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With the rapid promotion of autonomous driving technology, it is extremely important to scientifically anticipate the related technologies and analyze their possible impact on urban road systems. The accuracy of detection and localization of traffic elements of autonomous driving is closely related to the ability of autonomous driving devices to make control decisions and the safety of autonomous driving. The study designs a new high-speed road driving scheme based on autonomous driving by analyzing the challenges related to urban traffic that may be brought about by unmanned driving. On the basis of the faster R-CNN algorithm, the context information around the target is introduced to locate and detect small-scale traffic signs. A new pedestrian detection model is designed, which is based on the feature pyramid network and introduces the SE module to highlight the features of the visible part of the pedestrian and reduce the missed detection rate caused by inter-class occlusion. The improved traffic sign detection framework improves the detection accuracy by 18.91% compared to the original faster R-CNN, while the enhanced pedestrian inspection method improves the detection accuracy by 14.00%. For both traffic sign detection and pedestrian detection accuracy and speed are improved compared to the original method. [ABSTRACT FROM AUTHOR]

A roadway path is most commonly perceived as a 3-D element structure placed within its surrounding environment either within or outside urban areas. Design guidelines are usually strictly followed to ensure safe and comfort transportation of people and goods, but in full alignment with the terrain configuration and the available space, especially in urban and suburban areas. In the meantime, vehicles travelling along a roadway consume fuel and emit pollutants in a way that depends on both the driving attitude as well as the peculiar characteristics of road design and/or pavement surface condition. This study focuses on the environmental behavior of roadways in terms of fuel consumption, especially of heavy vehicles that mainly serve the purpose of freight transportation within urban areas. The impact of horizontal and vertical profiles of a roadway structure is theoretically considered through the parameters of speed and longitudinal slope, respectively. Based on theoretical calculations with an already developed model, it was found that the slope plays the most critical role, controlling the rate of fuel consumption increase, as an increase ratio of 2.5 was observed for a slope increase from 2% to 7%. The variation was less intense for a speed ranging from 25 to 45 km/h. The investigation additionally revealed useful discussion points for the need to consider the environmental impact of roadways during the operation phase for a more sustainable management of freight transportation procedures, thereby stimulating an ad hoc development of fuel consumption models based on actual measurements so that local conditions can be properly accounted for and used by road engineers and/or urban planners. [ABSTRACT FROM AUTHOR]

A roadway path is most commonly perceived as a 3-D element structure placed within its surrounding environment either within or outside urban areas. Design guidelines are usually strictly followed to ensure safe and comfort transportation of people and goods, but in full alignment with the terrain configuration and the available space, especially in urban and suburban areas. In the meantime, vehicles travelling along a roadway consume fuel and emit pollutants in a way that depends on both the driving attitude as well as the peculiar characteristics of road design and/or pavement surface condition. This study focuses on the environmental behavior of roadways in terms of fuel consumption, especially of heavy vehicles that mainly serve the purpose of freight transportation within urban areas. The impact of horizontal and vertical profiles of a roadway structure is theoretically considered through the parameters of speed and longitudinal slope, respectively. Based on theoretical calculations with an already developed model, it was found that the slope plays the most critical role, controlling the rate of fuel consumption increase, as an increase ratio of 2.5 was observed for a slope increase from 2% to 7%. The variation was less intense for a speed ranging from 25 to 45 km/h. The investigation additionally revealed useful discussion points for the need to consider the environmental impact of roadways during the operation phase for a more sustainable management of freight transportation procedures, thereby stimulating an ad hoc development of fuel consumption models based on actual measurements so that local conditions can be properly accounted for and used by road engineers and/or urban planners.

The introduction of connected automated vehicles (CAVs) on freeways raises significant challenges, particularly in interactions with human-driven vehicles, impacting traffic flow and safety. This study employs traffic microsimulation and surrogate safety assessment measures software to delve into CAV–human driver interactions, estimating potential conflicts. While previous research acknowledges that human drivers adjust their behavior when sharing the road with CAVs, the underlying reasons and the extent of associated risks are not fully understood yet. The study focuses on how CAV presence can diminish conflicts, employing surrogate safety measures and real-world mixed traffic data, and assesses the safety and performance of freeway interchange configurations in Italy and the US across diverse urban contexts. This research proposes tools for optimizing urban layouts to minimize conflicts in mixed traffic environments. Results reveal that adding auxiliary lanes enhances safety, particularly for CAVs and rear-end collisions. Along interchange ramps, an exclusive CAV stream performs similarly to human-driven ones in terms of longitudinal conflicts, but mixed traffic flows, consisting of both CAVs and human-driven vehicles, may result in more conflicts. Notably, when CAVs follow human-driven vehicles in near-identical conditions, more conflicts arise, emphasizing the complexity of CAV integration and the need for careful safety measures and roadway design considerations. [ABSTRACT FROM AUTHOR]

The introduction of connected automated vehicles (CAVs) on freeways raises significant challenges, particularly in interactions with human-driven vehicles, impacting traffic flow and safety. This study employs traffic microsimulation and surrogate safety assessment measures software to delve into CAV–human driver interactions, estimating potential conflicts. While previous research acknowledges that human drivers adjust their behavior when sharing the road with CAVs, the underlying reasons and the extent of associated risks are not fully understood yet. The study focuses on how CAV presence can diminish conflicts, employing surrogate safety measures and real-world mixed traffic data, and assesses the safety and performance of freeway interchange configurations in Italy and the US across diverse urban contexts. This research proposes tools for optimizing urban layouts to minimize conflicts in mixed traffic environments. Results reveal that adding auxiliary lanes enhances safety, particularly for CAVs and rear-end collisions. Along interchange ramps, an exclusive CAV stream performs similarly to human-driven ones in terms of longitudinal conflicts, but mixed traffic flows, consisting of both CAVs and human-driven vehicles, may result in more conflicts. Notably, when CAVs follow human-driven vehicles in near-identical conditions, more conflicts arise, emphasizing the complexity of CAV integration and the need for careful safety measures and roadway design considerations.

• We applied the ISO DRT to measure the cognitive load of driving four vehicles on two highways with distinct characteristics. • Worse DRT performance was found on the narrower, more winding highway. • Vehicle-specific differences were also found. • DRT performance in the Volvo was worse than that observed for the Tesla, Nissan, and Cadillac. The ISO Detection Response Task (DRT) is a standard tool for assessing drivers' cognitive load and it has primarily been used to measure the cognitive load of completing non-driving tasks and interacting with vehicle systems. In this study we use the DRT to measure the workload of driving four separate vehicles (a 2019 Tesla Model 3, a 2018 Cadillac CT6, a 2018 Volvo XC90, a 2019 Nissan Rogue) in manual mode and on two distinct roadways (US Interstate Highway 15 and 80) in and around Salt Lake City, UT. Results showed that the unique road characteristics of I-80 resulted in higher levels of cognitive load as demonstrated by the slower DRT response times. Likewise, different levels of workload were found across the four vehicles, with higher workload levels found for one of the four vehicles. This study expands the use of the DRT outside its original area of application, and advances it as a tool to assess the cognitive demand induced by varying road and vehicle characteristics. [ABSTRACT FROM AUTHOR]

City events take place in the Zhangzhou Olympic Sports Center, resulting in traffic. Hence, this study analyzed the road planning and design around Zhangzhou Olympic Sports Center through traffic demand forecasting. The simulated data and road plan underwent macro prediction model technology and numerical simulation technology through Emme and TransCAD. The regional road network structure, traffic demand forecast, plane, longitudinal section, and cross-sectional program selection were investigated to determine a reasonable design program. While urban development programs were implemented, the study ensured an increase in the city's economic growth alongside the guaranteed value of citizens' welfare. [ABSTRACT FROM AUTHOR]

• About a quarter of single-bicycle crash casualties ride off the pavement. • The wider the cycle track, the more distance cyclists maintain from the verge. • Cyclists ride closer to the verge due to oncoming cyclists. • A width of 250 cm is advised for bidirectional cycle paths. Introduction: Sufficient cycle track width is important to prevent single-bicycle crashes and collisions between cyclists. The assumptions on which the minimum width is based in guidelines is founded on only a few studies. The aim of the present study is to investigate the relationship between cycle track width and lateral position of cyclists. Method: We conducted an experiment to evaluate the lateral position of cyclists along cycle tracks with different widths (Study 1). Participants cycled on an instrumented bicycle with a LIDAR to measure their lateral position. Five conditions were defined: cycle track width of 100 cm, 150 cm and 200 cm without interaction, and cycle track width of 150 cm and 200 cm with an oncoming cyclist simulated by a parked bicycle. The cross-sectional Study 2 is based on the collected lateral position measurements at cycle tracks with varying width reported in Dutch studies since 2010. Results: The experimental Study 1 with 24 participants shows that an increase in cycle track width causes cyclists to ride further away from the verge and keep more distance from an oncoming cyclist. The cross-sectional Study 2 was based on lateral position measured at 33 real-life Dutch cycle tracks. Study 2 yielded similar results, indicating that doubling pavement width increases lateral position by some 50%. Study 2 shows that, compared with a solo cyclist without interaction, a right-hand cyclist of a duo and a cyclist meeting an oncoming cyclist ride around 30% closer to the verge. Conclusions: The wider the cycle track, the more distance cyclists maintain from the verge. Cyclists ride closer to the verge due to oncoming cyclists. Practical applications: Given a cyclists' lateral position while meeting, common variations between cyclists' steering behavior, and vehicle width and circumstances, a cycle track width of 250 cm is needed for safe meeting maneuvers. [ABSTRACT FROM AUTHOR]

The low-speed turning maneuverability of vehicles is closely related to a well-known offtracking phenomenon which occurs when the rear wheels of a turning vehicle deviate towards the inside of a horizontal curve. Although numerous mathematical models and computer programs for vehicle swept path analysis have been developed in the past, only a few of them can calculate the maximum transient offtracking of a turning vehicle, yet with limited accuracy. The authors were motivated by this fact to find a new mathematical solution for maximum transient offtracking calculation of a single-unit vehicle when negotiating circular curves. In the first stage, a transcendental equation defining vehicle maximum transient offtracking position is derived and numerically solved by Python 3.10.12. In the second stage, the polynomial regression model predicting accurate numerical solutions of the transcendental equation with the desired level of accuracy was developed and tested. The new calculation method is simple enough to simply take the vehicle datum length, circular curve radii, and turn angle, while instantly producing the maximum transient offtracking value, without the need to draw any of the vehicle movement trajectories.

When a road design solution is quite out of standards for the presence of insurmountable constraints, there is the need for an objective procedure aimed at achieving a certain level of safety for drivers. To avoid issues on judicial responsibility, designers aim to fully satisfy the existing standards, possibly without any exception. Traditional methodologies based on previous experience or road administrators' guidelines generally caused problems due to the high subjectivity involved in the analysis. In this paper, to overpass these issues, a rational procedure based on vehicles telemetry data in a simulated environment is proposed. This process, through synthetic indices, allows the analysts to compare two road geometries, similar but different, because one includes curves with shorter residual circular arcs than threshold values imposed by Italian standards. The main results, derived from a two-way ANOVA with subsequent contrast analysis, suggest that a certain deviation respect to the standards did not determine any decay in the driver's performance. Compared to the existing literature, in this study, a full objective procedure was proposed, based on a totally new indicator, which can be easily adapted to any context, involving driver, road and vehicle at the same time. [ABSTRACT FROM AUTHOR]

Roads are the primary transportation infrastructure of every country and play a crucial role in achieving sustainable economic development. Neglecting environmental considerations in civil engineering projects, especially in the design and construction of roads, can cause extensive damage to human societies and ecosystems. One of the most critical issues in road design is selecting an optimal alignment that minimizes changes to land use, preserves wetlands, forests, and agricultural land, and provides a platform for sustainable development. This decision has a significant impact on the execution, operation, and maintenance costs of the route, as well as its surrounding geography. This research examines the optimal horizontal alignment between two desired starting and ending points, taking into account environmental factors, construction cost parameters, and safety indices in the Anzali ringroad highway area. The route design data was collected and the important variables affecting the route design were determined. Then, the optimal balance was evaluated using the genetic algorithm method. After analyzing the generated data, we propose the optimal horizontal alignment as the final recommended option, with four horizontal arcs and a length of 14.991 kilometers. This alignment is compatible with the environment and has significantly lower greenhouse gas emissions, resulting in a cost savings of 3.7 million dollars compared to the initial alignment. It is a desirable and shorter horizontal alignment between two points in one of the important areas of the Ramsar International Convention (Anzali). [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Compared to traditional electronic maps, high-precision maps are more about providing services for vehicles. Because vehicles lack the visual recognition and logic inherent in humans, high-precision maps can assist vehicles in identifying obstacles, vehicles, etc., and can also expand their environmental awareness capabilities. This can provide vehicles with a global perspective that other sensors cannot obtain. This article includes road, traffic, and facility information outside the sensor monitoring range. This paper analyzes and defines road design data and high-precision map construction in detail, and then verifies the progressiveness of high-precision map construction methods based on road design data compared with traditional high-precision map construction methods through experimental analysis [ABSTRACT FROM AUTHOR]

In principle, nature reserves are managed and controlled according to the core area and the general control area. At present, there is no relevant design specification for the design system of patrol road in various protected areas. This paper analyzed the factors to be considered in determining the grade, horizontal and vertical design indicators, and cross section indicators of the patrol road in the protected area, and came up with the corresponding design indicators and parameters, so as to provide a certain reference for the subsequent patrol road design. [ABSTRACT FROM AUTHOR]

The construction and operation of linear infrastructure has major impacts on biodiversity through loss of habitat, increased mortality and loss of connectivity. In particular, minimising the impact of roads which pass through ecologically sensitive areas on surrounding species at the construction and operational phases is critical for conservation. However, potential impacts are rarely known perfectly at the construction phase and early in the operational phase. To address this problem, a company could build flexibility into road operation so that it can respond rapidly to future ecological impacts if necessary. In this paper we analyse the value of this flexibility using stochastic dynamic programming and use the results to guide a global search algorithm to find high value roads in the region. We consider flexibility in terms of the proportion of traffic volume routed along the road, with the remainder passing along an existing higher-cost, lower-impact road. We applied this to an example scenario where a road must be routed through a region with a vulnerable species present. By incorporating flexibility, the proposed model was able to find a road that met a desired ending population of animals and was more valuable than roads found under existing design alternatives. [ABSTRACT FROM AUTHOR]

This study provides a comprehensive approach to the management of uncontrolled accesses, namely, access points without traffic lights, stop signs, right-of-way, yield signs, or right-turn acceleration/deceleration lanes. These elements of the road network are often associated with several safety issues given the inadequate conditions and limitations regarding their location, design, and visibility. This paper provides new insights into the geometric and functional design of uncontrolled accesses and contributes to the area of safety management measures. The implementation of the approach to a selected case study allows for the description of the methodology and to find interesting results concerning the cause-effect relationship between geometry-related variables and accidental events. In particular, the study focuses attention on the key factors of the geometric and functional design of accesses: radius and width, with the aim of defining more adequate design criteria aimed at improving safety. Furthermore, several interesting considerations are drawn relating to the types of connection transition shapes, allowing the selection of the most dangerous type for the safety of drivers and pedestrians. The most important finding is the high risk correlated to an access point with no materialised elements guiding the entry manoeuvre. [ABSTRACT FROM AUTHOR]

Copyright of Guangdong Architecture Civil Engineering is the property of Guangdong Architecture Civil Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Road vertical alignment design is a multi-objective design problem that needs to consider multiple constraints. Intelligent design based on optimization algorithms cannot wholly solve problems, such as multi-objective, uncertainty, and constraint dynamics. The article proposes a model of dynamically transforming design constraints into feasible regions as the design develops, to provide decision information before design actions rather than performing constraint evaluation after the design that reduces the empirical estimation. The design actions are divided into new design actions and modifying design actions, and corresponding feasible regions derived from constraints of design specifications and control elevations are established, respectively. Geometrical equations and program algorithms of feasible regions are described in the graphic environment, which is applied to the vertical alignment design to improve the design efficiency and decision-making level.

Copyright of Guangdong Architecture Civil Engineering is the property of Guangdong Architecture Civil Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Guangdong Architecture Civil Engineering is the property of Guangdong Architecture Civil Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Guangdong Architecture Civil Engineering is the property of Guangdong Architecture Civil Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Organic soil is characterised by high compressibility and should be improved so that it can be used for construction. The use of every method of soil improvement requires knowledge of the compressibility parameters. One of these parameters is the constrained modulus. The constrained modulus can be determined using laboratory or in-situ tests. In this study, the constrained modulus of organic soil was determined using oedometer and piezocone tests (CPTU). The author analysed subsoil under an approximately 250 m section of a designed road in north-eastern Poland. The constrained modulus of organic soil sampled from four different depths was determined in oedometer tests. Piezocone tests were conducted at 18 points located every 15 m along the length of the section concerned. To determine the constrained modulus based on the cone resistance from CPTU tests, the knowledge of the α and αM coefficients is needed. For the tested soil, the optimal range of the α coefficient from 0.4 to 0.7 was determined. The αM coefficient ranged from 0.4 to 0.8. The value of the constrained modulus of organic soil obtained from the oedometer tests, depending on the effective stress, ranged from approximately 100 kPa to 400 kPa. The constrained modulus of the tested soil decreased with depth, which both research methods proved.

Featured Application: The study investigates the factors influencing the longitudinal driving distance during the lane-changing process to provide a theoretical basis for the set buffer zone length of future autonomous driving dedicated lanes. With the development of intelligent transportation, dedicated highway lanes for autonomous vehicles (AVs), necessary for ensuring their right of way, have emerged as critical issues in intelligent transportation research, which makes it necessary to set up specialized lane-changing buffer zones in the lane adjacent to the dedicated one. Restricted by the current situation of intelligent transportation systems, based on NGSIM data, this study filters out typical lane-changing description data featuring lane-changing behaviors and constructs a principal component analysis (PCA) model containing factors affecting the longitudinal driving distance during the whole lane-changing procedure. The validity of the model is evaluated with a significance test. Comparing the PCA model to a general linear regression model, suggestions on setting the length of lane-changing buffer zones are put forward. The length of the buffer zone mainly considers speed, acceleration, and the flow in the dedicated lane. In general, a shorter buffer zone length can be achieved by increasing the design speed of the buffer zone, raising the headway of AVs in the dedicated lane, reducing the acceleration rate of lane-changing vehicles, and reducing the time proportion of the lane change preparation stage, which occurs earlier in the procedure. [ABSTRACT FROM AUTHOR]

Walking is the most important mode of transport in the “Global South. ” Depending on the location, the mode accounts for between 33 and 90% of trips. Despite its importance and the notion that walking is available to all, there are vast parts of the population that cannot use the mode, as infrastructure is not conducive. The gender and ability neutral approach to infrastructure provision ignores the needs of up to 75% of inhabitants, leading to isolation and the inability to access services. This paper describes the results of a desktop study that uses various types of literature and secondary data sources to conduct a qualitative assessment of the inclusivity of non-motorized transport and vulnerable population groups (women, children, the elderly, and people with disabilities) in its planning and implementation approach, rather than actual implementations. Cape Town is used as a case study city. Results were verified by local experts. Gender neutral planning and roll out of infrastructure has been slow and there is no evidence at all that women, children, and the elderly are considered in the “Global South” context. Regarding people with disabilities, there has been some progress. Tactile paving and drop curbs are occasionally included. However, due to a lack of training of contractors and personnel that audits implementation projects, the quality of infrastructure for people with disabilities is poor. In the case of Cape Town, the qualitative scores are a mere two credits out of a maximum of 75 credits regarding the non-motorized transport, gender and social inclusion in transportation planning and practice. The authors suspect that scores in many African cities will be even lower. As with many other cities in the “Global South,” and more specifically in Africa, Cape Town needs to change its management structure, break down the silos between departments, embrace the input of representatives of vulnerable groups during infrastructure design and implementation and, more importantly, increase the budget for non-motorized transport. There is also a clear need for improved training for contractors and city infrastructure auditors, as implemented infrastructure is often substandard. The study resulted in the development of a hierarchical framework.

This paper presents a new algorithm to build feasible solutions to a MILP formulation of the vertical alignment problem in road design. This MILP involves a large number of special ordered set of type 2 variables used to describe piecewise linear functions. The principle of the algorithm is to successively solve LPs adapted from the MILP by replacing the special ordered set of type 2 constraints by linear constraints. Proof that the solutions to the successive linear relaxations of the MILP converge to a feasible solution to the MILP is provided. Numerical results emphasize that the algorithm performs better than CPLEX for large scale vertical alignment problems. [ABSTRACT FROM AUTHOR]

This study provides a comprehensive approach to the management of uncontrolled accesses, namely, access points without traffic lights, stop signs, right-of-way, yield signs, or right-turn acceleration/deceleration lanes. These elements of the road network are often associated with several safety issues given the inadequate conditions and limitations regarding their location, design, and visibility. This paper provides new insights into the geometric and functional design of uncontrolled accesses and contributes to the area of safety management measures. The implementation of the approach to a selected case study allows for the description of the methodology and to find interesting results concerning the cause-effect relationship between geometry-related variables and accidental events. In particular, the study focuses attention on the key factors of the geometric and functional design of accesses: radius and width, with the aim of defining more adequate design criteria aimed at improving safety. Furthermore, several interesting considerations are drawn relating to the types of connection transition shapes, allowing the selection of the most dangerous type for the safety of drivers and pedestrians. The most important finding is the high risk correlated to an access point with no materialised elements guiding the entry manoeuvre.

Because of the singular form and low flexibility of the clothoid as a highway transition curve in highway horizontal alignment, the K-curve, whose ratio of the chord-tangent angle to the tangential angle at any point is fixed, was proposed in a previous work, including the corresponding parametric equations and basic characteristics, and its high flexibility and various shapes were proved. Here, the application and verification of the K-curve in highway alignment is further studied. The solution methods of the K-curve for different connections are given. Through theoretical calculations and specific real-world examples, the geometric positions and lateral forces of the K-curve and the clothoid under different connection conditions are compared. The results show that the difference between the K-curve and clothoid in the above two aspects under a straight line-to-circle connection is greater than that under a circle-to-circle connection as an egg curve, and although the lateral force coefficient of the K-curve is smaller than that of the clothoid, the K-curve suffers from rapid change in the lateral force coefficient and a higher lateral acceleration change rate. Finally, the application conditions of the K-curve for highway alignment design are given with consideration of the centrifugal acceleration change rate. [ABSTRACT FROM AUTHOR]

This paper presents a new approach to the design methodology of road routes, in literature often referred to as the polynomial alignment. The author proposes the use of the so-called general transition curves that have been described in detail in his earlier research papers. General transition curves employ only one curvature extremum, and the whole curved transition between two extreme points of zero curvature value is described by a single equation. As a result, the curves are very useful for the creation of route geometry in accordance with the principles of polynomial alignment. The paper describes the main concept of polynomial alignment and presents equations of curves which can be used in the proposed alignment procedure. In addition, the paper gives a detailed description of design procedures. [ABSTRACT FROM AUTHOR]

Bridge inspections are a vital part of bridge maintenance and the main information source for Bridge Management Systems is used in decision-making regarding repairs. Without a doubt, both can benefit from the implementation of the Building Information Modelling philosophy. To fully harness the BIM potential in this area, we have to develop tools that will provide inspection accurate information easily and fast. In this paper, we present an example of how such a tool can utilise tablets coupled with the latest generation RGB-D cameras for data acquisition; how these data can be processed to extract the defect surface area and create a 3D representation, and finally embed this information into the BIM model. Additionally, the study of depth sensor accuracy is presented along with surface area accuracy tests and an exemplary inspection of a bridge pillar column. [ABSTRACT FROM AUTHOR]

With the development of intelligent transportation, dedicated highway lanes for autonomous vehicles (AVs), necessary for ensuring their right of way, have emerged as critical issues in intelligent transportation research, which makes it necessary to set up specialized lane-changing buffer zones in the lane adjacent to the dedicated one. Restricted by the current situation of intelligent transportation systems, based on NGSIM data, this study filters out typical lane-changing description data featuring lane-changing behaviors and constructs a principal component analysis (PCA) model containing factors affecting the longitudinal driving distance during the whole lane-changing procedure. The validity of the model is evaluated with a significance test. Comparing the PCA model to a general linear regression model, suggestions on setting the length of lane-changing buffer zones are put forward. The length of the buffer zone mainly considers speed, acceleration, and the flow in the dedicated lane. In general, a shorter buffer zone length can be achieved by increasing the design speed of the buffer zone, raising the headway of AVs in the dedicated lane, reducing the acceleration rate of lane-changing vehicles, and reducing the time proportion of the lane change preparation stage, which occurs earlier in the procedure.

• Time headway is significantly different from various designs of dedicated lanes. • A significant lower time headway was observed on the continuous access lane. • The average time headway of males is distinctly lower than females. • Time headway is significantly negatively correlated with the years of driving. Automated vehicles (AVs) are expected to improve traffic flow efficiency and safety. The deployment of AVs on motorways is expected to be the first step in their implementation. One of the main concerns is how human drivers will interact with AVs. Dedicating specific lanes to AVs have been suggested as a possible solution. However, there is still a lack of evidence-based research on the consequence of dedicated lanes for AVs on human drivers' behavior. To bridge this research gap, a driving simulator experiment was conducted to investigate the behavior of human drivers exposed to different road design configurations of dedicated lanes on motorways. The experiment sample consisted of 34 (13 female) licensed drivers in the age range of 20–30. A repeated measures ANOVA was applied, which revealed that the type of separation between the dedicated lane and the other lanes has a significant influence on the behavior of human drivers driving in the proximity of AV platoons. Human drivers maintained a significantly lower time headway (THW) when driving in the proximity of a continuous access dedicated lane as compared to a limited-access dedicated lane with a guardrail separation for AV platoons. A similar result was found for the limited-access dedicated lane in comparison to the limited-access dedicated lane with guardrail separation. Moreover, the results regarding the empirical relationships between THW and sociodemographic variables indicate a significant THW difference between males and females as well as a significant inverse relationship between THW and the years of driving experience. [ABSTRACT FROM AUTHOR]

This study investigated the nature and causes of unsafe driving behavior at roundabouts through an on-road study. Four urban double-lane roundabouts with different layouts were selected for an on-road study. Sixty-six drivers (41 males and 25 females) aged 18-65 years took part in the study. Unsafe behaviors observed during the in situ survey were divided into three different categories: entry unsafe behaviors, circulation unsafe behaviors, and exit unsafe behaviors. Three chi-square automatic interaction detection (CHAID) analyses were developed in order to analyze the influence of roundabout characteristics and maneuvers on unsafe behaviors at double-lane roundabouts. The results confirmed the awareness that double-lane roundabouts are unsafe and inadvisable. More than half of unsafe driving behaviors were found to be entry unsafe behaviors. Moreover, the entry radius was found to be the geometric variable most influencing unsafe driving behaviors. [ABSTRACT FROM AUTHOR]

The stability of slopes and embankments under the influence of static and seismic loads has been the subject of study for many researchers. This paper stands for an attempt to present tolerable move-ments, based on caused damage on slopes of the embankments, as well as to connect them with natural disas-ters of the environment.

Improving road safety is not only reliant on engineering aspects but also on the surrounding landscape, which plays an indispensable role in drivers’ visual perception. As a part of road landscapes, green areas affect road safety by screening or framing views. While vistas could be highlighted in safe spots in order for road users to enjoy their travel, in dangerous scenic points, visual attractions need to be concealed to lessen visual distractions and the risk of accidents. This study aims at optimizing road safety through sustainable landscape design in one of the dangerous Tehran–Dizin road bends to meet both road safety and environmental requirements. In doing so, cone of vision formulas have been applied to calculate measures of green landscape features so as to hide visual distractions and upgrade safety. To design such a green landscape, green resources and their characteristics have been elaborated, and native species have been suggested in plant composition, which can improve the sense of place, enhance the environment, and create a sustainable landscape. The research shows that a cone of vision could functionally be employed to increase the success of a designed green landscape, especially in situations where two-dimensional approaches are not sufficient.

Multi-fidelity algorithms for solving the horizontal alignment problem in road design are considered. A multi-fidelity surrogate model is built and quantile regression is used to understand its accuracy at various fidelity levels. Two algorithms are compared: a generalized pattern search algorithm with adaptive precision control, and a trust-region algorithm for unconstrained problems with controlled error. To make a fair comparison, the parameters of each algorithm are tuned on five small roads using performance profiles. Then the algorithms are evaluated on 35 roads, ranging from small to very large roads. The results show that using multi-fidelity surrogates in optimization algorithms provide notable speed-up when compared to single-fidelity algorithms while preserving the quality of solutions (cost error < 1 %). On the longest roads, higher speed-up and better accuracy are observed. [ABSTRACT FROM AUTHOR]