Real Traffic Conditions Research Articles

ФАКТОРЫ CНИЖЕНИЯ РИСКА СТОЛКНОВЕНИЯ АВТОТРАНСПОРТНЫХ МАШИН И ТРАВМИРОВАНИЯ ВОДИТЕЛЕЙ

Increasing the safety of drivers of motor vehicles (MV) used in rural and forestry is an urgent task due to the high level of injuries. Analysis of injury statistics of drivers of motor vehicles and conducted studies has revealed that these ma-chines are sources of increased danger in the performance of transport operations. For the functioning of a device that re-duces traumatism and increases the safety of MV drivers in carrying out transportation of agricultural products and removal of timber, it is necessary to know the magnitude of MV braking distance in real traffic conditions, which is determined theoretically. The imperfection of the methods for determining the real stopping distance of modern VMs used in forestry and agriculture is due to the fact that they do not take into account a number of operational and constructive factors. When determining the length of the braking distance according to the existing analytical dependencies, the error can be from 25% to 35%. Reducing the risk of collision of VM during transportation of agricultural products and performing logging operations is proposed to be provided by improving the method of determining the braking distance, taking into account the actual operating conditions. The results and conclusions made in this article can be useful for improving safety of agricultural and forestry vehicles on the roads

Field tests of a dynamic green driving strategy based on inter-vehicle communication

This paper presents the design and results for field tests regarding the environmental benefits in stop-and-go traffic of an algorithmic green driving strategy based on inter-vehicle communication (IVC), which was proposed in Yang and Jin (2014). The green driving strategy dynamically calculates advisory speed limits for vehicles equipped with IVC devices so as to smooth their speed profiles and reduce their emissions and fuel consumption. For the field tests, we develop a smartphone-based IVC system, in which vehicles’ speeds and locations are collected by GPS and accelerometer sensors embedded in smartphones, and communications among vehicles are enabled by specially designed smartphone applications, a central server, and 4G cellular networks. Six field tests are carried out on an uninterrupted ring road under slow or fast stop-and-go traffic conditions. We compare the performances of three alternatives: no green driving, heuristic green driving, and the IVC-based algorithmic green driving. Results show that heuristic green driving has better smoothing and environmental effects than no green driving, but the IVC-based algorithmic green driving outperforms both. In the future, we are interested in field tests under more realistic traffic conditions.

Motorcycle That See: Multifocal Stereo Vision Sensor for Advanced Safety Systems in Tilting Vehicles.

Advanced driver assistance systems, ADAS, have shown the possibility to anticipate crash accidents and effectively assist road users in critical traffic situations. This is not the case for motorcyclists, in fact ADAS for motorcycles are still barely developed. Our aim was to study a camera-based sensor for the application of preventive safety in tilting vehicles. We identified two road conflict situations for which automotive remote sensors installed in a tilting vehicle are likely to fail in the identification of critical obstacles. Accordingly, we set two experiments conducted in real traffic conditions to test our stereo vision sensor. Our promising results support the application of this type of sensors for advanced motorcycle safety applications.

Electric vehicle‐routing problem with charging demands and energy consumption

An electric vehicle-routing problem (EVRP) is developed to settle some operation distribution troubles such as battery energy limitations and difficulties in finding charging stations for electric vehicles (EVs). Meanwhile, in view of realistic traffic conditions and features of EVs, energy consumption with travel speed and cargo load is considered in the EVRP model. Moreover, to avoid the depletion of all battery power and ensure safe operation, EVs with insufficient battery power can be recharged at charging stations many times in transit. In conclusion, a large, realistic case study with the road network of Beijing urban, 100 customers and 30 charging stations is conducted to test the performance of the model and obtain an optimal operation scheme consisted of the routes, charging plan and driving paths. The EVRP model is solved based on the hybrid genetic algorithm to get the routes and charging plan. The dynamic Dijkstra algorithm with some improvements over the classical Dijkstra algorithm is applied to find the driving paths called the most energy efficient paths between any two adjacent visited nodes in the routes.

Functional and structural parameters of a paved road section constructed with mixed recycled aggregates from non-selected construction and demolition waste with excavation soil

This paper evaluates the lab and in situ mechanical properties of non-selected mixed recycled aggregates from construction and demolition waste (CDW) used as base and subbase unbound materials. Excavation materials are mixed with CDW to produce recycled mixed aggregates with soil, as well as a finer material referred to as mixed recycled soil. The research was divided into two different stages: a laboratory study characterizing the properties of recycling aggregates and a road test track evaluating the long-term performance of these materials under real traffic and weather conditions. During construction, several density, plate load, and falling weight deflectometer tests were performed to determine the bearing capacity of all layers. A laser profiler was also used to obtained the international roughness index. After the road was opened to traffic, a follow up of deflections and surface roughness was performed during the following seven years.Two different moduli calculation methods were used: back calculation and forward calculation. Both methods shown acceptable values for these recycled materials. Low quality recycled mixed aggregates can be used as substitutes for natural aggregates as unbound layers. The mechanical performance and surface roughness values obtained from the experimental road shown an acceptable behaviour.

Highlighting of the viscoelastic behaviour of interfaces in asphalt pavements – a possible origin to top-down cracking

Top-down cracking (TDC) is known to initiate and remain near the surface of bituminous pavements. The aim of this paper is twofold: (i) show experimental evidence of the viscoelastic behaviour of interface in asphalt pavements under some temperature conditions and (ii) show that taking into account such a behaviour could provide an explanation to the mechanism involved in the initiation of TDC. This paper documents the methodology used to investigate the behaviour of the upper interface from experimental tests. The mechanical response of the experimental pavement is evaluated using three models: (1) the elastic model, (2) the Huet–Sayegh viscoelastic model to account for the behaviour of asphalt layers and (3) same as 2, but with additional very thin viscoelastic layers to represent interfaces between the asphalt layers. The software ViscoRoute 2.0© is used to evaluate the stresses and the strains at different depths of the pavement. The comparison between the experimental results and the models clearly shows that model 3 is that yields the best fit. This model shows that significant tensile stresses and strains occur near the surface and at the interface between two asphalt layers. The transposition of the viscoelastic behaviour of interfaces to real traffic conditions could explain TDC as one of the damaging modes of asphalt pavements.

Road Traffic Monitoring System Based on Mobile Devices and Bluetooth Low Energy Beacons

The paper proposes a method, which utilizes mobile devices (smartphones) and Bluetooth beacons, to detect passing vehicles and recognize their classes. The traffic monitoring tasks are performed by analyzing strength of radio signal received by mobile devices from beacons that are placed on opposite sides of a road. This approach is suitable for crowd sourcing applications aimed at reducing travel time, congestion, and emissions. Advantages of the introduced method were demonstrated during experimental evaluation in real‐traffic conditions. Results of the experimental evaluation confirm that the proposed solution is effective in detecting three classes of vehicles (personal cars, semitrucks, and trucks). Extensive experiments were conducted to test different classification approaches and data aggregation methods. In comparison with state‐of‐the‐art RSSI‐based vehicle detection methods, higher accuracy was achieved by introducing a dedicated ensemble of random forest classifiers with majority voting.

Traffic Management using Logistic Regression with Fuzzy Logic

Traffic congestion is one of the major problems in most of the cities across the globe and it leads to several other problems like pollution, time wastage, long traffic queues on roads and may cause accidents. Improvement of Road infrastructure is not always the feasible solution to resolve the problem. In real life scenario shorter distance route towards the destination attracts majority of people and at times it may aggravate traffic jam conditions. Therefore, a real time traffic information for intelligent decision making to decide the route preference is required. Moreover, a system which considers the factor of distance towards the destination along with real time traffic situation on that route will add to the solution to the congestion problem. certain parameters such as distance, weather condition, road location, day of week and time are considered to formulate the problem and to find solutions to these problems This paper outlines a combination of logistic regression with fuzzy logic such that a smart decision to preferred path can be taken. It is used to compute the probability of each possible path by considering the real time traffic information, distance and road condition and later is used to take decisions in an uncertain scenario. Proposed Method considers the number of parameters like distance, weather condition, road location, day of week and time.

Simulation and Investigation of Tire Tread Blocks Interaction with Ice

The car tire is an essential subject analysing its interaction with the road. From tire’s tread condition, geometry and rubber compound depends grip and vehicle stability. This is especially relevant in winter time, when roads are covered with the layer of snow or ice. Generally, new tires are tested in real traffic conditions using vehicles. However, ensuring these conditions requires many resources and sometimes it could be a big challenge. For this reason, simulation of the tire interaction with the road becomes more important in nowadays tire researches. Since the tire is a complex engineering subject, the tire tread blocks could be separated for individual analysis. The interaction between the dry ice and the tread block with sipes was analysed using finite element analysis. The tread block was described using hyperelastic Mooney­Rivlin material model. The deformations, distribution of the contact pressure and shear stresses were obtained for the soft and hard rubber compounds with different vertical load conditions. Also a solid tread block interaction was analysed and it was found that values of contact pressure and shear stresses are much lower comparing to siped tread block.

Green Eco-Driving Effects in Non-Congested Cities

Despite technological advances in engines and fuels, the transportation sector is still one of the largest emitters of greenhouse gas (GHG). Driving patterns, including eco-driving techniques, are a complementary measure for saving GHG emissions. Most eco-driving studies so far have been conducted in large cities suffering chronic congestion problems. The aim of this research is therefore to analyse the potential of driver behaviour for reducing emissions in a small non-congested city. Driver performance parameters such as travel speeds, number of stops, revolutions per minute, and maximum acceleration-deceleration are also studied. The methodology is designed to measure the effect of both eco-driving and eco-routing under real traffic conditions. A campaign was carried out in the city of Caceres (Spain) to collect data on various types of roads under different traffic conditions. This research concludes that eco-driving leads to CO2 savings on all routes and road types of 17% in gasoline engines and 21% in diesel, although travel times are increased by 7.5% on average. The shortest route is also the most ecological, regardless of the traffic volume and characteristics, implying that consumption in non-congested cities depends mainly on distance travelled rather than driving patterns in terms of number of stops, speed and acceleration.

Torque characteristic of SI engine in dynamic operating states

The article presents torque characteristic of the engine in dynamic operating conditions as a function of engine speed and throttle opening angle. All mentioned parameters are analyzed as independent variables over time. To develop such a characteristic an artificial neural network is used. The training data were obtained from measurements carried out on the test bench on SI engine. The operating states reflect all possible configurations of these parameters, which may occur during use of the vehicle in real traffic conditions. The article shows design of an artificial neural network that allows to designate the required dependences. Moreover, it describes the fit of the model to the measurement data, which clearly indicates its correctness. Then the developed characteristic in dynamic states is compared with the characteristic in static working states. The differences between them for selected cases of engine operation states are presented. It shows the versatility of the presented method.

Phase Synchronization Impact on Throughput Performance in LTE Network

This paper presents a study of phase synchronization impact on throughput in Long Term Evolution (LTE) network with different transport protocols. Phase synchronization is needed for advanced features in LTE and other precise technologies with minimal clock error of Nano seconds. An End to End LTE testing environment is built by using real User Equipment (UE) and LTE core network for studying the throughput impact due to Phase Synchronization in different transport modes. This experimentation is carried out for comparing the throughput of the system with Frequency Synchronization Mode (FM) and Frequency & Phase synchronization Mode (FPM). A novel study has been conducted on throughput for TCP and UDP traffic in different LTE bandwidths, based on real traffic conditions. The study shows that system performance in Uplink (UL) and Downlink (DL) throughput has improved by using Frequency along with Phase synchronization in LTE network using GPS as a clock source.

Mechanisms of toxicity of particulate engine emissions from diesel and alternative fuels under realistic traffic conditions

Mechanisms of toxicity of particulate engine emissions from diesel and alternative fuels under realistic traffic conditions

Visual Perception by Drivers of the Advertisements Located at Selected Major Routes

This article characterizes the research based on the analysis of the eye fixation points on the advertisements. The research has been realized in real road and traffic conditions. The group of 12 drivers was equipped with the glasses occulometric measurement system mounted on the driver’s head. The participants were driving their private cars. The analysis was concentrated on the fixations on the advertisement tables located along the selected national roads in Rzeszów area (Poland). For better recognition if the advertisements have distracted the drivers the number of fixations on the advertisements has been compared with the fixations on the road signs. The active drivers have observed many visual attractors like advertisements, road signs and cars being ahead and on another lane. Passive drivers have low number of fixations on road signs and advertisements. Their fixations typically have been localized on survey and they probably used the peripheral vision in order to recognition of road sign shapes. The results show, that: the percentage of fixations on the advertisement and road signs is different for each participants; the highest percentage of fixated advertisements was on the section with small number of advertisements, but in the city area, when a group of advertisements was on the road, the participants selected some of them, yet no participant fixated all advertisements localized in a small distance between them; the single advertisement visible from the long distance strongly attracts the visual perception; the percentage of the fixated advertisements was higher than road signs.

Relationship between black carbon (BC) and heavy traffic in São Paulo, Brazil

Black carbon (BC) concentration measurements were performed using a multi-angle absorption photometer (MAAP) in the eastern region of São Paulo city (EACH site) showing the dominance of heavy-duty diesel vehicle (HDV) emissions. The measurements were combined with traffic counts from a main road (the Ayrton Senna highway) that connects the city to the airport (Guarulhos) and to other important cities and estimated dilution rates from current NOX measurements to compute vehicle BC emission factors (EFBC). The BC emissions represented real operating traffic conditions and were distinguished between HDVs and light-duty gasoline-driven vehicles (LDVs). The EFBC were estimated according to the time of day to distinguish between different fleet compositions and source emission contributions as well as driving and meteorological conditions. Estimates of both the HDVs (170±259mgkm−1) and the LDVs (41±63mgkm−1) show that emissions from HDVs (EFBC(HDVs)) are around 4 times those from LDVs (EFBC(LDVs)). EF estimates for HDVs are consistent with measurements given in the literature not, however, with emission factors for LDVs whose values are slightly higher than those given in the studies reviewed. The correct determination of the EFBC, both for diesel and gasoline vehicles, is necessary so as to give complete knowledge of the BC impacts on external costs, such as air quality, climate and environment, to establish ad-hoc transportation policies and mitigation strategies.

Characterizing particulate polycyclic aromatic hydrocarbon emissions from diesel vehicles using a portable emissions measurement system

Particulate polycyclic aromatic hydrocarbons (p-PAHs) emitted from diesel vehicles are of concern because of their significant health impacts. Laboratory tests, road tunnel and roadside experiments have been conducted to measure p-PAH emissions. While providing valuable information, these methods have limited capabilities of characterizing p-PAH emissions either from individual vehicles or under real-world conditions. We employed a portable emissions measurement (PEMS) to measure real-world emission factors of priority p-PAHs for diesel vehicles representative of an array of emission control technologies. The results indicated over 80% reduction in p-PAH emission factors comparing the China V and China II emission standard groups (113 μg kg−1 vs. 733 μg kg−1). The toxicity abatement in terms of Benzo[a]pyrene equivalent emissions was substantial because of the large reductions in highly toxic components. By assessing real traffic conditions, the p-PAH emission factors on freeways were lower than on local roads by 52% ± 24%. A significant correlation (R2~0.85) between the p-PAH and black carbon emissions was identified with a mass ratio of approximately 1/2000. A literature review indicated that diesel p-PAH emission factors varied widely by engine technology, measurement methods and conditions, and the molecular diagnostic ratio method for source apportionment should be used with great caution.

Asphalt wearing course optimization for road traffic noise reduction

Nowadays traffic noise and air pollution are as important as durability parameters, what leads to the need of more comprehensive approach when planning, designing, constructing and maintaining road pavements. Having in mind country differences in traffic volumes, climate conditions and financial capabilities it is not easy to transfer various solutions from country to country. Due to such peculiarities, large research study was initiated in Lithuania seeking to develop efficient and effective low noise pavement solution for specific regional climate conditions. This paper presents research of commonly used asphalt concrete (AC), stone mastic asphalt (SMA), porous asphalt (PA) and a concept of noise reducing asphalt mixtures. As part of this study large scale laboratory testing of acoustical and mechanical performance, durability and resilience to climate were performed. The paper also presents analysis of laboratory testing results which were positive and followed with the pilot implementation of developed asphalt mixtures for further research activities under real traffic and climate conditions.

Vehicle Loads for Assessing the Required Load Capacity Considering the Traffic Environment

The effects of traffic loads on existing bridges are quite different from those of design live loads because of the various traffic environments. However, the bridge maintenance and safety assessment of in-service bridges maintain the design load capacity without considering the current traffic environment. The real traffic conditions on existing bridges may require a load capacity that is considerably different from the design. Therefore, the required load capacity of an existing highway bridge should be determined according to the extreme load effects that the bridge will experience from the actual traffic environment during its remaining service life for more rational maintenance of the infrastructure. A simulation process was developed to determine evaluation vehicle loads for bridge safety assessment based on the extreme load effects that may occur during the remaining service life. Realistic probabilistic traffic models were used to reflect the actual traffic environment. The presented model was used to analyze the extreme load effect on pre-stressed concrete (PSC) and steel box girder bridges, which are typical bridge types. The traffic environmental conditions included the traffic volume (2000–40,000), the proportion of heavy vehicles (15–45%), and the consecutive vehicle traveling patterns. The spans of the sample bridges were 30 m (PSC bridge) and 45 or 60 m (steel box girder bridge). In the results, the extreme load effects tended to increase with either the traffic volume or proportion of heavy vehicles. The evaluation vehicle loads for bridge safety assessment may be adjusted with the traffic conditions, such as the traffic volume, the proportion of heavy vehicles, and the consecutive vehicle traveling patterns.

Forecasting greenhouse gas emissions performance of the future Australian light vehicle traffic fleet

Knowledge of real-world greenhouse gas emission rates for traffic is necessary for forecasting transport greenhouse gas emissions. This paper presents greenhouse gas emission rates that assist forecasting and modelling greenhouse gas emissions from light vehicles, i.e. private passenger vehicles and light commercial vehicles under realistic traffic conditions. It develops confidence intervals for market shares by categories for fuel or energy efficiency on the Australian market for new light vehicles for the period 2016–2030. The model estimates realistic market scenarios by simulating likely variations of capital and running costs of alternatives for car buyers and by considering buyers’ willingness-to-pay for fuel/energy efficiency. The results suggest that market forces will be insufficient to promote battery electric vehicles and plug-in hybrid electric vehicles in Australia. On average the widths of the 95% confidence intervals for greenhouse emission rates are about 10–15% of the magnitudes of the emission rates, so that analysts can forecast transport greenhouse gas emissions with a reasonable level of certainty. The study suggests that policy interventions to accelerate the uptake of low or zero emitting vehicles may be required.

An experiment on rider stability while mounting: Comparing middle-aged and elderly cyclists on pedelecs and conventional bicycles

Pedelecs, popular among elderly cyclists, are associated with a higher injury risk than conventional bicycles. About 17% of these injuries are due to falls while (dis)mounting. Using instrumented bicycles, this study aimed to identify factors contributing to the stability of self-chosen mounting methods in four user groups: 30–45 versus 65+ years of age and males versus females. Mounting stability on pedelecs was compared with that on conventional bicycles, in controlled experimental setting (task in a fenced off parking lot) but also in real traffic conditions (traffic light turns green). Two mounting phases were differentiated: phase 1 as the transition from ‘earth bound’ to ‘balance’ and phase 2 as the acceleration to achieve harmonized cycling. Stability was operationalised in terms of the duration of these phases: the shorter their duration, the higher the stability. Pedelecs were shown to be less stable in phase 1 than conventional bicycles, irrespective of user group. For all user groups, only in phase 2 the advantages of electrical support kicked in. Results obtained in traffic conditions confirmed the patterns obtained in the controlled setting, with as only difference a lower speed in traffic conditions, which held for both mounting phases and bicycle types. Also measures of physical limitations due to low muscle strength were shown only to be compensated for by pedal support in phase 2 and not in phase 1. Further, mounting characteristics affected pedelec stability in phase 1 and not in phase 2. Higher stability was associated with a) starting while seated and b) using the pedal to push off. Although, these mounting characteristics were confounded with age, gender, and muscle strength, the pattern of results still suggest certain mounting techniques to be more beneficial for pedelecs. The results further illustrate the importance of a deeper understanding of the interactions of bicycle types and user groups on critical manoeuvres and their potential contribution to the optimisation of pedelec design and the training of safe mounting techniques.