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Our objective in this contribution is to categorize driver behavior in terms of preturning maneuvers. We analyze driving behavior in an urban environment prior to turns using data obtained from the CANbus of an instrumented vehicle during a one-hour driving period for 12 different individuals. CANbus data streams such as vehicle speed, gas pedal pressure, brake pedal pressure, steering wheel angle, and acceleration are collected and analyzed for 5, 10, and 15 seconds of driving prior to each turn. We consider all turns for each driver and extract statistical features from the signals and use cluster analysis to categorize drivers into groups reflecting different driving styles. The results show that using this approach we can effectively cluster drivers into two groups. The results show consistency in the membership within a cluster throughout the different timeframes. We conclude that driver behavior classification from such data streams is possible and we hope in the near future to devise driver descriptors that include additional maneuvers. [ABSTRACT FROM AUTHOR]

The lunar surface is a complicated and unknown terrain, and hence, astronauts must be trained to travel on that surface by using a prototype vehicle on the Earth's terrain. However, the gravity of the Earth is six times that of the Moon; thus, the acceleration of a prototype vehicle on the Earth will differ from that of a manned lunar rover on the Moon, when the same acceleration handling input is provided. To obtain the same acceleration in the prototype vehicle on the Earth as that obtained on the Moon, an imitation handling ratio describing the relationship between the acceleration handling input and the wheel rolling speed is proposed in order to replicate the lunar gravitational conditions on the Earth. First, a whole-vehicle acceleration model was established based on the mechanical model of a deformable wheel with a mesh surface. Thereby an acceleration imitation algorithm was derived. A prototype vehicle for use on the Earth is proposed for the purpose of imitating the manned lunar rover under four different vehicle conditions. Fitted functions were used in order to obtain the imitation handling ratio. Finally, experiments were conducted to verify the imitation method; the results revealed that the prototype vehicle on the Earth could effectively approximate the same accelerations experienced by a manned lunar rover, when equivalent acceleration handling inputs were provided. [ABSTRACT FROM AUTHOR]

Crash-based safety performance functions (SPFs) typically cannot account for all design and operational factors that contribute to crash frequency in assessing the safety impacts of these factors. An approach using surrogate safety measures can address this issue, providing these measures can be linked to crashes. This approach was explored by using microsimulation to generate and analyze conflicts for merge areas on Ontario freeways. Crash-conflict integrated SPFs with different time to collision thresholds were then developed and compared. The results of the conflict-based SPFs are in agreement with those from crash-based SPFs developed for the same sample, with logically negative coefficients for acceleration lane length and positive coefficients for traffic volumes. This suggests that the crash-conflict approach is a reasonable substitute for conventional crash prediction models in assessing the safety effects of design changes, especially for those changes that cannot be captured in the conventional models. [ABSTRACT FROM AUTHOR]

Objective: To lay the basis of studying autonomous driving comfort using driving simulators, we assessed the behavioral validity of two moving-base simulator configurations by contrasting them with a test-track setting.Background: With increasing level of automation, driving comfort becomes increasingly important. Simulators provide a safe environment to study perceived comfort in autonomous driving. To date, however, no studies were conducted in relation to comfort in autonomous driving to determine the extent to which results from simulator studies can be transferred to on-road driving conditions.Method: Participants ( N = 72) experienced six differently parameterized lane-change and deceleration maneuvers and subsequently rated the comfort of each scenario. One group of participants experienced the maneuvers on a test-track setting, whereas two other groups experienced them in one of two moving-base simulator configurations.Results: We could demonstrate relative and absolute validity for one of the two simulator configurations. Subsequent analyses revealed that the validity of the simulator highly depends on the parameterization of the motion system.Conclusion: Moving-base simulation can be a useful research tool to study driving comfort in autonomous vehicles. However, our results point at a preference for subunity scaling factors for both lateral and longitudinal motion cues, which might be explained by an underestimation of speed in virtual environments.Application: In line with previous studies, we recommend lateral- and longitudinal-motion scaling factors of approximately 50% to 60% in order to obtain valid results for both active and passive driving tasks. [ABSTRACT FROM AUTHOR]

Most existing fuel consumption models are based on steady-state fuel mapping. However, these models cannot provide satisfactory predictions for vehicles operating under transient conditions. Consequently, a new transient model that can precisely predict fuel consumption under steady-state and transient conditions was developed on the basis of the steady-state model. This new model is characterised by two sub-modules: the steady-state module whose inputs are engine speed and torque, and the transient correction module whose inputs are vehicle speed and acceleration. Vehicle Specific Power ( VSP ) was introduced as a filter to help develop different correction factors for positive and negative VSP . The Argonne National Laboratory’s measurements of different driving cycles including the steady-state cycle, the UDDS cycle, the Highway cycle and the US06 cycle were used to develop the new model. According to the results of this study, the prediction accuracy of fuel consumption models can be improved significantly by introducing transient corrections. The Mean Absolute Percentage Error ( MAPE ) between the predicted and measured fuel consumption decreased from approximately 58% for the steady-state model alone to approximately 23.5% when the transient correction module was introduced. Moreover, this new model performs better than the VT-Micro model. The MAPE values of the new transient models were approximately 2.7–4.6% lower than that of the VT-Micro model. [ABSTRACT FROM AUTHOR]

In the past decades, many improved car-following models based on the full velocity difference (FVD) model have been developed. But these models do not consider the acceleration of leading vehicle. Some of them consider individual anticipation behavior of drivers, but they either do not quantitatively determine the types of driving or artificially divide the driving types rather than deriving them from actual traffic data. In this paper, driver's driving styles are firstly categorized based on actual traffic data via data mining and clustering algorithm. Secondly, a new car-following model based on FVD model is developed, taking into account individual anticipation effects and the acceleration of leading vehicle. The effect of driving characteristics and leading vehicle's acceleration on car-following behavior is further analyzed via numerical simulation. The results show that considering the acceleration of preceding vehicle in the model improves the stability of traffic flow and different driving characteristics have different influence on the stability of traffic flow. [ABSTRACT FROM AUTHOR]

Objective: Two experiments were conducted to determine whether detection of the onset of a lead car's deceleration and judgments of its time to contact (TTC) were affected by the presence of vehicles in lanes adjacent to the lead car.Background: In a previous study, TTC judgments of an approaching object by a stationary observer were influenced by an adjacent task-irrelevant approaching object. The implication is that vehicles in lanes adjacent to a lead car could influence a driver's ability to detect the lead car's deceleration and to make judgments of its TTC.Method: Displays simulated car-following scenes in which two vehicles in adjacent lanes were either present or absent. Participants were instructed to respond as soon as the lead car decelerated (Experiment 1) or when they thought their car would hit the decelerating lead car (Experiment 2).Results: The presence of adjacent vehicles did not affect response time to detect deceleration of a lead car but did affect the signal detection theory measure of sensitivity d' and the number of missed deceleration events. Judgments of the lead car's TTC were shorter when adjacent vehicles were present and decelerated early than when adjacent vehicles were absent.Conclusion: The presence of vehicles in nearby lanes can affect a driver's ability to detect a lead car's deceleration and to make subsequent judgments of its TTC.Application: Results suggest that nearby traffic can affect a driver's ability to accurately judge a lead car's motion in situations that pose risk for rear-end collisions. [ABSTRACT FROM AUTHOR]

Rear-end collisions have been estimated to account for 20–30% of all crashes, and about 10% of all fatal crashes. A thorough investigation of drivers’ collision avoidance behaviors when exposed to rear end collision risks is needed to help guide the development of effective countermeasures. Urgency or criticality of the situation affects drivers’ collision behavior, but has not been systematically investigated. A high fidelity driving simulator was used to examine the effects of differing levels of situational urgency on drivers’ collision avoidance behaviors. Drivers’ braking and steering decisions, perception response times, throttle release response times, throttle to brake transition times, brake delays, maximum brake pedal pressures and peak decelerations were recorded under lead vehicle decelerations of 0.3 g, 0.5 g, and 0.75 g and under headways of 1.5 s and 2.5 s. Results showed (1) as situational urgency increased, drivers released the accelerator and braked to maximum more quickly; (2) the transition time between initial throttle release and brake initiation was not affected by situational urgency; (3) at low situational urgency, multi-stage braking behavior led to longer delays from brake initiation to full braking. These findings show that effects of situational urgency on drivers’ response times, braking delays, and braking intensity should be considered when developing forward collision warnings systems. [ABSTRACT FROM AUTHOR]

This paper describes an integrated chassis control (ICC) algorithm of differential braking, front/rear traction torque, and active roll moment control. The integrated control algorithm is designed to maximize driving velocity and enhance vehicle lateral stability in cornering. The target longitudinal acceleration is determined based on the driver's intention and vehicle current status to ensure vehicle lateral stability in high-speed maneuvering. An optimization-based control allocation strategy is used to distribute the actuator control inputs optimally under consideration of tire and vehicle limitations. Closed-loop simulations of a driver–vehicle–controller system were conducted to investigate the performance of the proposed control algorithm. The performance of the ICC has been compared with those of individual chassis control systems, such as electronic stability control, four-wheel drive (4WD), and active roll control system. The simulation results show that the proposed ICC algorithm improves the performance in high-speed cornering with respect to driving speed without losing stability, compared with individual chassis control systems. [ABSTRACT FROM PUBLISHER]

The high energy consumption associated with acceleration requires electric vehicles (EVs) to accelerate to a chosen speed optimally, particularly in urban driving cycles. Existing methods deal with the minimization of acceleration energy without considering the acceleration duration. This paper focuses on solving a multiobjective optimization problem (MOOP) with two conflicting objectives: minimization of acceleration duration and minimization of energy consumption. Two approaches were used to reach a desired speed: using a single acceleration value and using multiple acceleration values. For each approach, demonstrative speed changes were chosen, and the problem was solved using multiobjective genetic algorithms (MOGAs). The results (Pareto-optimal fronts) obtained by these two approaches were compared using suitable performance metrics. To validate the reliability of MOGA results, statistical analysis was carried out. Furthermore, a nonparametric study, i.e., the Wilcoxon signed-rank test, was conducted to compare the effectiveness of both approaches. It was found that multiple accelerations were more effective in minimizing the duration and energy consumption than a single acceleration. For the same duration, multiple accelerations reduced energy consumption by up to 2%. Sensitivity analysis for both approaches with electric motor model parameters was conducted. The simulation results of EV acceleration using the preferred optimal solution based on driving comfort and the Pareto front's knee suggested a strong implication toward driving assistance. [ABSTRACT FROM PUBLISHER]

In this paper, the energy consumption per distance of a battery electric vehicle (BEV) is comprehensively investigated for various official and gathered real-world drive cycles, including the powertrain's cycle average efficiency. The powertrain component losses are modeled with a high level of detail, and they are functions of both speed and load. It is shown that the difference in calculated drive-cycle energy consumption may be up to 16% when using two different acceleration approximation methods and one speed sample per second, which is an interval commonly used among drive cycles. In contrast to combustion engine vehicles (CEVs), BEV energy consumption per distance generally increases with increasing cycle speed levels, and time spent at high speed levels have the largest influence on the consumption. The effect of acceleration on energy consumption is seen to be considerably reduced due to regenerative braking as it reduces the consumption by up to 49% on an acceleration intense cycle. Even when the regenerative area is limited to about half, the decrease in driving range is less than 1% for most cycles. By introducing the concept of overconsumption, it is shown that much time spent at high levels of acceleration is one of the largest contributors to excess energy consumption for BEVs. Furthermore, the found cycle average powertrain efficiencies are quite similar between the different cycles, with 82%–90% during propulsion and only slightly lower during braking, i.e., much less speed dependent than for CEVs. [ABSTRACT FROM PUBLISHER]

Based on the cellular automata model, a meticulous two-lane cellular automata model is proposed, in which the driving behavior difference and the difference of vehicles’ accelerations between the moving state and the starting state are taken into account. Furthermore the vehicles’ motion is refined by using the small cell of one meter long. Then accompanied by coming up with a traffic management measure, a two-lane highway traffic model containing a work zone is presented, in which the road is divided into normal area, merging area and work zone. The vehicles in different areas move forward according to different lane changing rules and position updating rules. After simulation it is found that when the density is small the cluster length in front of the work zone increases with the decrease of the merging probability. Then the suitable merging length and the appropriate speed limit value are recommended. The simulation result in the form of the speed–flow diagram is in good agreement with the empirical data. It indicates that the presented model is efficient and can partially reflect the real traffic. The results may be meaningful for traffic optimization and road construction management. [ABSTRACT FROM AUTHOR]

This research developed an eco-driving feedback system based on a driving simulator to support eco-driving training. This support system could provide both dynamic and static feedback to improve drivers’ eco-driving behavior. In the process of driving, drivers could get voice prompts (e.g., please avoid accelerating rapidly) once non-eco-driving behavior appeared, and also could see the real-time CO 2 emissions curves. After driving, drivers could receive an eco-driving evaluation report including their fuel consumption rank, potential of fuel saving and driving advice corresponding to their driving behavior. In this support system, five items of non-eco-driving behavior (i.e., quick accelerate, rapid decelerate, engine revolutions at a high level, too fast or unstable speed on freeways and idling for a longer time) were defined and could be detected. To validate this support system’s effectiveness in reducing fuel consumption and emissions, 22 participants were recruited and three driving tests were conducted, first without using the support system, then static feedback and then dynamic feedback utilized respectively. A reduction of 5.37% for CO 2 emissions and 5.45% for fuel consumption was obtained. The results indicated that the developed eco-driving support system was an effective training tool to improve drivers’ eco-driving behavior in reducing emissions and fuel consumption. [ABSTRACT FROM AUTHOR]

To evaluate the impacts of new influence factor in cooperative adaptive cruise control strategy on the dynamic characteristics of traffic flow, an improved cooperative car-following model considering multiple vehicular gap changes with memory is developed to study the influences of multiple vehicular gap changes with memory on each car’s speed, acceleration and relative distance. Some numerical simulations are carried out and the results show that considering multiple vehicular gap changes with memory in designing the cooperative adaptive cruise control strategy can improve the stability of traffic flow and reduce the accidental probability. [ABSTRACT FROM AUTHOR]

In this article, a new approach to estimate the vehicle tyre forces, tyre–road maximum friction coefficient, and slip slope is presented. Contrary to the majority of the previous work on this subject, a new tyre model for the estimation of the tyre–road interface characterisation is proposed. First, the tyre model is built and compared with those of Pacejka, Dugoff, and one other tyre model. Then, based on a vehicle model that uses four degrees of freedom, an extended Kalman filter (EKF) method is designed to estimate the vehicle motion and tyre forces. The shortcomings of force estimation are discussed in this article. Based on the proposed tyre model and the improved force measurements, another EKF is implemented to estimate the tyre model parameters, including the maximum friction coefficient, slip slope, etc. The tyre forces are accurately obtained simultaneously. Finally, very promising results have been achieved for pure acceleration/braking for varying road conditions, both in pure steering and combined manoeuvre simulations. [ABSTRACT FROM PUBLISHER]

This paper presents a MILP (Mixed Integer Linear Programming) model to calculate and manage optimized trajectories of intelligent vehicles in a segment of highway. The objective is to reduce travel time for each vehicle while meeting velocity/acceleration constraints and avoiding collisions. The proposed model considers the main elements of a traffic system, such as topography of lanes, traffic rules and individual capacity of acceleration. It can deals with most traffic situations such as overtaking, obstacles, slopes, and speed reducers. The model uses centralized decision approach which guarantees optimal solution. Although the model cannot be used in a real time application due to high complexity, the optimal result provided can be used as a reference to evaluate the efficiency of other solutions. In this sense, a performance metric for microscopic traffic assessment is proposed. In order to provide a solution for a real time application, a heuristic algorithm is also proposed. Moreover, unlike previous approaches, we explain how individual priority can be respected when trajectories are computed. Several tests are carried out to validate both MILP model and the algorithm. [ABSTRACT FROM AUTHOR]

Effective method for analyzing of the terrain vehicle suspension performance is presented. The key objective of this approach is to make quick analyses of the vehicle suspension system performance. The vehicle is simplified by mathematical modeling of a quarter of it and equations of motion are solved by using Matlab software. To verify the reliability of the proposed method a comparison with one of the simply commercial software is done. The usefulness of the proposed method on the real terrain vehicle is presented in order to analyze the sensitivity of the several suspension parameters such as spring stiffness coefficient, damping coefficient, tire stiffness coefficient, sprung and un-sprung masses. The sensitivity of the suspension parameters is determined by considering of the vehicle body acceleration, vertical tire force and suspension travel that directly influences on the driving comfort and driving safety. [ABSTRACT FROM AUTHOR]

In this study the author develop a practically stable switched non-linear observer bank for simultaneously estimating the vehicle sideslip angle and the road friction coefficient. Each individual non-linear state estimator in the observer bank is based on a non-linear lateral dynamics vehicle model that is parametrised with a distinct road friction coefficient. The inputs to the non-linear observers are typical signals that are available within lateral stability control systems, which include the vehicle speed, steer angle, lateral acceleration and the yaw rate. The authors show that the suggested non-linear state estimator is practically stable under arbitrary switching. Finally, the authors provide numerical simulations to demonstrate the efficacy of our switched non-linear observer design technique. [ABSTRACT FROM AUTHOR]

Previously, we developed a new control concept called 'G-Vectoring control (GVC)' to improve vehicle agility and stability. GVC is an automatic longitudinal acceleration control method that responds to vehicle lateral jerk caused by a driver's steering manoeuvres. In this paper, we compare GVC with the well-known direct yaw-moment control (DYC) method for daily driving ranges in particular. GVC shows good manoeuvrability (i.e. enhances both yawing and lateral acceleration) performance while maintaining a natural yaw and roll feeling in the early stage of cornering, while DYC is effective in improving vehicle stability during large lateral motions. We also re-review our previously proposed 'hybrid control' method that combines the strengths of GVC and DYC. A side-by-side test carried Out for the hybrid control method and DYC only confirms the effectiveness of the hybrid control method. [ABSTRACT FROM AUTHOR]

For ensuring the reliability of automotive electronic accelerator pedal, an accelerator pedal position control model is established, in which the pedal position signal is filtered and diagnosed and through the diagnosis of sensor fault and the selection and calibration of sensor signal, the accurate position of accelerator pedal is finally obtained. By means of simulation and rapid control prototyping, the reliability of whole control process is tested and the results show that the control scheme can meet the requirements of the reliability control for automotive electronic accelerator pedal. [ABSTRACT FROM AUTHOR]

An in-wheel motor drive system is designed for the land driving of multi-domain vehicle. A vehicle model is set up based on the in-wheel drive system and the drive control method is studied. On the basis of the theoretical analysis on steering dynamics, a multi-body dynamic model for vehicle is established with ADAMS. The driving and steering control strategies are proposed and the control model is developed with Matlab/Simulink. By using co-simulation scheme the driving performances of vehicle in typical working conditions including accelerating, steering and braking are validated. The results show that the basic performances of vehicle meet the expected objectives and the driving control strategy is effective. [ABSTRACT FROM AUTHOR]

An adaptive cruise control algorithm is proposed for electric vehicles to coordinate both its economy and safety. The effects of acceleration on the economy of electric vehicles are quantitatively analyzed and the performance indicators for both fuel economy and tracking safety are established. Model predictive control technique is adopted to conduct coordinated optimization on the performance indicators of the system. The results of both simulations and tests indicate that the algorithm proposed can effectively coordinate both economy and safety of electric vehicles. [ABSTRACT FROM AUTHOR]

For tackling the problem of the reduction in longitudinal driving torque and acceleration as well as the occurrence of undesired yaw moment and yaw angular velocity when the driving force control system of distributed drive electric vehicle enters the working mode of acceleration slip regulation, two multi-wheel driving torque coordination control strategies are proposed. Among them the strategy for power performance is aiming at raising longitudinal driving torque and acceleration, while the strategy for stability is targeted at enhancing the lateral stability of vehicle. The results of real vehicle test show that the proposed coordination control scheme effectively achieves the design objectives and improves the performance of vehicle. [ABSTRACT FROM AUTHOR]

Abstract: We study the traffic behavior when a vehicle changes from the first lane to the second lane on a two-lane highway. The incoming vehicle decelerates or accelerates by interacting with the vehicle ahead or behind on the second lane. We apply the extended optimal velocity model to the vehicular motion to take into account the velocity difference. We investigate whether or not the incoming vehicle collides with the vehicles ahead or behind. We derive such conditions that the incoming vehicle comes into collision with the vehicles ahead or behind. The safety–collision transition occurs by changing the lane. The dynamic transition depends highly on the headway, the vehicular speed, the sensitivity, and the velocity difference. We present the phase diagram (or region map) for the safety–collision transition. [Copyright &y& Elsevier]

This paper details the design and validation of an improved cable-type accelerator control system for left hand drive (LHD) army vehicles. A slider mechanism is used for the pedal control unit. The design is verified by kinematic analysis using ADAMS simulation. The vehicle performance and verification of ergonomic parameters are tested using a prototype vehicle. Improvements in the ergonomics, system reliability and packaging/installation in comparison with the existing accelerator control system are demonstrated. [ABSTRACT FROM AUTHOR]

The article presents a reprint of the article "The NUS FSAE Race Car Project" which appeared in the May 18, 2015 issue of the periodical NUS News. Topics discussed include the National University of Singapore (NUS) Formula Society of Automotive Engineering (FSAE) race car project in which mechanical engineering students construct a race car, the FSAE intervarsity race car competition, and the assessment of several aspects of the car such as the race car design, fuel economy, and acceleration.