Two-lane Roads Research Articles

A REVIEW OF FACTORS ASSOCIATED WITH DRIVING UNDER THE INFLUENCE OF ALCOHOL

Research into factors related to drink-driving is one of the challenges the researchers face in their scientific work. Creating conditions that would serve for prediction of driving under the influence of alcohol (DUI) is one of the goals of such research studies. A meta-analysis of DUI-related factors has been performed in this study. The first stage of the analysis includes the search of the ScienceDirect database. Two phrases have been used for the search: "alcohol and crash" and "DUI and crash". The research from the mentioned journal that is included in the meta-analysis, had to satisfy the condition in which the association between one of the factors and driving under the influence has been presented. The following are the three ways in which DUI has been defined: 1) self-reported behaviour, 2) testing performed by police officers, and 3) involvement in a road accident while being under the influence of alcohol. The second stage has seen the creation of a database of the strength of association between one of the factors and DUI, taken from selected papers in the database. All the factors that could be related to alcohol have been observed and included the following: driving style, characteristics of the driver, time and place of driving, characteristics of the vehicle, etc. Following the search of more than 1,000 studies in this field, an odds ratio has been created to associate the factors with DUI. The odds ratio of association (OR) represents the strength of association between a particular factor and DUI. By applying the mentioned methodology, a conclusion on the association between the factors and DUI has been drawn and may be used for prediction and as a typical example of DUI drivers in road traffic. When it comes to driver behaviour, the most important predictors of DUI are excessive speed, driving at night-time, failing to wear a seat belt, previous DUI experience, the presence of passengers in a car. As for the location, the greatest odds ratio associated with a DUI driver concerns driving an older car on a two-lane road in the urban area. The results of this study can be used for further development of the legislation related to drink-driving and consequently for improvement of the road safety situation in a territory.

A speed limit advisory system provided by in-vehicle HMI considering auditory perception characteristics for connected environment

In-vehicle HMI (Human Machine Interface) systems are well studied due to their great application prospect, but the recent development of connected technologies raises more possibilities that this technology provides more accurate speed limit warnings to ensure driver safety according to specific vehicle and road parameters. To capitalize on the potential of in-vehicle HMI systems to provide auditory and visual warnings to drivers and to improve adoption and utilization of this warning information. To this end, we designed a speed limit advisory system (SLAS) that recommended reduced speeds for hazardous sections of road, communicated to drivers by their in-vehicle HMI systems. Frontal distance models of single and gradient auditory warning were implanted into the systems to determine the warning timing. We then tested these SLASs in a high-fidelity simulator in order to evaluate their utility. 70 participants (mean age = 28.7 years; 36 male) drove through a simulated 15 km stretch of one-way two-lane rural road. We evaluated five different warning modes: single visual (SV), single audio visual (SAV), gradient visual (GV), gradient audio visual (GAV) or control (roadside sign). Participants using the SLAS slowed down significantly compared to the control group before entering the curve, with drivers receiving GAV warnings driving lowest speeds. Less experienced drivers exhibited higher compliance with GAMs (GV or GAV). The SLAS was generally considered useful though not by drivers with>10 years of driving experience. Drivers tended to prefer singular warnings to gradated warnings, which were rated as equally preferable to roadside signage. Eye tracking data indicated that none of the SLAS modes were overly distracting to the drivers. Overall, we find that the SLAS improves driver safety while producing no obvious distraction. The main difficulty lies in persuading experienced drivers to use the system. In a word, the results of this study provide validation for the concept of HMI warning system using connected technology in hazardous road areas and help determine the appropriate timing of in-vehicle warnings.

EVALUATION OF TWO-LANE ROAD SECTIONS IN TERMS OF TRAFFIC RISK USING AN INTEGRATED MCDM MODEL

The impact of geometric characteristics on traffic risk is reflected through identifying conflict points on roads,traffic accidents, and any other unforeseen situation that is inherently hazardous for traffic participants. In order to identify the road sections with the highest risk, it is necessary to consider a number of criteria that affect risk, and conduct extensive empirical research, analysis and data synthesis. This paper evaluates 9 sections of two-lane roads in the territory of Bosnia and Herzegovina (the Republic of Srpska) using an integrated Multi-Criteria Decision-Making (MCDM) model.To determine the significance of 8 criteria for the evaluation of the sections, it was applied a subjective–objective model consisting of 3 methods: (1) CRiteria Importance Through Inter-criteria Correlation (CRITIC), (2) FUll COnsistency Method (FUCOM) and (3) fuzzy PIvot Pairwise RElative Criteria Importance Assessment (PIPRECIA). The aggregation of the criterion values obtained using the methods yielded the final criterion values. Measurement Alternatives and Ranking according to COmpromise Solution (MARCOS) method was used to evaluate the sections and determine their objective diversity. The obtained results identified one location as extremely hazardous by most of analysed input parameters. The section with the highest risk is the Rudanka – Doboj section (A4), which represents a section of the road infrastructure of the 105 road. The validation of the results obtained by applying the integrated MCDM model was performed through an extensive sensitivity analysis. The weights of criteria were observed through initially individual methods implemented in the MARCOS method. Then, a comparative analysis was performed with 6 other MCDM methods and Spearman’s Correlation Coefficient (SCC) was calculated as a statistical indicator of rank correlation in a sensitivity analysis. In addition,the Standard Deviation (STDEV) of the obtained results was determined.

A driving simulator study to evaluate the effects of different types of median separation on driving behavior on 2 + 1 roads

In recent years, several countries have started to introduce 2 + 1 roads into their road networks. Although some studies have recognized the great benefits of using 2 + 1 roads, few studies have investigated the effects of different design features of 2 + 1 roads on driver behavior and driving performance, including the type of median separation between opposing traffic flows. The overall aim of this driving simulator study is to determine whether different types of median separation on 2 + 1 roads affect driving behavior, and to provide new insights for designing more effective and safer 2 + 1 roads. A driving simulator study was carried out, and forty-six participants took part in the experiments. The scenario exactly reproduced an existing two-lane rural road in Poland where 2 + 1 sections are implemented; four different median separation types were tested: 1) double-line markings only; 2) reflective elements; 3) flexible guideposts; 4) cable barriers. The effects of the different types of median separation on driving behavior were statistically analyzed using data from 184 simulation tests. The results of the study suggest that the type of median separation significantly affects driving behavior on 2 + 1 roads. While the driving speeds on the passing lane did not differ significantly between the four configurations of the median separation, the lateral position of the passing vehicle on the additional lane was found to be significantly influenced by the type of separation, with a greater distance from the median recorded when the cable barriers were implemented. The potential of using driving simulation to test different solutions for 2 + 1 roads and select the most effective alternative in terms of safety and operation is demonstrated in this study. The results of this study can also be used to improve the behavioral models that can be implemented in the traffic micro-simulation of 2 + 1 road conditions.

Speed Behavior of Heterogeneous Traffic on Two-Lane Rural Roads in Malaysia

Highway geometry is a significant factor that affects the efficiency and safety of highway systems. The present study aims to investigate the speed behavior of various vehicle classes on the horizontal alignment of two-lane rural roads. An automatic data collection system based on a pressure sensor was employed to collect the speed of each individual vehicle, vehicle type, and headway at seven sites in each travel direction. The 85th percentile speed under free-flow conditions was used to observe the relationship between the operating speeds of various vehicle classes at consecutive curve points and the effect of the travel direction, time of day, and curve radius on the operating speed of the vehicle. A one-way ANOVA was employed to evaluate whether there is a significant difference in speed on horizontal curves. Then, a Tukey post hoc test was used to assess the significance of the difference in speed across four classes of vehicles. The results revealed that the horizontal curve affects the operating speed for all vehicle classes. A curve radius of less than 500 m, the travel direction, and the time of day are significant variables that affect the speed of all vehicle classes. The findings from this study can provide insight to transportation engineers for safer road design of horizontal curves and to assess traffic safety based on actual speed behavior.

The effect of road-based mortality on a local population of newts along a narrow two-lane road in California

Numerous studies have documented high numbers of amphibians killed by vehicular strikes on roads. This direct mortality can cause population declines and extirpations, but in some cases the declines might be masked, initially, by large population sizes. Population viability analysis can help discern population trajectories and identify incipient declines. We applied this tool to a situation in Santa Clara County, California where a dead-on-the-road carcass survey in 2017 demonstrated that a large number of newts in the genus Taricha were being killed by vehicles using a small two-lane road (Alma Bridge Road) most likely during annual breeding migrations to a local reservoir (Lexington Reservoir). To help determine the effect of this road-based mortality on the California newt (T. torosa) population, we conducted a drift fence/pitfall trap array study on the road during the 2020–2021 breeding season. Drift fence/pitfall trap arrays were installed at six locations along a 6.6-km stretch of the road and daily surveys were conducted at these arrays over a 148-day period from mid-November to end of March. Daily traffic and precipitation data were also recorded to help inform timing of proposed mitigation efforts. Concurrently, a group of community scientists conducted a dead-on-the-road carcass survey over the entire 6.6-km study area. We calculated the number of adult newts attempting to cross Alma Bridge Road at the arrays and the associated road-based mortality rates. Then, we combined our array results with road mortality data provided by the community scientists to estimate the number of adult California newts attempting to cross the road and their mortality rates over the entire study area during the survey period. We then incorporated this data into a population viability model to determine whether this road-based mortality rate might, if left unabated, lead to a reduction in, and possibly the eventual extirpation of, the local population of T. torosa breeding in Lexington Reservoir. The model indicated that this population would be extirpated in approximately 92 years. Because the road has been in use for approximately 67 years, we discussed the possible reasons why this population is currently extant and experiencing this high level of road-based mortality.

Evaluation of Automatic Prediction of Small Horizontal Curve Attributes of Mountain Roads in GIS Environments

Road curve attributes can be determined by using Geographic Information System (GIS) to be used in road vehicle traffic safety and planning studies. This study involves analyzing the GIS-based estimation accuracy in the length, radius and the number of small horizontal road curves on a two-lane rural road and a forest road. The prediction success of horizontal curve attributes was investigated using digitized raw and generalized/simplified road segments. Two different roads were examined, involving 20 test groups and two control groups, using 22 datasets obtained from digitized and surveyed roads based on satellite imagery, GIS estimates, and field measurements. Confusion matrix tables were also used to evaluate the prediction accuracy of horizontal curve geometry. F-score, Mathews Correlation Coefficient, Bookmaker Informedness and Balanced Accuracy were used to investigate the performance of test groups. The Kruskal–Wallis test was used to analyze the statistical relationships between the data. Compared to the Bezier generalization algorithm, the Douglas–Peucker algorithm showed the most accurate horizontal curve predictions at generalization tolerances of 0.8 m and 1 m. The results show that the generalization tolerance level contributes to the prediction accuracy of the number, curve radius, and length of the horizontal curves, which vary with the tolerance value. Thus, this study underlined the importance of calculating generalizations and tolerances following a manual road digitization.

Modeling of Operating Speeds as a Function of Longitudinal Gradient in Local Conditions on Two-Lane Roads

The operating speed is the average value of the speed of traffic flow under normal conditions, i.e., the conditions of mutual interference of traffic participants. The operating speed serves as a gauge for how well a given roadway is performing under the applicable traffic conditions. All key decisions in the management of the growth and utilization of a road network, including planning, designing, evaluating, and implementing road projects, depend on accurate measures of capacity and level of service. This paper aims to develop a recommended model for operating speed on two-lane roads under local conditions by analyzing the operating speeds of the traffic flow on representative sections of such roads. Through the modeling process, the values of the 85th percentile of the operating speed were determined, and compared with relevant studies. The results show that the authors have successfully modeled operating speeds as a function of longitudinal gradient in local conditions on two-lane roads.

Driving around bends with or without shoulders: The influence of bend direction

Paved shoulders have long been used to create “forgiving” roads where drivers can maintain control of their vehicles even when as they drift out of the lane. While the safety benefits of shoulders have been well documented, their effects on driver behavior around curves have scarcely been examined. The purpose of this paper is to fill this gap by assessing whether the addition of shoulders affects driver behavior differently as a function of bend direction. Driver behavior in a driving simulator was analyzed on left and right curves of two-lane rural roads in the presence and absence of 0.75-m and 1.25-m shoulders. The results demonstrated significant changes in drivers’ lateral control when shoulders were provided. In the absence of oncoming traffic, the shoulders caused participants to deviate more toward the inner lane edge at curve entry, at the apex and at the innermost position on right bends but not left ones. In the presence of oncoming traffic, this also occurred at the apex and the innermost position, leading participants to spend more time off the lane on right curves. Participants did not slow down in either traffic condition to compensate for steering farther inside, thereby increasing the risk of lane departure on right curves equipped with shoulders. These findings highlight the direction-specific influence of shoulders on a driver’s steering control when driving around bends. They provide arguments supporting the idea that drivers view paved shoulders as a new field of safe travel on right curves. Recommendations are made to encourage drivers to keep their vehicle within the lane on right bends and to prevent potential interference with cyclists when a shoulder is present.

Road Safety Audit Findings on Two-Lane Road: Case Study in Greece

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The Impact of Transportation Traffic Noise on Merauke City Road Crossing

Noise caused by transportation significantly exceeds the 55 dBA. The purpose of this study was to determine the level of transportation traffic noise at the Merauke city crossing and its solutions. Noise caused The lack of proper attention to the impact of noise from traffic flow at a crossroads. The Development of additional techniques for noise reduction in this area is needed. The results obtained are very important for areas with solutions at every highway intersection The results obtained are very important knowing the noise above the standard value at every highway intersection. This research develops techniques to reduce transportation traffic noise at the crossroads of Merauke city which are applied in design practice. Experimental studies in real conditions in the characteristic areas of Merauke City using sound level meter measurements. This research was carried out experimentally by taking measurements at each crossroads and theoretical solving methods. The good convergence results confirm the impact of noise on the immediate area with a slightly higher crossing than the value on a normal two-lane road. The proposed solution will allow providing additional protection against transportation noise.

Full-scale experimental study on fire characteristics induced by double fire sources in a two-lane road tunnel

The vehicle collisions, intense heat radiation and convection from flame and high-temperature smoke can easily cause double-source fire disasters in tunnels. In this paper, four full-scale fire experiments were performed in Jiangpu road tunnel to investigate the characteristics of double fire sources. The whole process of the ventilation velocity, heat release rate, longitudinal ceiling temperature, vertical temperature, carbon monoxide and flame deflection angle are analyzed. The results indicate that the interaction between the double fire sources affects the heat release rate and flame deflection angle and other parameters of each fire source. The ventilation and the fire source spacing can change the coupling state of thermal feedback mechanism and the shielding and entrainment effect of double fire sources. The fire source spacing affects the interaction mechanism and the smoke flow state between the ceiling jets of the double fire sources, which leads to the difference in the longitudinal ceiling temperature distribution between the double fire sources. According to the characteristics of smoke movement between double fire sources, the schematic diagrams of ceiling jets between double fire sources are established. The longitudinal ceiling temperature rise of double fire sources is analyzed from the perspective of steady state and unsteady state. The longitudinal ceiling temperature data of full-scale fire tests is compared with the prediction models proposed by other researchers. The “barrier effect” phenomenon was also observed in the double-source fire tests, especially in the vertical smoke temperature. The findings contribute to deepening the understanding of the fire characteristics of the double-source fire disasters.

A Conflict Measures-Based Extreme Value Theory Approach to Predicting Truck Collisions and Identifying High-Risk Scenes on Two-Lane Rural Highways

Collision risk identification and prediction is an effective means to prevent truck accidents. However, most existing studies focus only on highways, not on two-lane rural highways. To predict truck collision probabilities and identify high-risk scenes on two-lane rural highways, this study first calculated time to collision and post-encroachment time using high-precision trajectory data and combined them with extreme value theory to predict the truck collision probability. Subsequently, a traffic feature parameter system was constructed with the driving behavior risk parameter. Furthermore, machine learning algorithms were used to identify critical feature parameters that affect truck collision risk. Eventually, extreme value theory based on time to collision and post-encroachment time incorporated a machine learning algorithm to identify high-risk truck driving scenes. The experiments showed that bivariate extreme value theory integrates the applicability of time to collision and post-encroachment time for different driving trajectories of trucks, resulting in significantly better prediction performances than univariate extreme value theory. Additionally, the horizontal curve radius has the most critical impact on truck collision; when a truck is driving on two-lane rural highways with a horizontal curve radius of 227 m or less, the frequency and probability of collision will be higher, and deceleration devices and central guardrail barriers can be installed to reduce risk. Second is the driving behavior risk: the driving behavior of truck drivers on two-lane rural highways has high-risk, and we recommend the installation of speed cameras on two-lane rural roads to control the driving speed of trucks and thus avoid dangerous driving behaviors. This study extends the evaluation method of truck collisions on two-lane rural highways from univariate to bivariate and provides a basis for the design of two-lane rural highways and the development of real-time dynamic warning systems and enforcement for trucks, which will help prevent and control truck collisions and alleviate safety problems on two-lane rural highways.

Online and Predictive Warning System for Forced Lane Changes Using Risk Maps

The survival analysis of driving trajectories allows for holistic evaluations of car-related risks caused by collisions or curvy roads. This analysis has advantages over common Time-To-X indicators, such as its predictive and probabilistic nature. However, so far, the theoretical risks have not been demonstrated in real-world environments. In this paper, we therefore present Risk Maps (RM) for online warning support in situations with forced lane changes, due to the end of roads. For this purpose, we first unify sensor data in a Relational Local Dynamic Map (R-LDM). RM is afterwards able to be run in real-time and efficiently probes a range of situations in order to determine risk-minimizing behaviors. Hereby, we focus on the improvement of uncertainty-awareness and transparency of the system. Risk, utility and comfort costs are included in a single formula and are intuitively visualized to the driver. In the conducted experiments, a low-cost sensor setup with a GNSS receiver for localization and multiple cameras for object detection are leveraged. The final system is successfully applied on two-lane roads and recommends lane change advices, which are separated in gap and no-gap indications. These results are promising and present an important step towards interpretable safety.

Improved Horizontal Curve Design Consistency Approach Using Steady-State Bicycle Model Combined with Realistic Speeds and Path Radii

Three safety concerns have been identified in the conventional design consistency assessment procedure for horizontal curves: approximation of the vehicle by the point-mass model, use of unrealistic speeds, and the assumption that the path radius is equal to the design curve radius. This study presents a novel approach to the consistency assessment of horizontal curves in terms of vehicle stability (represented as the safety margin). The novel approach involves calculating the safety margins using the steady-state bicycle model to account for the nonuniform distribution of friction among individual axles due to grade and speed changes and using more-realistic driver behavior parameters. In this study, the realistic driver behavior parameters refer to the modeled operating speeds and calculated vehicle path radii, which were defined based on naturalistic driving data collected through a real-world experiment on a section of a two-lane state road using a GPS device. The analysis showed that the traditional safety margins for sharp curves are unrealistically large compared with the margins defined by the proposed approach; this indicates that the conventional approach uses a larger friction margin than the optimum friction margin. Consequently, the conventional approach results in the application of curves with radii smaller than those required for safe driving. Moreover, the results show that braking on a sharp curve on a steep downgrade is the most critical situation for the loss of lateral vehicle stability. Overall, this study highlights the significance of incorporating additional factors in the design procedure for horizontal curves that affect the safety of the curve, which are not considered in the point-mass model. The most significant factors considered in this study were the grade, driving maneuver in terms of speed change, operating speed, and vehicle path radius.

IoV-Based Mathematic Model for Platoon Give Way to Emergency Vehicles Promptly

When traffic density on urban roads is relatively large, it is difficult for a large number of O-vehicles (O-vehicles) in front of emergency vehicles (E-vehicles) to give way in a short time, resulting in a delay of E-vehicles. This study aimed to design an automatic way-giving system based on vehicle-to-vehicle communication (V2V) in the internet of vehicles (IoV). Also, a control algorithm was proposed for the platoon to give way to the E-vehicle in the minimum time, the factors such as the traffic density, number of vehicles in the platoon, the initial state, and speed limit were considered in this paper. The algorithm firstly calculated the dynamic adjustment trajectory for the platoon to complete the lane change, the adjustment time, and the minimum distance between the E-vehicle and the platoon at the beginning of lane change, to guide the platoon while changing the lane. A simulator utility was developed to interface with the microscopic traffic simulation package Simulation of Urban Mobility (SUMO) by using the Python program. Lastly, a two-lane road segment was simulated to evaluate the effectiveness of the control algorithm of automatic way-giving system, and its performance is compared with conventional vehicle operation. The results demonstrated that the operating efficiency of E-vehicles can be improved by 12.65% and the operating efficiency of O-vehicles can only be decreased by 3.25% by the automatic way-giving system. Besides, the notification distance is a key factor in affecting the operating efficiency of E-vehicles and O-vehicles.

Safe, Smooth, and Fair Rule-Based Cooperative Lane Change Control for Sudden Obstacle Avoidance on a Multi-Lane Road

When an unexpected obstacle occupies some of the lanes on a multi-lane highway, connected vehicles (CVs) may be able to avoid it cooperatively. For example, a CV that detects the obstacle first can immediately notify the following vehicles of the obstacle by using vehicle-to-vehicle (V2V) communication. In turn, the following vehicles can take action to avoid the obstacle smoothly using wide range behind the obstacle without sacrificing safety and ride comfort. In this study, we propose a method to realize safe, smooth, and fair wide-range cooperative lane changing, reacting to a sudden obstacle on the road. The proposed method is based on the authors’ previous work, which utilizes multi-hop communication to share the obstacle position and controls the inter-vehicular distance of vehicles away from the obstacle to assist in a smooth lane changing operation, while existing lane-changing methods for CVs focus on microscopic operation around the obstacle. Though the previous work treats only a two-lane road, the proposed method is extended to work on a three- or more lane road assuming only one lane is blocked. In the proposed scheme, each vehicle approaching the obstacle selects a lane to change to in accordance with the obstacle’s location and the vehicle density in each lane estimated from the beacon messages broadcast by each CV, thereby improving traffic fairness among all lanes without degrading safety or ride comfort. We confirmed the effectiveness of the proposed scheme on realizing fairness among lanes, safety, ride comfort, and traffic throughput through comprehensive simulations of a two-lane road and a three-lane road with various traffic scenarios.

Overview of River Hydrological Issues in Kakarbhitta-Pathlaiya Road Segment of East-West Highway of Nepal

The East-West Highway of Nepal is the main trade and physical mobility corridor and of a two-lane bituminous road. Therefore, the Government of Nepal (GoN) is planning to improve it to a standard four-lane highway. In the first phase, the Government of Nepal is planning to upgrade the Kakarbhitta-Pathlaiya road which is the segment of the East-West Highway. It is vital to examine the river hydrology accurately for the appropriate location and design of the structures associated with it. This study aims to work out the features of flood and sediment of the major rivers intersecting the Kakarbhitta-Pathlaiya road. A review of the previous studies and field observation via a walk-through survey was conducted to assess the hydrological issues. The road segment passes through the Terai. The study revealed that the issues of flooding and inundation within the Terai are more critical, and the rivers crossing the road segment transport significant amounts of sediment as well. In the stages of planning and design of the road segment, the capacity of the rivers must be enhanced for transporting water and sediment in the places of bridges. Besides, watershed management techniques and integrated water resources management approaches should be intervened.

Safety evaluation of centre line, edge line, and dual application rumble strips on Ontario two-lane rural roads

The study builds on previous rumble strip safety evaluations by providing some Canadian-specific experience and in the process offering some definitive insights into differences in safety effects between installations on curved and tangent segments. An empirical Bayes before–after study estimated crash modification factors (CMFs) for installing edge line rumble strips (ELRS) and centerline rumble strips (CLRS), separately and in combination, on two-lane rural roads in Ontario. Separate CMFs were estimated for ELRS and CLRS for curved and tangent segments. The estimated CMFs indicate that rumble strips can be beneficial, except for CLRS on curved segments, and especially if applied in combination on tangents. The results also indicate that edge line and dual rumble strips are more effective on curved segments, so priority should be given to their application on such segments. It is noteworthy that dual application is more safety effective than either CLRS or ELRS, for tangents and overall.