Rear Of Vehicle Research Articles

Design sensitivity analysis in the kinematics of the 4SS-axle guiding mechanism with Panhard bar

This work deals with the design sensitivity analysis in the kinematics of the vehicle rear axle guided by four points - on four spheres (so called 4SS), with Panhard bar. The geometric parameters that define the kinematic scheme of the axle guiding mechanism are considered in this study, which aims to identify the influence of these parameters on the specific kinematic functions. The purpose is to achieve a separation of geometric parameters depending on their influences on the objective functions to be optimized from a kinematic point of view, so as to simplify the process of effective optimization, by taking into account (as design variables) only the main parameters.

Design approach of heavy goods vehicle underrun protection using morphological analysis

One of the most harmful of two-vehicle crashes to passenger vehicle occupants is when the front of passenger vehicle hits and passes underneath the rear of truck. It resulted in 23% of total death from two-vehicle crashes with a truck in 2018 based on data from the U.S. Department of transportation’s Fatality Analysis Reporting System (FARS). To reduce the violence of such accidents, the rear underrun protective device (RUPD) is installed on the rear of heavy goods vehicle (HGV), to cause the crumple zone of the impacting passenger vehicle absorbing the impact energy and prevent the impacting passenger vehicle from getting crushed under the HGV. This article demonstrates an approach to design the RUPD based on design inputs, including the structural strength, the local RUPD builders, and the variation of commercial HGV types in Thailand. The morphological analysis is applied along with brainstorming among design team, local manufacturers, and government agency, to generate a total of 72 potential RUPD solutions. In this study, three potential RUPD designs were proposed as RUPD prototypes for different HGV types to investigate their structural strength in terms of strain, deformation, and maximum reaction force. The explicit dynamic finite element (FE) method was implemented to accurately simulate the structural strength of the RUPD prototype since its results were validated by the real test of full-scale prototype with reference to the UN R58 standard. From the results, all proposed RUPD prototypes satisfied the UN R58 standard and are not violated by test loads at all relevant positions. In addition, different designs of the protective beam, which was found to be the main load-bearing resstive component of RUPD, were proposed. Their structural strength and energy-absorbing capability were examined by FE simulation to allow local RUPD builders to have alternatives for RUPD fabrication depending on their resources and applications. Besides, the proposed design approach in this study could be further applied as a guideline design for other RUPD types in a commercial scale.

Connected and Automated Vehicle Mixed-traffic Car-following Model Considering States of Multiple Front and Rear Vehicles

Connected and Automated Vehicle Mixed-traffic Car-following Model Considering States of Multiple Front and Rear Vehicles

Optimization Model Design of Regenerative Braking Energy Utilization of Subway Train based on Block Zoning

There are a series of problems such as short distance between urban rail transit stations, large energy consumption, and heat treatment difficulty when trains start and stop. By optimizing the interval time and improving the efficiency of the regenerative braking energy of subway trains, these problems can be solved. In this paper, the primary entry point of the analysis is the condition of “traction -- idling -- braking” in the inter-station block partition. The energy utilization rate of the regenerative brake is calculated by using the overlapping time of the front and rear vehicle traction brakes. The utilization rate of the regenerative braking energy is expressed by the area method. On this basis, a model of 12 operating conditions is established, and the total traction power of train operation minus regenerative braking energy is taken as the objective function, and the train travel time, stop time, departure interval time, and other constraints are taken as constraints, and an optimization model of regenerative braking energy utilization of subway train based on block partition is designed.

Analisa Kerusakan Perkerasan Jalan Aspal

The road Kari Taluk Kuantan Terminal is a cross-road with flexible pavement that has suffered severe damage. The research objective was to find the remaining life of the pavement plan and the degree of damage to the asphalt pavement, using the Bina Marga method. During the service period, the pavement will experience repeated loading which causes damage, especially on the road section of the Terminal Kari Teluk Kuantan, Kuantan Singingi Regency STA 2 + 700 to 4 + 175. The results of the analysis that have been done, that: The remaining life of the pavement for the next 10 years = 12%, with a Truck Factor 0.465 <1, which means that the road is not fit to pass, The degree of damage for light front wheel vehicles is 0.0001, bus 0.0246, Truck 2 as 0.0178. The degree of damage for light vehicle rear wheels is 0.0001, buses 0.1245, Truck 2 as 0.0900, meaning that the average degree of damage for light vehicles and heavy vehicles, is less than one axis, in this case the damage is classified as collapse due to damage, with vehicle load normal which does not really affect the degree of damage to the road.

Aerodynamic drag reduction by means of platooning configurations of light commercial vehicles: A flow field analysis

Platooning configurations of two, three and four commercial vehicles were tested at a Reynolds number based on the vehicle’s length (L) of230000. The platoon configurations were obtained using an instrumented model, and three wooden replicas located at different positions with respect to the instrumented one. The reference model presents a slant angle at the leading edge, which can produce, in principle, a significantly different flow field compared to the generally studied Ahmed body. Drag, static pressure distributions and pressure fluctuations measurements were carried out. Additionally, planar PIV measurements were performed to investigate the near wake of the two-vehicles platoon configuration.For the two-models platoon, drag reductions of 30% and 43% were evidenced for the front and for the rear vehicle, respectively, at an inter-vehicle distance (d) equal to half the vehicle’s length, and corresponding to an average drag reduction of 36.5%. For increasing distance, the benefit associated with the platooning configuration reduces, reaching an average drag reduction of 20% atd/L = 3. We relate the vehicle’s drag to the flow field organization and to the distribution of the modal energy through Proper Orthogonal Decomposition of the microphonic probes located on the base of the instrumented vehicle. We also evidence that the key element that is responsible for the pumping of the wake is the large vortex that generates near the top edge of the vehicle’s base.We show that the slant angle does not affect the drag reduction of the leading vehicle of the platoon, whereas it can lead to larger differences in the case of the rear vehicle.For three and four-vehicles platoons, consistently larger values of the average drag reduction are experienced (≈35%) and were also obtained for distances >1L. A simple model describing the overall drag reduction for a generic number of vehicles is presented and discussed.

Evaluation of Misalignment Effect in Vehicle-to-Vehicle Visible Light Communications: Experimental Demonstration of a 75 Meters Link.

The use of visible light communications technology in communication-based vehicle applications is gaining more and more interest as the research community is constantly overcoming challenge after challenge. In this context, this article addresses the issues associated with the use of Visible Light Communications (VLC) technology in Vehicle-to-Vehicle (V2V) communications, while focusing on two crucial issues. On the one hand, it aims to investigate the achievable communication distance in V2V applications while addressing the least favorable case, namely the one when a standard vehicle rear lighting system is used as a VLC emitter. On the other hand, this article investigates another highly unfavorable use case scenario, i.e., the case when two vehicles are located on adjacent lanes, rather than on the same lane. In order to evaluate the compatibility of the VLC technology with the usage in inter-vehicle communication, a VLC prototype is intensively evaluated in outdoor conditions. The experimental results show a record V2V VLC distance of 75 m, while providing a Bit Error Ratio (BER) of 10−7–10−6. The results also show that the VLC technology is able to provide V2V connectivity even in a situation where the vehicles are located on adjacent lanes, without a major impact on the link performances. Nevertheless, this situation generates an initial no-coverage zone, which is determined by the VLC receiver reception angle, whereas in some cases, vehicle misalignment can generate a BER increase that can go up to two orders of magnitude.

Influence Range and Traffic Risk Analysis of Moving Work Zones on Urban Roads

There is a body of literature on the influence range and traffic risk of fixed work zones. However, relatively few studies have examined the effect of ubiquitous moving operating vehicles, such as road cleaners, on urban roads. The influence of low speed moving work zones on road traffic flow and traffic risk is still unclear. In this work, we used simulations to establish an urban expressway three lanes VISSIM model, and selected the road traffic volume and speed of the moving work zone as the independent variables. We analyzed the range of influence of the moving work zone on the rear vehicles in the left, middle and right lanes of the urban expressway and the traffic risk variation law caused by the moving work zone. The results show that the left lane was indirectly affected by the moving work zone when the traffic volume reached 2000 pcu/h. The influence of the moving work zone on the middle lane was controlled by the traffic volume and the speed of the moving work zone. Both the left and middle lanes were mainly impacted by vehicles changing lane from the right lane. Regardless of the traffic volume and the speed of the moving work zone change, the vehicles 200 m behind a moving work zone will be directly affected in the right lane. Furthermore, the average traffic risk is the highest within 50 m of the moving work zone in the right lane. When the traffic volume decreases and the speed of the moving work zone increases, the average traffic risk decreases gradually. These results provide a scientific basis for the operation and management of moving working vehicles on urban roads.

Introducing a New Apparatus for Designating Two-Lane Highway Passing and No-Passing Zones

Two-lane highways constitute a large proportion of the U.S. highways. An essential component needed in the design of safe two-lane highways is the passing sight distance (PSD). Otherwise, insufficient PSDs lead to passing-related crashes and, therefore, no-passing zones ought to be marked. This research involves the development of a new apparatus of the two-vehicle method, which is used for measuring the PSD in the field. That is to replace the defunct apparatus used by the Wyoming Department of Transportation (WYDOT). To the best of the authors’ knowledge, the introduced apparatus is the most up-to-date system and addresses shortcomings of previous research. The two-vehicle method involves two successive vehicles spaced at a gap, equivalent to PSD, and both vehicles travel at the speed limit. The driver of the rear vehicle operates a switch when the lead vehicle becomes invisible because of sight obstructions, such as vegetation, signaling the beginning point of the no-passing zone. Similarly, the switch is operated when the lead vehicle returns to view to designate the endpoint of the no-passing zone. The apparatus is composed of vehicle-to-vehicle radio communication devices, global positioning system devices, the switch and computers with graphical user interfaces to record and display the data. Testing was conducted on two two-lane highway segments. As per the results, overall discrepancies between WYDOT’s no-passing zone markings and those designated by the apparatus, developed, ranged from 1% to 7%. This research lays the foundation for a future study involving the development of a cutting-edge prototype.

Study on the Effect of Stiffness Matching of Anti-Roll Bar in Front and Rear of Vehicle on the Handling Stability

In order to study the effect of front and rear anti-roll bar’s stiffness on vehicle’s handling stability, the structure and force of the anti-roll bar are analysed, and the vehicle’s rolling model, simplified car motion model and multi-body dynamics model of a car are established. The influence of stiffness change of the anti-roll bar on understeer of the vehicle is studied by constant radius cornering simulation. In swept-sine steering input simulation, the influence of stiffness change of the anti-roll bar on the response indexes of swept-sine steering input simulation are studied, the rule of these indexes changing with stiffness of anti-roll bar is obtained. It is found at high frequencies, due to the damping effect of the system, the influence of stiffness change on yaw rate gain is opposite to that of low frequency. In step steer input simulation, the influence of stiffness change of anti-roll bar on lateral acceleration and transition time are studied. Finally, this paper matches the stiffness of front and rear anti-roll bars of the vehicle based on swept-sine steering input simulation. The results show that the handling stability of the vehicle becomes relatively better after the stiffness of the anti-roll bars is matched.

Analysis and design of fuzzy-based manoeuvring model for mid-vehicle collision avoidance system

This paper offers a fuzzy-based manoeuvring model labeled as Fuzzy-based Midvehicle Collision Avoidance System (FMCAS) resolving two road crash scenarios. The first scenario covers dual situations (a) Mid vehicle collision avoidance with the rear vehicle under no front vehicle condition and (b) Curvilinear path strategy based on real road conditions. While the suitable curvilinear motion to fit the constrained path for parallel parking is the other scenario. Curvilinear fitting strategy on the left and right sides is achieved by the mid (host) vehicle using fuzzy interpolation techniques modeled by FMCAS. Also, the offset-based curvilinear path determined by FMCAS automatically fits the constraint path to avoid vehicle crashes in highly occupied lanes. In this methodology, path constraint is applicable for both scenarios in forward and reverse directions. The appropriate constraint paths estimated using the developed fuzzy-based polynomial fitting addresses the diverse vehicle kinematic issues. Mean square error values of $$3.9443 \times {10}^{-28}$$ m and 0.0148–0.7210 m about the proposed fuzzy respect to crisp and FMCAS are also capable of delivering diverse consequents in highly intact road scenarios. The fuzzy rule base is motivated in this research article to obtain a collision-free environment addressing many collision conditions in the real-time scenario.

Developing a model to determine the number of vehicles lane changing on freeways by Brownian motion method

Abstract Lane change maneuvers are essential on car trips. Drivers change lanes to follow the desired route to reach their destination or improve their driving condition or level of service. To change lanes, a driver must consider several factors that affect safety. Due to the lack of appropriate data and consequently the lack of appropriate models to determine the number of lane-changes on the road (as an influential factor in accidents), this study attempts to collect proper data in a new way. Thus, the Qazvin-Karaj freeway was selected as the case study. After installing the imaging cameras and performing the image processing, SPSS and Expert Design statistical software were used to model development. The Brownian motion model was also used to construct the driver change lane model. The results showed that logarithmic model number 2 reported a better coefficient of determination than other models with a value of 0.472. Then models 3 and 9 were ranked with R 2 of 0.451 and 0.442, respectively. Also, the Expert Design model with R 2 (0.786) could have a better fit. The value of the response variable (Nch + 0.52)0.74 was obtained three-dimensionally against the changes of distance from the front vehicle (Df ) and distance from the rear vehicle (Db ). Variable values of distance from the front car and distance from the rear vehicle have more effective values on the number of lane changes than left and right distance values. The observed and Brownian data had a slight mean difference (0.018), and also, the standard deviation was so small. Also, the correlation in this data pair is 0.912, which is a suitable value and indicates a slight difference between the outputs of the Brownian model and the observations.

An Improved Intelligent Driver Model Considering the Information of Multiple Front and Rear Vehicles

This paper proposes an improved intelligent driver model (IDM) by considering the information of multiple front and rear vehicles to describe the car-following behaviour of CAVs (Connected and autonomous vehicles). The model involves the velocity and acceleration of multiple front and rear vehicles as well as the velocity difference and headway between the host vehicle and its surrounding vehicles. By introducing location-related parameters, the model quantitatively expresses the change in influence degree of a surrounding vehicle with its location to the host vehicle. To maximize traffic stability, we obtain the optimal value of the parameters in the model and the effect of specific time delays on the stability of traffic flow with numerical simulation. The results indicate that for a single vehicle control, the proposed model provides a much quicker and smoother acceleration and deceleration process to the desired speed than the IDM and multi-front IDM. And for fleet control, the proposed multi-front and rear IDM is superior to the other two models in decreasing the starting and braking time and increasing the stability of speed and acceleration. With effective car-following behaviour control, it is helpful to improve the operation efficiency of CAVs and enhance the stability of traffic flow. In addition to the car-following behaviour control, the model can be utilized for fleet control in the case of CAVs’ homogeneous flow. This model can also serve as an effective tool to simulate car-following behaviour, which is beneficial for road traffic management and infrastructure layout in connected environments.

Aerodynamic simulation of optimized vortex generators and rear spoiler for performance vehicles

In today's world, where fuel prices in all modes of transport are skyrocketing, car manufacturers must find better and innovative ways to make their cars more energy efficient. A reduction in fuel consumption of a vehicle directly corresponds to the non- renewable fossil fuels' lesser consumption and a decrease in vehicular pollution. All road vehicles under driving conditions are made to pass through a wall of air around them and displace this air envelope as efficiently as they can depend upon the vehicle's shape and frontal area. As it flows around the car, this air envelope is responsible for drag force, which is the main opposition to the vehicle's forward motion. This drag force is proportional to the square of the velocity of the car and as a result, increases significantly after certain speeds. In most passenger vehicles due to constraints created by cabin space, regulations, etc., the cars end up being somewhat obliquely and boxy shaped, leading to turbulence, particularly towards the rear end of the car. This formation of turbulence results in flow separation at a point near the vehicle's rear windshield, which causes the boundary layer to not adhere to the body surface, expand and create a high-pressure region which induces drag along this portion of the vehicle. When placed at the specific distance upstream of the flow separation point, the vortex generators play a pivotal role in reducing drag and lift. And coupled with a rear wing can give suitable downforce values and drag reduction by redirecting the flow of air at the right angle of approach to the wing and preventing flow separation. The drag reduction is obtained by changing the angle of attack of the airstream with the wing by changing the orientation of vortex generators.

A New Parametric Function-Based Dynamic Lane Changing Trajectory Planning and Simulation Model

Lane-changing (LC) problem may cause serious accidents or create a painful traffic jam at multi-lane roads. Existing LC simulation model was created with some limitations (less fitted, without velocity and acceleration profiles, high curvature) by using well known trajectory curve such as Hyperbolic Tangent Curve (HTC), Sine-Based Curve (SC), Polynomial Curve (PC). In this study, a new parametric curve had been proposed by using curvilinear coordinate system and fitted against Next Generation Simulation (NGSIM) real dataset. Further, new profiles of velocity and acceleration were designed using the proposed LC trajectory curve. The curvature of proposed model was zero-based curvature both at LC starting and ending points. This proposed curvature was compared with two models such as HTC and SC. The average root-mean-square-error of proposed model decreased with 1.84% for left LC and 15.48% for right LC compared to HTC model and 1.74% for left LC and 15.60% for right LC compared to SC model. Similarly, the proposed model for velocity and acceleration profiles improved significantly from PC model. The proposed parametric curve solves the gap and collision points of LC vehicle with a front vehicle and rear vehicle at target lane and can be used in real LC path planning.

A dynamic avoidance mobility model for the following car using naturalistic driving data

With the improvement of automated vehicle technology, it is expected that automated vehicles and Human-driven vehicles will share road traffic for a long time in the future. For some low-speed autonomous driving vehicles (<14km/h), which developed for the elderly, one obvious problem is that if they are driven on public roads for a long time, they will affect the normal traffic flow, reduce the efficiency of traffic, and also cause a decrease in social acceptability. In this paper, we aim to study of avoidance strategy for low-speed automated vehicles to give the way for the approaching rear vehicles, which is expected to avoid the dissatisfaction of the following vehicle as much as possible, and without a large delay in the arrival time of the ego-vehicle. A vehicle deceleration behavior dataset is developed by using the naturalistic trajectory data of human drivers collected on the Urban Streets in the United States, and extract the deceleration behavior of normal drivers when they noticed a slower car ahead and built those data into a new dataset. Based on the regression analysis of the database, we propose a novel dynamic avoidance mobility model for the following car. It can dynamically adjust the timing of avoidance according to the velocity and headway of the following car. The experimental results show that our method can achieve a relatively low delay of the ego-car arrival time while the proportion of the rear driver’s dissatisfaction is kept at a low level

Occupant kinematics in a high speed vehicle-to-vehicle rear-end collision

14.6% of real-world crashes are of 6 o'clock impact orientation, and 72.7% of the involved vehicles are sedans. The risk of serious to fatal injuries in 6 o'clock impacts at 35 mph (56 kph) delta V and over was 7.3%, more than 70 times higher than the crashes under 35 mph. A rear-end vehicle-to-vehicle crash test was conducted using two sedans at 125 kph. The collision resulted in a 66 kph delta V of the struck vehicle. The intruding rear seatback occupied most of the rear seat compartment and pressed against the driver seat which was moving rearward relative to the vehicle. The driver seat and the ATD torso stopped moving rearward, but the head kept moving rearward over the head restraint with the neck in extension. These kinematics were due to the ATD moving upward with respect to the vehicle during the downward movement of the vehicle rear structure.

Importance of Vehicle Body Elements and Rear Axle Elements for Describing Road Booming Noise

For investigating influences of vehicle components on the acoustic comfort at low frequencies, e.g., the booming noise behavior of a vehicle, building a whole car simulation model is useful. To reduce the model’s complexity and to save resources in the validation process, we first identify relevant components before building the model. Based on previous studies, we focus on the vehicle’s body and the rear axle. In this paper, we analyze which axle and body elements are crucial for describing road booming noise. For this purpose, we use impact measurements to examine noise transfer functions of the body and a vibro-acoustical modal analysis to identify coupled modes between the body’s structure and the interior cavity. For investigating relevant force paths from the rear axle to the body, we used a chassis test bench. We identify the main transmission paths of road booming noise and highlight which axle and body components have an influence on them. Mainly the rear axle in its upright direction in combination with a rigid body movement of the rear tailgate coupled with the first longitudinal mode of the airborne cavity causes road booming noise. Furthermore, the rear axle steering, the active roll stabilization and the trim elements of the vehicle’s body are essential to describe road booming noise. The results can be used to set priorities in the validation of individual axle and body components for future simulation models. We found that the ventilation openings, the front seats, the headliner, and the cockpit of a vehicle have little influence on its noise transfer functions from the rear axle connection points to the driver’s ear between 20 and 60 Hz.

Rear-end collision warning of connected automated vehicles based on a novel stochastic local multivehicle optimal velocity model

Studying the rear-end early warning methods of connected automated vehicles (CAVs) is useful for issuing early warnings and reducing traffic accidents. Establishing a corresponding driving model according to CAV characteristics is necessary when designing intelligent decision and control systems, especially for the safety speed threshold. However, since traffic systems are stochastic, there are random factors that influence car-following behavior. Therefore, this study proposes a rear-end collision warning method for CAVs based on a stochastic local multivehicle optimal speed (SLMOV) car-following model. First, the SLMOV model is proposed to characterize the car-following behavior of CAVs. Simultaneously, a stability analysis and parameter estimation method are discussed. Second, the safety distance between the CAVs changes with time because the speed of the rear vehicles satisfies the SLMOV model, which is used to calculate the safety probability of rear-end CAV collisions through an analysis of the driving process. The speed threshold is assessed by controlling the rear-end collision probability. Third, next-generation simulation (NGSIM) data are used in an empirical analysis of a rear-end collision warning method on the basis of a parameter estimation of the SLMOV model. The results present the speed thresholds of vehicles under different braking deceleration levels. Finally, the merits and demerits of fixed-speed and variable-speed adjustment time intervals are compared by considering driving safety and comfort as evaluation indexes. A reasonable CAV adjustment time interval of 0.4 s is determined. This result can be used to help develop a vehicle loading rear-end collision warning system.

REAR SIDE CONSPICUITY OF HEAVY GOOD VEHICLES BASED ON LIGHTING COMPONENTS

In Malaysia, accidents that involve collisions with rigid and articulated trucks are mainly related to the conspicuity issue i.e. the issue of the conspicuity of the lighting components on heavy goods vehicles (HGVs). Thus, visibility and conspicuity must be improved because such an improvement can help drivers encounter safety measures on the psychological phenomenon. Conspicuity is the ability of a vehicle to be noticed without observers intentionally searching for it. In Malaysia, HGVs must be equipped with lighting components for improved visibility. The study aims to analyse the percentages of lighting components that comply with the MS ISO 303:2004. This research is conducted at Jawi Toll Plaza, Nibong Tebal, Pulau Pinang from 9:00 a.m. to 5:00 p.m. Results show that 93% of two-axle box trucks have installed rear lighting components that adhere to the standard. Meanwhile, other categories are between 38% and 91%. In conclusion, even though Heavy Goods Vehicles recorded as having high compliance levels of the rear lighting components, the accident still occurred. The types of crashes are based on the inadequate visibility involved when the moving vehicles are approaching the rear or sides of slow-moving or stationary vehicles at night.