Straight Road Sections Research Articles

Freight Transport Pollution Propagation at Urban Areas Based on Szczecin Example

Transport is one of the main sectors of the economy, which has a significant impact on the economic development of the country. The increase in the development of transport and transport infrastructure itself definitely develops the economic potential of the country, strengthens its economic, social cohesion and economic competitiveness. Depending on the type of emitted substances, transport pollution is of local or global nature. Considering the emission of pollutants in urban agglomeration, emitted toxic compounds mainly impact the local pollution of the environment. The primary toxic pollutants emitted into the environment from combustion of fuels include mainly: carbon monoxide CO, aliphatic and aromatic hydrocarbons (including benzo(a)pyrene), sulphur dioxide SO2, nitric oxide NOx and particulate matter PM (soot, tar) and heavy metals. The paper is focused on model of urban freight transport influences on city environment. The road, as a line source of pollution, is included in the model with a set of emitters and concerns finite straight line with a constant source of emissions per unit length and a constant effective source height. In order to perform modelling it is necessary to divide vehicles into categories, which forms the basis for determining the characteristics of the emission. The model will cover simulation of the distribution of pollutants for vehicle traffic stream in a communication network of the city. In the first case, study will be conducted for the straight sections of road, and then combined into a junction, which will allow for identification of the impact of traffic on air quality in different parts of the urban area. The example area of analysis includes chosen streets in Szczecin city centre. The basis of the analysis are the data collected during the survey and using traffic detectors.

Measuring Algorithm for the Distance to a Preceding Vehicle on Curve Road Using On-Board Monocular Camera

Due to more severe challenges of traffic safety problems, the Advanced Driver Assistance Systems (ADAS) has received widespread attention. Measuring the distance to a preceding vehicle is important for ADAS. However, the existing algorithm focuses more on straight road sections than on curve measurements. In this paper, we present a novel measuring algorithm for the distance to a preceding vehicle on a curve road using on-board monocular camera. Firstly, the characteristics of driving on the curve road is analyzed and the recognition of the preceding vehicle road area is proposed. Then, the vehicle detection and distance measuring algorithms are investigated. We have verified these algorithms on real road driving. The experimental results show that this method proposed in the paper can detect the preceding vehicle on curve roads and accurately calculate the longitudinal distance and horizontal distance to the preceding vehicle.

Circumstances and causes of fatal cycling crashes in the Czech Republic

ABSTRACTObjectives: The circumstances and causes of death of 129 cyclists registered in the Olomouc and the Zlín regions, the Czech Republic, between 2005 and 2013 were the subject of this study.Methods: We analyzed the autopsy reports, where the principal cause of death was stated, and obtained a detailed description of the circumstances recorded by the police officers.Results: Eighty-three cases (64.3% of the set) were collisions involving a motor vehicle. The driver was the guilty party in 57 cases (68.7%) and the cyclist in the remaining 26 cases (31.3%). The most frequent cause of the crash was connected with right of way (29 cases). Cars were involved in 52 cases; heavy vehicles, including buses, in 26 cases; and motorcycles in 5 cases. Single-vehicle crashes consisted of 43 (33.3%) cases. We divided this group into 3 subgroups based on whether the particular case could be attributed to a cyclist having lost control of the bicycle (31 cases) or to other particular causes. Sixty-eight cases (52.7%) of fatal outcomes were directly linked to intracranial injuries. Multiple injuries were the principal cause of death in 19 cases (14.7%), followed by hemorrhagic traumatic shock (12 cases, 9.3%). Seventy-two (55.8%) cyclists died immediately after the crash and 23 (17.8%) cyclists died within a day of the accident.Conclusions: Trucks were more dangerous to cyclists than cars at intersections, whereas cars were more dangerous on straight sections. The most important pattern was identified as a motor vehicle hitting a cyclist from behind on a straight road section. We identified a strong underestimation of natural death as a cause of cycling fatalities in the official police reports.

Motorcyclists’ road safety related behavior at access points on primary roads in Malaysia – A case study

An observational study, focusing on motorcyclists, was conducted between June and August 2012 at access points on straight road sections of primary roads in Malaysia. This was done in order to gain more insight into the actual road traffic situation at these sites. The majority of the motorcyclists kept to the speed limit and lowered speed when approaching an access point, especially when road users were on it. However, when the primary road traffic volume was high, they maintained higher speeds compared to other vehicles. The behavioral observations revealed a risky right turning movement, i.e. Opposite Indirect Right Turn (OIRT), from the access point into the primary road. Motorcyclists generally had a high compliance rate of helmet (except for female motorcyclists) and headlight usage. Motorcyclists attempting to enter the primary road were poor at utilizing the turning indicator. They were observed not to turn their heads to look for vehicles when entering a road with a low volume of traffic, compared to entering a road with a high volume of traffic. Most of the motorcyclists did not comply with the stop line rule, especially those who made the OIRT. Motorcyclists entering from the access point are involved in serious traffic conflicts to about the same extent as other vehicles. Moreover, motorcyclists who stopped at the stop line and made a right turn into the primary road by accepting a short gap, resulting in a time lag of less than 4s, were involved in the majority of the serious conflicts.

Exploration of motorcyclists’ behavior at access points of a Malaysian primary road – A qualitative observation study

The majority of motorcycle accident fatalities in Malaysia occur on primary roads, especially at access points situated along straight road sections. To explore the behavioral factors that may contribute to motorcyclists being involved in hazardous situations at these locations and to develop working hypotheses for a consecutive quantitative study, a qualitative observational study was carried out. Six subject riders exiting from the access point of a primary road were observed. The observations were narrated in detail and coding was used as a means to analyze the observations and divide (and sub-divide) them into categories, which were then segregated into themes. The results of the study produced a number of hypotheses based on various combination themes, i.e. background condition, motorcyclists’ behavior before exit, motorcyclists’ behavior during exit, and involvement in serious traffic conflicts. The newly developed hypotheses from this study are presented and discussed; they are put forward to be tested in a consecutive quantitative observational study. This study also presents novelty in terms of applying a qualitative observational study on motorcyclists, which can be easily adopted not only for Malaysian researches but also all countries that face similar motorcycle problems at access points or junctions.

On-road experiment to assess drivers’ detection of roadside targets as a function of headlight system, target placement, and target reflectance

Adaptive headlights swivel with steering input to keep the beams on the roadway as drivers negotiate curves. To assess the effects of this feature on driver’s visual performance, a field experiment was conducted at night on a rural, unlit, and unlined two-lane road during which 20 adult participant drivers searched a set of 60 targets. High- (n=30) and low- (n=30) reflectance targets were evenly distributed on straight road sections and on the inside or outside of curves. Participants completed three target detection trials: once with adaptive high-intensity discharge (HID) headlights, once with fixed HID headlights, and once with fixed halogen headlights. Results indicated the adaptive HID headlights helped drivers detect targets that were most difficult to see (low reflectance) at the points in curves found by other researchers to be most crucial for successful navigation (inside apex). For targets placed on straight stretches of road or on the outside of curves, the adaptive feature provided no significant improvement in target detection. However, the pattern of results indicate that HID lamps whether fixed or adaptive improved target detection somewhat, suggesting that part of the real world crash reduction measured for this adaptive system (Highway Loss Data Institute (HLDI), 2012a) may be due to the differences in the light source (HID vs. halogen). Depending on the scenario, the estimated benefits to driver response time associated with the tested adaptive (swiveling HID) headlights ranged from 200 to 380ms compared with the fixed headlight systems tested.

An approach to detect and delineate street curbs from MLS 3D point cloud data

This paper is focused on the detection and delineation of curbs and street boundaries using a 3D point cloud registered by a mobile laser scanner (MLS) system. Non-manual roadside detection is an important issue in road maintenance, 3D urban modeling, and autonomous navigation fields. The proposed method is able to detect upper and lower curb edges and delineate even occluded or hidden roadsides in most environments. It is based on a rasterization and segmentation approach for curb detection while preserving the reference to the original point cloud avoiding loss of information. The method was tested using two point clouds from various street scenes measured by an Optech Lynx Mobile Mapper System, providing accuracies in curb extraction over 95% in both datasets. • We propose a method to detect street curbs from 3D point clouds. • Image processing techniques are used to detect linear features. • The method is valid for both straight and curved road sections. • Occluded areas between straight road sections are detected. • The method determines the upper and lower edges of detected curbs.

Road Traffic Accident Characteristics in Dhaka, Bangladesh

Over the next decade, developing countries like Bangladesh will experience an alarming increase in road accidents and this will continue to remain as a serious challenge. Developing countries are experiencing a very high growth rate of vehicles, which is doubling the vehicle fleet in some countries in even five years. The complexity of the road environment with mixed traffic is another reality of road transportation in Dhaka, Bangladesh, where road planning and designs are not appropriate for mixed traffic conditions. Of particular concern are the urban intersections where differential approach speed is a major problem. The heterogeneity of traffic exceeding the capacity, plying of modes with varying speed and maneuvering time make the road links as well as intersections of Dhaka even more complex. The objectives of the study are to determine the characteristics of the road traffic accidents of Dhaka city for the following parameters: a) Traffic accident trend b) Traffic Control Parameters c) Traffic Accident at Junctions d) Traffic Control and Road Dividers e) Traffic Accidents and Road Geometry. Traffic accident data for the period of year 2007-2011 were collected from the Police Stations of the Dhaka Metropolitan Police (DMP) area. The data were compiled from the Police Reports accident by accident and analyzed using an MS Access based database and additionally an ArcGIS software for the selected variables. All the roadway sections and intersections of Dhaka Metropolitan Police (DMP) were considered in the study. A total number of two thousand seven hundred twenty (2720) accidents that were recorded by police during the period of year 2007-2011 were analyzed. The study revealed that a) number of accidents in Dhaka is reducing by more than ten (10) percent every year b) Sixty three percent (63%) of the accidents took place where there was no traffic control c) Only twenty nine percent (29%) of the accidents took place at intersection areas and T-junctions were found to be the most vulnerable junction type d) Seventy three percent (73%) accidents occurred on divided roadways or where only one-way traffic movement existed e) Ninety seven percent (97%) of the accidents occurred on straight road sections. Improvement of the traffic accident data collection system in Dhaka is necessary. Detailed study on under-reporting of traffic accident is also recommended.

The effect of different delineator post configurations on driver speed in night-time traffic: A driving simulator study

The aim of the study was to investigate how different delineator post configurations affect driver speed in night-time traffic. In addition, the potential speed effect of introducing a secondary task was investigated. The study was carried out in a car simulator on a road stretch including straight road sections as well as curves with different radii. Fourteen drivers participated in the study and the results show that absence of delineator posts leads to reduced speed. However, provided that there are delineator posts continuously present along the road, the overall driver speed is basically the same, regardless of the spacing between the delineator posts. The results also imply that to reduce driver speed in curves with small radius, using more compact spacing of posts in these curves as compared to in curves with a larger radius, could be a potential strategy. Additionally, the speed reducing effect of a secondary task was only prevailing where the task was initiated.

Beeping ADAS: Reflexive effect on drivers’ behavior

Advanced driver assistance systems (ADAS) are designed to assist individuals while they are at the wheel of a motor vehicle. Many ADAS emit acoustic signals when parameters such as drivers’ maintained speed exceed given thresholds. This study examines the early and late effects on lane keeping and speed maintenance produced by both the onset of and prolonged exposure to a continuous beep like those emitted by ADAS. While driving a simulator along a straight road section, participants were presented with a single, continuous beep and its effect on drivers’ behavior was investigated. The findings show that the abrupt onset of beeping startles drivers, causing them to take their foot off the accelerator and, momentarily, deviate from the correct trajectory within the lane. This behavior is to be considered particularly dangerous, since ADAS are designed to beep when driving conditions become critical, i.e., precisely when drivers should not be distracted and should concentrate on the driving task. In response to this disturbance, drivers are observed to execute corrective behavior, i.e., braking, in order to regain control of their vehicle. These results support the idea that the abrupt onset of an acoustic stimulus like those emitted by ADAS can potentially disrupt driving. Researchers and car manufacturers should therefore consider this aspect of in-car technology interactions when designing new ADAS.

Study of Vehicles Lateral Movement in Non-lane Discipline Traffic Stream on a Straight Road

Driving safety can be achieved by the prevention of risky situations which may require the knowledge of vehicle dynamic state as well as road geometry. In India the traffic condition is very complex in nature. There exists a mixed traffic flow with no lane discipline. Hence the lateral movement of the vehicles are very high due to no lane discipline. Lateral acceleration is one of the most important vehicle dynamic variables. Several studies are done by various authors on lateral acceleration in curves. It is also very important to study the lateral movement of the vehicle in case of straight road section to know the vehicles maneuver. The main purpose of this study is to observe the lateral acceleration, speed values in the moderate traffic conditions and to investigate the relationship between the vehicle longitude speeds with the lateral characteristics in the Indian traffic condition. Relation between lateral acceleration and heading angle with longitudinal speed is explored for the three different types of vehicles. There exists an inverse relation between longitudinal speed and lateral acceleration for all the three types of vehicle except at lower speeds. The vehicles rate of change of heading angle also reduces at higher speed.

Dynamic risk simulation to assess natural hazards risk along roads

Abstract. Risk generated by natural hazards on roads is usually calculated with equations integrating various parameters related to hazard and traffic. These are static variables, like an average number of vehicles crossing this section every day and an average vehicle speed. This methodology cannot take into account dynamic variations of traffic and interactions between vehicles such as speed modifications due to windy roads, slowdowns resulting from saturated traffic or vehicle tailbacks forming in front of traffic lights. Here we show, by means of a dynamic traffic simulator, that traffic variations may greatly influence the risk estimation over time. The risk is analysed on several sections of an Alpine road in Switzerland using a dynamic vehicles approach, and compared with the results of the static methodology. It demonstrates that risk can significantly increase on sinuous sections because of decreasing vehicle speed. For example, along an 800 m-long section of road containing two hairpin bends, the dynamic risk is about 50% higher than the static one. Badly placed signalization, slowing down, or stopping the vehicles in a hazardous area may increase the risk by about 150% (i.e. 2.5 times higher) along a straight road section where vehicles speed is high. A more realistic risk can thus be obtained from a dynamic approach, especially on mountain roads. The dynamic traffic simulator developed for this work appears to be a helpful tool to support decision-making in reducing risk on mountain roads and it shows the importance of keeping the traffic moving as freely as possible.

A Comparison of 25 High Speed Tire Disablements Involving Full and Partial Tread Separations

Tire tread separation events, a category of tire disablements, can be sub-categorized into two main types of separations. These include full tread separations, in which the tread around the entire circumference of the tire separates from the tire carcass, and partial tread separations, in which a portion of the tread separates and the flap remains attached to the tire for an extended period of time. In either case, the tire can remain inflated or lose air. Relatively, there have been few partial tire tread separation tests presented in the literature compared to full tread separation tests. In this study, the results of 25 full and partial tire tread separation tests, conducted with a variety of vehicles at highway speeds, are reported. Cases in which the tire remains inflated and loses air pressure are both considered. The testing was performed on a straight section of road and primarily focused on rear tire disablements. The driver steering inputs required to keep the vehicle within its travel lane and the vehicle's dynamic response during the events were documented with video and data acquisition equipment. The results from the testing are presented and compared. It was found that the steering inputs required to keep the vehicle within its lane during a partial tread separation were similar in magnitude to those in the full separation testing. These results were also similar to the results of full separation testing documented by other researchers. In all cases, the vehicle was controlled within its lane with minor corrective steering. Figure 1 depicts video documentation and vehicle speed during one of the test runs. Language: en

The effect of road and environmental characteristics on pedestrian hit-and-run accidents in Ghana

The number of pedestrians who have died as a result of being hit by vehicles has increased in recent years, in addition to vehicle passenger deaths. Many pedestrians who were involved in road traffic accident died as a result of the driver leaving the pedestrian who was struck unattended at the scene of the accident. This paper seeks to determine the effect of road and environmental characteristics on pedestrian hit-and-run accidents in Ghana. Using pedestrian accident data extracted from the National Road Traffic Accident Database at the Building and Road Research Institute (BRRI) of the Council for Scientific and Industrial Research (CSIR), Ghana, a binary logit model was employed in the analysis. The results from the estimated model indicate that fatal accidents, unclear weather, nighttime conditions, and straight and flat road sections without medians and junctions significantly increase the likelihood that the vehicle driver will leave the scene after hitting a pedestrian. Thus, integrating median separation and speed humps into road design and construction and installing street lights will help to curb the problem of pedestrian hit-and-run accidents in Ghana.

A spatial and temporal analysis of child pedestrian crashes in Santiago, Chile

This paper presents a spatial and temporal analysis of child pedestrian crash data in Santiago, Chile during the period 2000–2008. First, this study identified seven critical areas with high child pedestrian crash risk employing kernel density estimation, and subsequently, statistically significant clusters of the main attributes associated to these crashes in each critical area were determined in a geographic information systems environment. Moran's I index test identified a positive spatial autocorrelation on crash contributing factors, time of day, straight road sections and intersections, and roads without traffic signs within the critical areas during the studied period, whereas a random spatial pattern was identified for crashes related to the age attribute. No statistical significance in the spatial relationship was obtained in child pedestrian crashes with respect to gender, weekday, and month of the year. The results from this research aid in determining the areas in which enhanced school-age child pedestrian safety is required by developing and implementing effective enforcement, educational, and engineering preventive measures.

Predication of Pavement Performance for Highway Sections with Special Geometric Features

AbstractThe current state-of-the-practice for pavement design only accounts for traffic load applicationwithout considering the speed and highway geometry as design criterion. This paper investigates theeffect of geometric design elements including horizontal curves, vertical gradients and U-turns onpavement performance at different traffic characteristics and pavement structures. The effects oftheses parameters on Pavement Condition Index (PCI) and International Roughness Index (IRI) wereinvestigated using simple, multiple, and stepwise linear regression to develop prediction models forspecial geometric sections. In this study, field data were collected for surface pavement distresses, forsections with special geometric features, varied traffic characteristics, and different pavementstructures. Comparison between the pavement conditions of sections with special geometric featuresand those of their reference straight road sections was performed. The results showed significantdifference between PCI of special geometric sections and their reference sections. So, the geometryfactor needs to be considered in structural design of pavements. This paper also showed that speed isone of the most important factors influencing pavement deterioration especially at upgrade sectionsand horizontal curves. Prediction models were built to forecast the pavement conditions for sectionswith vertical gradients and horizontal curves.

Motorcycle fatalities in Malaysia

Malaysia has the highest road fatality risk (per 100,000 population) among the ASEAN countries and more than 50% of the road accident fatalities involve motorcyclists. This study has collected and analysed data from the police, government authorities, and national and international research institutes. Only fatality data are used due to the severe underreporting of severe injuries (up to 600%) and slight injuries (up to 1400%). The analysis reveals that the highest numbers of motorcycle fatalities occur in rural locations (61%), on primary roads (62%) and on straight road sections (66%). The majority are riders (89%), 16 to 20years old (22.5%), and 90% of the motorcycles are privately owned. Of those involved in fatal accidents, 75% of the motorcyclists wear helmets, and 35% do not have proper licences. The highest number of fatalities by type of collision is ‘angular or side’ (27.5%). Although fatal motorcyclist crashes mostly involve ‘passenger cars’ (28%), motorcyclists are responsible for 50% of the collisions either by crashing singly (25%) or with other motorcyclists (25%). While male motorcyclists predominate (94% of fatalities), female motorcyclists aged 31 to 70, possessing ‘no licence’, not wearing helmets and travelling during the day, account for a higher percentage than male motorcyclists. Malaysia must acquire more motorcycle exposure data and establish an injury recording system and database based on hospital-records. To reduce motorcycle fatalities, it first has to understand why young male motorcyclists are prone to fatal crashes in the evenings and on weekends on rural primary roads, especially on straight road sections.

Integrated Driver–Vehicle–Infrastructure Road Departure Warning Unit

In this paper, a road-departure warning unit taking into account driver-vehicle-infrastructure (DVI) interactions is proposed. The longitudinal and lateral vehicle dynamics limits are analyzed to detect the road departure on loss of control. Vehicle positioning and time to lane crossing (TLC) are used to detect the road departure on a defect of guidance. Prevention of excessive longitudinal speed is handled through the computation of a critical longitudinal speed when approaching a curve and speed profile generation in the straight road section preceding the curve. For the lateral mode, the vehicle oversteering or understeering, the yaw motion, and the lateral acceleration are analyzed. The vehicle lateral displacement and the TLC values are also examined when the vehicle dynamics are not excessive. Necessary data for detection algorithms, which are not available from measurements, are estimated using an extended Kalman filter. The system consists of several subsystems, which work in parallel and provide warning through a dedicated human-machine interface (HMI). This road-departure warning system is experimentally tested on a test track using a prototype vehicle. It is found to be efficient and robust.

Driving simulators for robust comparisons: A case study evaluating road safety engineering treatments

Road authorities considering the implementation of speed management interventions should have access to the results of scientifically robust evaluations on which to base their decisions. However, studies that evaluate a diverse range of interventions with comparable metrics are rare, with most focussing on one type, for example, types of signage, perceptual countermeasures or physical traffic calming. This paper describes a driving simulator study designed to overcome these constraints. Twenty diverse speed-reducing treatments were developed and tested in urban and rural road environments. Forty participants encountered all the treatments allowing a comparison to be made with their driving behaviour when the treatment was not present. A number of speed parameters were developed to encapsulate the range of effects of the treatments. The results suggest that whilst straight sections of road are difficult to treat, speed reductions can be obtained by increasing risk perception. In contrast, alerting treatments had more effect at junctions, particularly in an urban environment; drivers approaching curves demonstrated improved speed adaptation if the curve radius was highlighted (either implicitly or explicitly). The study highlights how driving simulators can be used to overcome methodological constraints encountered in real-world evaluations of this type.

Determination of Traffic Flow Parameters in Different Traffic Flow Interaction Cases

Abstract Modelling of straight road section consisting of one traffic line gives the opportunity to simulate “follow the car” system. In general it looks like a line of vehicles, going one after another. Kinetic theory, used in this paper describes traffic flow system as a straight unbroken line with limited flow speed and concentration. Such model also gives the opportunity to derive traffic lines intersections. For example, intersection could be derived like a point with traffic lines coming and outgoing from this point by only changing boundary conditions. Mathematical model is built using characteristic method.