, more and more advanced traffic detection technologies, such as vehicle-to-infrastructure and wide-area radar, can provide reliable data for accurate overflow identification. In this paper, a new method of overflow identification and control at intersections is proposed by using advanced wide-area radar detection data. As a detector for specific segment of road, the wide-area radar can detect the traffic flow data in a certain range of road and provide more data types. Therefore, the average speed and space occupancy of the effective detection road segment are selected as subindicators to establish the comprehensive identification index of overflow identification. Then, the overflow control strategy is developed considering the traffic demand of the overflow phase and the nonoverflow phase. It is proved that the method is more accurate and effective in overflow identification and control by using simulation experiment of field data.

KELIO SKERSINIO PROFILIO PARINKIMO PAGAL PROJEKTINĮ VIDUTINĮ PAROS EISMO INTENSYVUMĄ IR SUDĖTĮ METODIKOS ANALIZĖ / ANALYSIS OF ROAD CROSS-SECTION DESIGNING CONSIDERING DESIGNED TRAFFIC VOLUME

Road design elements are being discussed in society. Traffic congestion is a reason why sometimes new road elements is not working. Roads are designed by their function in the world. It is known that the roads are classified according to their functional purpose. Functional purpose is a criteria, which determines road design class and road category. Normative documents in analyzed countries define analysis of road capacity and road level of service. This analysis must be done in road design process. Methodology of road cross-section designing rewied in this arcticle.

Car Speed Distribution in Front of a Stop-Line of Urban Regulated Intersection

Problem. Car speed is a very important indicator of the traffic organization level in conditions of the formed street-road network. The car speed in a particular place and at a specific time is definitely random, and therefore should be described by the distribution law. The generally well-known normal distribution of the car speed in free traffic conditions is transformed into another distribution when these conditions complicate. The strictest conditions are those where the car is forced to stop completely and stand for some time in anticipation of permission for further movement. One such case is regulated intersections, and therefore the establishment of a car speed distribution in these conditions is an urgent task for which a new concept of a car speed should be introduced. Goal. The goal is testing the hypothesis about the possibility of describing the car speed fluctuations in front of the stop-line of a regulated intersection by an exponential distribution law. Methodology. Development of the method for the car speed measuring in front of the stop-line of the city regulated intersection on the basis of understanding the speed as the average speed of a car passing distance through the road cross-section. Results. The results of observing the actual speed at a regulated intersection lead to the conclusion that a regulated intersection can significantly complicate the traffic conditions in comparison with the narrow passageway and this is reflected in the decrease of the average speed of vehicles and the growth of its standard deviation, that brings the gamma-distribution close to the exponential form. Originality. A new method of a car speed estimating was proposed, on the basis of which the method was developed and the hypothesis was tested regarding the indicator distribution of the car speed in front of the stop-line of the regulated intersection. Practical value. The obtained result allows to increase accuracy of the car speed prediction in analytical and simulation models of transport network functioning.

Road Network Connectivity Quality Assesment for Timor Leste National Road Network

Timor Leste is a very young country. Road network is still pretty the only blood vessel of the economy. Road network need to be well managed following the principle of Infrastructure Asset Management. Thus, the national road network still has to be evaluated against the primary network quality: the connectivity. Assessment indicated that all national center activities are connected by national road network. But, the connectivity cannot be said to be good enough for certains. Due to the mountainous and hilly area, the roads still need to be improved in term of road cross section and road geometry.

Rill and gully erosion on unpaved roads under heavy rainfall in agricultural watersheds on China’s Loess Plateau

Soil erosion causes agricultural land degradation. As one of the indispensable components of the agricultural system, unpaved roads are significant sediment sources, but road erosion is often overlooked because of the relatively small areas that roads cover. This study aims to investigate the severity of road erosion under extreme rainfall and ascertain the dominating factor. We investigated road erosion in two small watersheds after a heavy rainstorm to measure rill and gully erosion on three types of road in the field and determine the factors affecting that erosion with remote sensing images and geographic information system (GIS). Using Google images before the storm and unmanned aerial vehicle (UAV) images after the storm, we interpreted land use and measured geomorphological and vegetation factors. In 579 road cross-sections within 63 road erosion segments found along the 10.42 km roads surveyed, the average soil loss was 804.77 t ha^-1 from main unpaved roads, 471.78 t ha^-1 from secondary unpaved roads, and 147.46 t ha^-1 from trails. Gully erosion predominated over rill erosion on all three types of road. The average rill erosion was 0.41, 0.17, and 0.02 cm, compared with 4.88, 3.15, and 1.05 cm of gully erosion on the main unpaved roads, secondary unpaved roads, and trails, respectively. The contributing area dominated over other factors associated with road erosion under heavy rainfall and could explain 84.9% of the erosion from the road segment to which it drains based on the linear regression analysis. Furthermore, a nonlinear regression model with the contributing area and road segment gradient as predictors precisely predicted road erosion (coefficient of determination, 0.970).

Variation of traffic flow due to accumulated snow formation on road

Sapporo City has one of the heaviest snowfalls worldwide, and the road conditions in winter are getting remarkably worse. Snow removal works in winter are indispensable in order to secure traffic functions in the city. Snow accumulates on roads as soon as it is removed. It is also a problem that the deposited snow protrudes into the lanes of roads and the traffic flow drops. This study analyzed the size of deposited snow formation and the variation of traffic flow. We set up a camera for a four-lane road managed by Sapporo City (two lanes per side) and observed two seasons continuously. Width of deposited snow and traffic performance (Traffic Volume - Velocity) were analyzed based on the acquired images. The width of deposited snow was from 1.0 m to 2.5 m. When the width of the deposited snow exceeded approx.1.5 m, it was indicated that only one lane of the road will be in operation if it is originally operated as two lanes per side, with about 70% of the traffic volume and about 80% of the speed. In addition, based on the actual situation of use of bicycles and pedestrians in autumn, we propose redistribution of road cross-sections considering snow coverage width.

A Fully Automated Approach to Extract and Assess Road Cross Sections From Mobile LiDAR Data

Road cross sections are designed to ensure safe operation of highways. Tangent segments are typically designed with cross slopes to ensure efficient drainage of water off the road’s surface, likewise, on horizontal curves the cross section is superelevated (tilted) to help vehicles counteract centrifugal forces. In both cases, ineffective slopes that do not meet design requirements, put vehicles at risk of overturning and skidding. Similarly, if deficiencies exist in side slopes, the chance of recovery for vehicles that run-of-the-road decreases substantially. Thus, transportation agencies must constantly assess elements of a road’s cross section to ensure that they meet current design standards throughout their service life. The microscopic nature of cross sectional elements makes measuring such information time consuming, highly disruptive to traffic, and resource intensive. To facilitate more efficient assessments of such features, this paper proposes a novel algorithm to extract road cross sections from light detection and ranging data. The algorithm involves estimating vectors which intersect the road’s axis, whereby points within proximity to the vectors are retained and extracted. Slope information is then measured off the retained points. The proposed algorithm is fully automated and employs multivariate adaptive regression splines to identify locations of change in slope. The algorithm was tested on two highway segments in Alberta. The high efficiency and precise manner in which the slope data was extracted, demonstrates the value of using the proposed algorithm in performing network-level assessment of road cross sections.

The Calculation Method for Backfill Volume of Road Collapse in Mining Subsidence Based on GIS

There has been a significant development in the evaluation of methods to predict ground movement due to underground extraction based on geographical information systems (GIS). In order to make the calculation of the backfill volume of road collapse more convenient, the calculating methods of backfill volumes of straight road collapse and bent road collapse due to mining subsidence are derived based on GIS in this paper. To ensure the calculation accuracy of backfill volume, the interpolation method is used for the calculation of backfill volumes of road collapse in mining subsidence. Calculation procedure: Firstly, the area of arbitrary cross-section of road is calculated by geometric method. Further, the backfill volume of road collapse between the two adjacent cross-sections is the product of the area of cross- section and the calculating step. The total backfill volume of road collapse is calculated by the sum of the backfill volume of road collapse between multiple adjacent cross-sections. Then, the calculating methods are embedded in the GIS platform for calculation. The backfill volume of the railway collapse after the 1–12# mining face is 58,113.25 m3.

THE ANALYSIS OF METHODS OF RECEPTION OF LONGITUDINAL PROFILE OF ROADS

The analysis of methods of reception of longitudinal biases/profile of road important for carrying out of modelling of movement of the vehicle on the basis of geodetic charts, gaugings of roads by means of the geodetic equipment, use mobile laboratories is carried out, radar scanning of the earth, data read-out from the electronic control package of the car and the estimation of their accuracy is given. It is noticed that the listed modes are labour-consuming and Expenses and not always provide necessary accuracy. So in case of use of the popular data of radar scanning of the earth from companions the error can reach 30–50%. Though in the future in process of perfection of accuracy of sounding and availability of the information the given mode is represented to the most perspective.The method of registration of cross-sections/biases of the big sites of roads in the course of movement of the vehicle on the basis of microcontroller Arduino Due, the gauge of speedups and discharge angles MPU-6050 and data recording on a SD- card is offered, application of the combined processing of the information on the basis of the developed programs in language With in the microcontroller and in module S-Function Builder in package Matlab/Simulink is considered.By means of the offered methods registration of biases of road of difficult character by extent of 10 km is spent. And for the same road the method of use of a chart of radar scanning of the earth constructs a road cross-section. Comparison of results of methods of use of speedups and radar scanning of the earth is spent.Good coincidence of character of change of a cross-section of road and sredne-quadratic and maximum values of heights of a cross-section of the road, received on the offered methods (a toe-out of 7–20%) is revealed.

UAV를 활용한 효율적인 도로 급사면 단면추출

UAV를 활용한 효율적인 도로 급사면 단면추출

Evaluation of the environmental and human health impact of road construction activities

This work presents the results of the Life Cycle Assessment (LCA) of two different types of road cross-sections (i.e. embankment and trench sections) with the objective of calculating and analysing the environmental and human health impact related to their construction processes. The geometrical and technical characteristics of the examined sections comply with current Italian standards for minor highways. After analysing a base case scenario, the study evaluated the influence of several transportation conditions on the LCA of both cross-sections, including varying distances between quarries, landfills, mix plants and construction sites, and two European motorization types of road vehicles and earthmoving machines. In all cases, the LCAs included eight impact categories that were evaluated according to the European standard EN 15804. The results support the fact that several impact categories should be included as part of LCA studies if there is an interest for effectively mitigating the deleterious effects related to road construction. Indeed, the analyses show that the use of low impact procedures in the mix plants (e.g. reduction in mixing temperatures, increase of energy recycling), the renewing of the vehicle fleet, and the use of secondary raw materials provide better overall environmental results, not only in terms of greenhouse gas emissions but in all the impact categories considered.

Effect of the Road Environment on Road Safety in Poland

Run-off-road accidents tend to be very severe because when a vehicle leaves the road, it will often crash into a solid obstacle (tree, pole, supports, front wall of a culvert, barrier). A statistical analysis of the data shows that Poland’s main roadside hazard is trees and the severity of vehicles striking a tree in a run-off-road crash. The risks are particularly high in north-west Poland with many of the roads lined up with trees. Because of the existing rural road cross-sections, i.e. having trees directly on road edge followed immediately by drainage ditches, vulnerable road users are prevented from using shoulders and made to use the roadway. With no legal definition of the road safety zone in Polish regulations, attempts to remove roadside trees lead to major conflicts with environmental stakeholders. This is why a compromise should be sought between the safety of road users and protection of the natural environment and the aesthetics of the road experience. Rather than just cut the trees, other road safety measures should be used where possible to treat the hazardous spots by securing trees and obstacles and through speed management. Accidents that are directly related to the road environment fall into the following categories: hitting a tree, hitting a barrier, hitting a utility pole or sign, vehicle rollover on the shoulder, vehicle rollover on slopes or in ditch. The main consequence of a roadside hazard is not the likelihood of an accident itself but of its severity. Poland’s roadside accident severity is primarily the result of poor design or operation of road infrastructure. This comes as a consequence of a lack of regulations or poorly defined regulations and failure to comply with road safety standards. The new analytical model was designed as a combination of the different factors and one that will serve as a comprehensive model. It was assumed that it will describe the effect of the roadside on the number of accidents and their consequences. The design of the model was based on recommendations from analysing other models. The assumptions were the following: the model will be used to calculate risk factors and accident severity, the indicators will depend on number of vehicle kilometres travelled or traffic volumes, analyses will be based on accident data: striking a tree, hitting a barrier, hitting a utility pole or sign. Additional data will include roadside information and casualty density measures will be used – killed and injured.

Analysis of Road Cross Section Component Affecting Traffic Accident Severity on National Highway

Analysis of Road Cross Section Component Affecting Traffic Accident Severity on National Highway

Integrated signal optimization and non-traditional lane assignment for urban freeway off-ramp congestion mitigation

Exiting flow from urban freeway off-ramps coupled with limited capacity and traffic weaving at the downstream intersections creates major bottlenecks in urban road network. This paper presents an integrated design model for non-traditional lane assignment and signal optimization at the off-ramp, its downstream intersection, and their connecting segment with the objective to mitigate or eliminate traffic weaving and to maximize the section’s overall capacity. A mixed-integer non-linear program model is formulated to capture real-world operational constraints regarding the non-traditional lane assignment, special phasing treatment and signal timing. The mathematical model is linearized and solved by the standard branch-and-bound technique. Extensive numerical analysis and case study results validate the effectiveness of the proposed integrated model and demonstrate its promising application at locations where the upstream freeway off-ramp is located at the middle of the road cross section and the space between the stop line and off-ramp is limited.

Methodology for determining traffic volume for the analysis of roads efficiency

The present paper outlines the results of analyses of two hundred highest hourly volumes in a year, used for determining designed hourly volumes DHV to test road efficiency. Basing on them, three equations of the power function were elaborated. They enabled the assessment of traffic volume corresponding to a randomly chosen peak-hour in a year, depending on the value of annual average daily traffic AADT (below or above 25000 V/d), the share of heavy vehicles (below or above 30%), and the type of cross-section (1x2 or 1x4/2x2). In case of two-lane roads (1x2) the variation of direction distribution and per weekday with the highest hourly volumes in a year were analysed. As a result, it allowed for working out the methodology of estimating design hourly volume DHV, including a transition from values determined for road cross-section to individual road traffic directions. Finally, a calculation example, illustrating a practical method for making good use of obtained test results, was presented.

Evaluating the effects of physiographic parameters on the road cross section in mountain forests (Case study: northern forests of Iran)

Road cross section, as one the main effective factors in relation to fill and cut volume, was effective in costs and disturbance of forest road constructions. In this research, the effect of a few physiographic parameters on forest road cross section was evaluated. For this purpose, 192 cross sections on forest roads were delineated selectively in mountain forests in the north of Iran. The physiographic factors including elevation, hillside slope, slope aspect, rock base, and soil texture as well as cross section width were measured. After evaluating the data in terms of normality and homogeneity, it was analysed by Spearman's and Pearson's correlation tests using SPSS20. One-way ANOVA, two-way ANOVA, and Duncan grouping tests were used to determine the effect of the above-mentioned factors both separately and simultaneously. Results showed that the parameters including hillside slope, rock base, and soil texture had a significant effect. Elevation was recognized as a regional parameter due to the lack of any relationship with cross section. There was no significant relation between slope aspect and cross section. The hillside slope was defined as the most effective parameter on the cross section.

交通事故对路段通行能力影响作用分析

本文针对交通事故占用的不同车道，从道路横截面的车流量、车辆排队长度研究交通事故对城市道路通行能力的影响。通过从视频中截取事故道路横断面的车流量、路段上游车流量、路段车辆排队长度等数据，分析交通事故持续期间路段通行能力的变化过程，并分析当事故占用不同车道时，通行能力变化的差异及原因。 The effects of traffic accident on road traffic capacity have been researched from some aspects in-cluding different lanes occupied, traffic flow of the road cross section and the length of vehicle queue. Some data after traffic accident has happened, such as the traffic flow from the upper section of accidence, have been collected to analyze the variation process of road capacity. Moreover, the difference and reasons of road capacity varying have been further studied when the different lanes have been occupied in the process of accident treatment.

Operational Performance of Two-Way Left-Turn Lanes: Driving Simulator Evaluation

This study evaluated the operational performance of two-way left-turn lanes (TWLTLs) of varying widths in urban and suburban settings, in support of more flexible lane width standards for the South Carolina Highway Design Manual (SCHDM) update. Currently, the SCHDM only allows a TWLTL width of 15 ft to be used in design, and the distribution of TWLTL widths observed in a field study were justly limited; this limitation disallowed a proper evaluation of operational effects of TWLTL width. A fully integrated, high-fidelity driving simulator was used to test the operational effects of a range of TWLTL widths. Sixty participants made a series of left turns from a development driveway into TWLTLs of various widths. The TWLTL simulator scenarios included three-lane and five-lane road cross-section configurations and TWLTL widths of 12, 14, and 16 ft. Analyses were performed to determine the effects of ( a) TWLTL width on driver gap acceptance and ( b) turning-vehicle encroachments into through lanes. Analysis of variance tests indicated that TWLTL widths of 12, 14, and 16 ft had no effect on gap acceptance for three-lane and five-lane roadway sections. Trajectories were compared for a random sample of participants to evaluate the effect of TWLTL widths on vehicle encroachments into through lanes. On the basis of a subset of 30 participants, only one encroachment was observed for the scenario with a width of 12 ft, and two encroachments for the scenarios with widths of 14 and 16 ft. Greater variation in lane position was observed for wider TWLTLs, as participants took advantage of the larger space for maneuvering.

Characteristics of the Road and Surrounding Environment in Metropolitan Shopping Strips: Association with the Frequency and Severity of Single-Vehicle Crashes

Objectives: Modeling crash risk in urban areas is more complicated than in rural areas due to the complexity of the environment and the difficulty obtaining data to fully characterize the road and surrounding environment. Knowledge of factors that impact crash risk and severity in urban areas can be used for countermeasure development and the design of risk assessment tools for practitioners. This research aimed to identify the characteristics of the road and roadside, surrounding environment, and sociodemographic factors associated with single-vehicle crash (SVC) frequency and severity in complex urban environments, namely, strip shopping center road segments.Methods: A comprehensive evidence-based list of data required for measuring the influence of the road, roadside, and other factors on crash risk was developed. The data included a broader range of factors than those traditionally considered in accident prediction models. One hundred and forty-two strip shopping segments located on arterial roads in metropolitan Melbourne, Australia, were identified. Police-reported casualty data were used to determine how many SVC occurred on the segments between 2005 and 2009. Data describing segment characteristics were collected from a diverse range of sources; for example, administrative government databases (traffic volume, speed limit, pavement condition, sociodemographic data, liquor licensing), detailed maps, on-line image sources, and digital images of arterial roads collected for the Victorian state road authority. Regression models for count data were used to identify factors associated with SVC frequency. Logistic regression was used to determine factors associated with serious and fatal outcomes.Results: One hundred and seventy SVC occurred on the 142 selected road segments during the 5-year study period. A range of factors including traffic exposure, road cross section (curves, presence of median), road type, requirement for sharing the road with other vehicle types (trams and bicycles), roadside poles, and local amenities were associated with SVC frequency. A different set of risk factors was associated with the odds of a crash leading to a severe outcome: segment length, road cross section (curves, carriageway width), pavement condition, local amenities and vehicle, and driver factors. The presence of curves was the only factor associated with both SVC frequency and severity.Conclusions: A range of risk factors were associated with SVC frequency and severity in complex urban areas (metropolitan shopping strips), including traditionally studied characteristics such as traffic density and road design but also less commonly studied characteristics such as local amenities. Future behavioral research is needed to further investigate how and why these factors change the risk and severity of crashes before effective countermeasures can be developed.