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Passenger fatigue during long distance driving is greatly influenced by the comfort performance of the seat. Seat comfort performance is determined by the appropriate contour of the seat and the appropriate pad with sufficient thickness. The height of vehicle has been lowered to enhance car styling, and battery for electric vehicle applied to the underbody of the vehicle, reducing the package space of the seat in the vehicle. These external factors eventually lead to a reduced pad thickness of the seat cushion and compromise one of the important components in the seat cushion compartment, creating an uncomfortable cushioning problem when driving long distances. To improve the cushion composition of the seat within a limited package, air bladders are applied to the underside of the cushion pad. In addition, the function to support the buttocks using the air bladders of the lower cushion, similar to lumbar support for the back, was implemented to improve cushion comfort performance.

A sliding door is one of the car door systems, which is generally applied to the vans. Compared with swing doors, a sliding door gives comfort to the passengers when they get in or out the car. With an increasing number of the family-scale activities, there followed a huge demand on the vans, which caused growing interests in the convenience technology of the sliding door system. A typical sliding door system has negative effects on the vehicle interior package and the operating effort. Since the door should move backward without touching the car body, the trajectory of the center rail should be a curve. The curve-shaped center rail infiltrates not only the passenger shoulder room, but also the opening flange curve, which results in the interior package loss. Moreover, as the passenger pulls the door outside handle along the normal direction of the door outer skin, the curved rail causes the opening effort loss.

3D digital human modeling (DHM) tools for vehicle packaging facilitate ergonomic design and evaluation based on anthropometry, comfort, and force analysis. It is now possible to quickly predict postures and positions for drivers with selected anthropometry based on ergonomics principles. Despite their powerful visual representation technology for human movements and postures, these tools are still questioned with regard to the validity of the output they provide, especially when predictions are made for different populations. Driving postures and positions of two populations (i.e. North Americans and Koreans) were measured in actual and mock-up SUVs to investigate postural differences and evaluate the results provided by a DHM tool. No difference in driving postures was found between different stature groups within the same population. Between the two populations, however, preferred angles differed for three joints (i.e., ankle, thigh, and hip).

Shudder vibration of a hydraulic power steering system during parking maneuver was studied with numerical and experimental methods. To quantify vibration performance of the system and recognize important stimuli for drivers, a shudder metric was derived by correlation between objective measurements and subjective ratings. A CAE model for steering wheel vibration analysis was developed and compared with measured data. In order to describe steering input dependency of shudder, a new dynamic friction modeling method, in which the magnitude of effective damping is determined by average velocity, was proposed. The developed model was validated using the measured steering wheel acceleration and the pressure change at inlet of the steering gear box. It was shown that the developed model successfully describes major modes by comparing the calculated FRF of the hydraulic system with measured one from the hydraulic excitation test.

Roof racks have become a very popular feature of vehicles as the market demand for SUV's and RV's has increased drastically over the years. Aeolian tone from the cross bars however, could be a source of severe discomfort for the passengers. Both experimental and numerical steps are taken to enhance the understanding of the generation mechanism of the wind noise. A successful reduction of the noise is achieved by imposing asymmetry in the section geometry, which reduces the strength of Karman vortices shed downstream.

The topology optimization made a great success in pure structural design in an actual industrial field. However, a lot of factors interact each other in a actual engineering field in highly complicated manner. The typical conceptual trade-off is that cost and performance, that is, since they are competing factors, one can't improve the specific system without consideration of interaction. The vehicle has lots of competing factors, especially like fuel economy and acceleration performance, mass and stiffness, roominess and cost, short front overhang and crash-worthiness and so on. In addition, they interact each other in a more complicated manner, that is, fuel economy has something to do with not only engine performance but also mass, roominess, stiffness, the length of overhang, trunk volume, etc. So, most of decision-makings have been made by management based on subjective knowledge and experience.

In general, driving performance is developed to meet preference of average customers. But there is no single standardized guideline which can satisfy various driving tastes of all drivers whose gender, cultural background, and age are different. To resolve this issue, automotive companies have introduced drive mode buttons which drivers can manually select from Normal, Eco, and Sport driving modes. Although this multi-mode manual systems is more efficient than single-mode system, it is in a transient state where drivers need to go through troubles of frequently selecting their preferred drive mode in volatile driving situations It is also doubtful whether the three-categorized driving mode can meet complex needs of drivers.. In order to settle these matters, it is necessary to analyze individual driving style automatically and to provide customized driving performance service in real time.

Conventional EPS (Electric Power Steering) systems are operated by one type of steering tuning map set by steering test drivers before being released to customers. That is, the steering efforts can't change in many different driving conditions such as road conditions (low mu, high mu and unpaved roads) or some specific driving conditions (sudden stopping, entering into EPS failure modes and full accelerating). Those conditions can't give drivers consistent steering efforts. This paper approached the new concept technology detecting those conditions by using vehicle and EPS sensors such as tire wheel speeds, vehicle speed, steering angle, steering torque, steering speed and so on. After detecting those conditions and judging what the best steering efforts for safe vehicle driving are, EPS systems automatically can be changed with the steering friction level and selection of steering optimized mapping on several conditions.

In general, the ride and handling characteristics of a vehicle are strongly dependent on chassis parameters that come from the kinematic and compliance properties of a suspension system. For ride comfort improvement of a compact SUV with increasing handling performance simultaneously, this research proposes a new quantitative approach by considering various driving maneuvers and road surfaces. Particularly, five different road surfaces were used for ride comfort analysis, and this analysis was performed for two different vehicle speeds on a cleat road profile and three different vehicle speeds on a rough road profile. The contribution analysis of a suspension and a seat structure to ride comfort was investigated in order to decide an optimal structural combination. It was shown that contribution of each factor is different according to road profiles and driving conditions respectively.

Professional bus drivers are highly exposed to physical fatigue and work-related injuries because driving task includes complicated actions that require a variety of ability and cause extreme concentration or strain. For this reason, there has always been some sense of concern regarding driver fatigue, especially for drivers of commercial vehicles. In this study, we have tried to analyze quantitative fatigue degree of urban bus drivers by measuring their physiological signals. The investigation is made up of the following approaches: a traditional questionnaire survey and video-ethnographic method with 4-way cameras. The close-circuit cameras are installed to observe the upper and lower body of real drivers when they are in driving or even resting. This approach can help to understand urban bus drivers' behaviors and fatigue-related issues. Based on the video-ethnographic investigation results above, we have got certain patterns of drivers.

Hyundai Kia Motors started developing the under-floor of YF sonata, the base platform for mid-to-large size sedans, in order to reduce weight and improve body performance. For local dynamic rigidity, there are design improvement and additional support structures at suspension mounting area. The strength at the joint where longitudinal and transverse members meet is increased to improve the overall body stiffness, and also the riding comfort and handling. Impact performance and safety is also improved by straightening the major structural members and strengthening the joint areas, efficiently absorbing and inducing the impact energy through load paths. As the body of a vehicle is the constitution of numerous parts, increased strength at the joints and major structural members with more linear profiles have played crucial roles in the improvement in overall body performance.

This paper summarizes the development of a wireless message from infrastructure-to-vehicle (I2V) for safety applications based on Dedicated Short-Range Communications (DSRC) under a cooperative agreement between the Crash Avoidance Metrics Partners LLC (CAMP) and the Federal Highway Administration (FHWA). During the development of the Curve Speed Warning (CSW) and Reduced Speed Zone Warning with Lane Closure (RSZW/LC) safety applications [1], the Basic Information Message (BIM) was developed to wirelessly transmit infrastructure-centric information. The Traveler Information Message (TIM) structure, as described in the SAE J2735, provides a mechanism for the infrastructure to issue and display in-vehicle signage of various types of advisory and road sign information. This approach, though effective in communicating traffic advisories, is limited by the type of information that can be broadcast from infrastructures.

Suspension is a system which operates dynamically according to road condition unlike other system statically mounted to the body. Especially this is more remarkable in high performance vehicle because there are more high inputs from road to suspension than normal vehicle. For this reason, the tightening torque of suspension system of high performance vehicle is more important than other systems and normal vehicle. To support the clamping between parts against force from road when cornering, optimized tightening torque is required to maximize R&H performance. For this optimization, it should be conducted first to comprehend how much performance effects on vehicle by tightening torque. This paper presents relationship between tightening torque of suspension parts hardware and R&H performance.

Today, many automakers are using LED lamp sources in exterior lamps to establish brand awareness and introduce specialized lamp designs. These eye-catching LED lamp source solutions require many control functions as the lamp functions are diversified and advanced, and accordingly the requirements for standardization and optimization of controllers are increasing. In particular, our LED rear combination lamps have a variety of LED loads according to the design of the lamp model, the installation position, and the diagnostic regulations, so that the design complexity and the number of specifications of the controller are increased [4]. In recent years, more and more aesthetic designs and new technologies are used by various automakers to optimize their controllers in cooperation with global partners to optimize costs [1].

In order to utilize in-vehicle systems efficiently, many vehicles are becoming equipped with integrated controls near the center fascia or the control box. However, the placement of these control systems can cause safety issues and risks due to visual distractions. In this study, we proposed a new integrated touch screen on the steering wheel. For this experiment, a control system was placed on the steering wheel or the center fascia. 15 participants were required to drive while utilizing vent and navigation control tasks regarding four different locations. Three of these locations were based on the steering wheel (center, upper right, lower right) and one location on the center fascia. Afterwards, the task completion time and visual distraction rate of the different locations were measured and compared. The results showed that a touch screen placed on the upper right section of the steering wheel had better performance and lower user discomfort.

This study was conducted to develop and validate a multidimensional measure of shift quality as perceived by drivers during kick-down shift events for automatic transmission vehicles. As part of the first study, a survey was conducted among common drivers to identify primary factors used to describe subjective gear-shifting qualities. A factor analysis on the survey data revealed four semantic subdimensions. These subdimensions include responsiveness, smoothness, unperceivable, and strength. Based on the four descriptive terms, a measure with semantic scales on each subdimension was developed and used in an experiment as the second study. Twelve participants drove and evaluated five vehicles with different gear shifting patterns. Participants were asked to make kick-down events with two different driving intentions (mild vs. sporty) across three different speeds on actual roadway (local streets and highway).

In order to perform the Optimal Route Planning avoiding traffic congestion, the structural elements (Rode type, Link type, Facilities type, Lane number, Turning type) in digital map and real-time traffic information are required. However, subjectively tuned cost weights of these elements, non theoretical relationship, and partially supported real-time traffic information that are mostly used for this implementation are not enough to satisfy. Therefore, in this research, by analyzing the relationship between the previously acquired traffic information history for some period of time and elements in digital map, we introduce the reasonable traffic information model that makes to estimate the speed information. Including the estimated speed, all the important factors of map database and the driver's preference, finally we made the cost model.

This paper introduces newly developed suspension system for the all-new SantaFe model of Hyundai Motor Company which will be on the market this year. The new suspension of the all-new SantaFe has been developed to give better handling and driving confidence to a driver compared to the previous model while maintaining a good ride experience. To achieve these targets, the suspension has been fully changed and finely adjusted. The compliance characteristics have been contrasted to those of the previous model. Also, the crash performance and package efficiency which are related to suspension layout has been considered without limitation of suspension performance. Based on the customer’s voice of market, the suspension of the newly developed SantaFe has tried to fit the various customer’s demands.

In this study it will show, big data analysis and user survey of driving records were conducted to investigate frequency of use and ease of operation of the regen paddle to control one-pedal driving system in electric vehicle. According to 3.8 million driving record big data analysis result, it was found that the driver manipulates 3.31 times on average during a single trip, mainly during the early stages of driving. According to user observation research result in 41.8% of participants did not used or used less than 5 time of regen paddle during one single trip. Also 336 participants, which occupy 83%, responded that the regen paddle manipulation for one-pedal driving was inconvenient. In conclusion, because of the use frequency of the regen paddle is low and the operation of regen paddle is inconvenient. It seems necessary to change the design of the regen paddle.

Bad weather conditions such as torrential rain, heavy snow, and thick fog frequently occur worldwide. Vehicle accidents in such bad weather conditions account for a significant portion of all vehicle accidents, and the level of damage is relatively severe compared to other accidents that occur in clear weather. This paper analyzes the driver's driving stability in bad weather conditions, which has such a significant meaning, in various ways through experiments on the inconvenience experienced by the driver. In this study, three levels of bad weather conditions were implemented in a driving simulator environment to evaluate driver inconvenience for six activities. Through driving experiment, quantitative bio-signals and vehicle signals were analyzed in each weather condition. The SD survey was used to assess the driver's inconvenience level for activities performed while driving and analyze the ranking of inconvenience.