Earticle

PURPOSES : This study analyzed the difference in a driver's workload between using a driving simulator and field driving in tunnel, highway. METHODS : Based on the literature review, it was found that a driver's workload could be quantified using biosignals. This study analyzed the biosignal data of 30 participants using data collected while they were using a driving simulator and during a field test involving tunnel driving. Relative energy parameter was used for biosignal analysis. RESULTS : The driver's workload was different between the driving simulator and field driving in tunnels, highway. Compared with the driving simulator test, the driver's workload exhibited high value in field driving. This result was significant at the 0.05 level. The same result was observed before the tunnel entrance section and 200 m after the entrance section. CONCLUSIONS : This study demonstrates the driving simulator effect that drivers feel safer and more comfortable using a driving simulator than during a field test. Future studies should be designed considering the result of this study, age, type of simulator, study site and so on.

본 연구에서는 운전자 277명을 대상으로 주관적 운전부하에 영향을 미치는 운전자의 특정 성격 및 태도를 파악하고자 하였다. 조사참가자의 성격과 태도를 파악하기 위해 운전행동결정요인과 운전확신수준 질문지를 이용하였으며, 이들의 주관적 운전부하 수준을 파악하기 위해 NASA-TLX와 DALI를 이용하였다. 연구결과, 기존에 구성된 운전행동결정요인과 운전확신수준의 각 하위 요인들 중 운전행동결정요인의 관계적응성부족과 상황불안 요인, 운전확신수준의 상황둔감성과 주의집중소홀 요인이 주관적 운전부하와 유의한 상관관계를 가지는 요인인 것으로 나타났다. 본 연구에서는 주관적 운전부하와 관련한 운전자 성격 및 태도 요인을 새로이 구성하고자, 운전행동결정요인과 운전확신수준 질문지의 문항들을 이용하였다. 문항들 가운데 주관적 운전부하와 유의한 상관관계를 가지면서, 적절한 내적 신뢰도를 보인 29개의 문항을 최종적으로 추출하였으며, 이 문항들로 요인분석을 실시한 결과, 29개의 문항들을 도로환경 부적응성, 운전자위험성향, 인적환경 부적응성 요인으로 구분할 수 있었다. 이 세 요인들 가운데 운전자 위험성향 요인과 인적환경 부적응성 요인은 DALI로 측정한 주관적 운전부하 수준에 대해 유의한 설명력을 가지는 것으로 나타났으며, 도로환경 부적응성 요인은 NASA-TLX로 측정한 주관적 운전부하 점수에 대해 유의한 설명력을 가지는 것으로 나타났다. 이러한 결과를 통해 운전부하에 대한 예방책을 마련하고, 심리적 특성을 고려한 주관적 운전부하 예측 도구를 개발하는 데 유용한 정보를 제공할 수 있을 것으로 기대하였다.

We are concerned with the fact that workload can reduce a person’s ability to drive safely, thereby potentially causing serious traffic accidents. As such, we performed this study to determine which factors significantly effect a driver’s subjective workload. We used the Driving Behavior Determinants, Driving Confidence Level Questionnaire, subjective workload assessment tools(NASA-TLX, DALI(Driving Activity Load Index)). A total of 227 drivers, with an average age of 35 and average driving experience of 9 years, were asked to complete the questionnaires. Many researchers have utilized the Driving Behavior Determinants and Driving Confidence Level Questionnaire as tools for elucidating driver characteristics. Additionally, the factors examined by these tools have been demonstrated in several studies to have an influence on a person’s driving behavior such as speed. The NASA-TLX and DALI are also known as self-assessment tools for subjective workload. We conducted a correlation analysis between Driving Behavior Determinants and Driving Confidence Level and driver’s subjective workload level. The results indicated that ‘Lack of Interpersonal Adaptability’ and ‘Insensibility’ had a significant correlation with a driver’s subjective workload. We also conducted a factor analysis among 29 questionnaires which were related to a driver’s subjective workload. The results revealed that the 29 questionnaires could be divided to three factors (i.e. Situational Inadaptability, Interpersonal Inadaptability, Risk Taking Personality). In addition, Interpersonal Inadaptability and Risk Taking Personality factors also had significant effects on the DALI workload level. Of these factors, Situational Inadaptability factor had significant effects on NASA-TLX workload level. The purpose of this study was to determine a way of reducing a driver`s workload in advance and to provide people with an understanding of the theoretical driving workload. Given the results indicating specific factors affecting subjective workload, we expect that the results of this study will help drivers and researchers manage driving workload.

운전 시뮬레이션을 사용하여 차량 전방의 장애물 출현으로 인해 제어권 인수가 요구되는 3-수준 자율주행 상황에서 운전자의 주의분산 및 도로혼잡도 조건에 따른 제어권 인수시간(takeover time: TOT)과 장애물 회피에 대한 정신적, 신체적 작업부하에서의 차이를 비교하였다. 실험참가자들은 연령대에 따라 20대의 청년운전자 집단과 65세 이상의 고령운전자 집단으로 구분하였다. 주의분산은 자율주행 중 운전과 직접적으로 관련없는 과제(non-driving task: NDT)의 수행으로 유도되었고, 도로혼잡도 조건은 실험참가자 차량 주변의 차량 대수를 달리하여 조작하였다. 본 연구의 주요 결과와 시사점은 다음과 같다. 첫째, 자율주행 중의 NDT 미수행 조건에 비해 수행 조건에서, 그리고 한산도로보다는 혼잡도로에서 실험참가자들의 TOT가 유의하게 지체되었고, 제어권 인수 이후 장애물 회피 과정에서 경험하는 정신적, 신체적 작업부하의 수준도 유의하게 더 높았다. 둘째, 특히 이러한 경향은 청년운전자 집단에 비해 고령운전자 집단에서 더 뚜렷하였다. 이러한 결과는 혼잡한 도로에서 주의가 시각적, 청각적으로 분산될 경우 고령운전자 집단은 차량 전방의 장애물에 대한 안전하고 효과적인 회피 수행에서 어려움이 더 증가할 수 있다는 것을 시사한다.

This driving simulation study compared differences in driver’s takeover time (TOT) and subjective workload for obstacle avoidance under different conditions of road complexity and attention distraction in in a level-3 automated driving. Participants were divided into two groups: young drivers in their 20s and older drivers aged 65 or older. Attention distraction was induced by performing a non-driving task (NDT) during autonomous driving, and road complexity was manipulated by varying the number of vehicles surrounding the drivers’ vehicle. The main findings and implications of this study are as follows. First, drivers’ TOT was significantly delayed in the NDT condition compared to the non-NDT condition during automated driving, and in the congested traffic condition compared to the clear road condition. Furthermore, the level of mental and physical workload during obstacle avoidance through manual driving after control takeover was significantly higher. Second, this tendency was particularly pronounced in the older driver group compared to the younger driver group. The results of this study suggested that older drivers may experience increased difficulties in safe and effective avoidance regarding obstacles ahead of their vehicle when visually and audibly distracted on congested roads.

In driving situation, driver’s performance can be divided into primary task and secondary task. Many studies of primary task have been in progress, but those of secondary task are not implemented sufficiently. However, the driver’s error is greatly influenced by secondary task. In this study, an experiment was assessed to determine the relationship between the driver's operation time for the secondary task and mental workload due to speed changes in a driving simulation. The time to perform the secondary task was analyzed with Fitts’ Law, and mental workload was analyzed with RNASA-TLX(Revision of NASA-Task Load Index). The results has showed that the higher speed, the weaker the explanation by the use of Fitts' Law and the result of analyzing mental workload using RNASA-TLX was similar to the result of Fitts’ Law.

The aim of this research was to compare driver's workload among AHS (Automate Highway Systems) road sections in a virtual AHS environment that is based on a re Korean expressway in order to predict and compare the workloads imposed by the change (driver-vehicle interface and vehicle control authority. Road sections included the M (Manual Lane), TL1 (Transition Lane to enter the automated lane), AL (Automated Lane TL2 (Transition Lane to enter the manual lane after the end of automated driving), an post-AHS manual lane.

근래 폭발적인 휴대폰 사용자의 증가와 비례한 운전 중 휴대폰 사용에 의한 교통사고 빈도 및 상해정도의 증가는 운전 중 휴대폰 사용을 새로운 주요한 교통사고의 요인으로 떠오르게 하고 있다. 이는 휴대폰 사용에 의한 운전자의 조정 및 감시, 경계 행위의 방해, 인지 및 정신적 부하의 증가에 의한 '부적합한 경계 (improper lookout)'와 '부주의 (inattention)' 상태 발생에서 유발되며, 현재 많은 국가들이 법제정을 통한 운전 중 휴대 폰 사용금지를 실행중이거나 고려하고 있는 실정이다. 이에 본 연구는 현재 대부분의 국가에서 실질적 규제 대상에서 제외되어 있는 운전 중 핸드프리 휴대폰의 사용이 운전자의 부하 및 수행도에 미치는 영향을 시각분석 정신적 부하, 부가작업 수행도, 스티어링 엔트로피의 측정을 통하여 실시하였다. 실험은 일본 도시 중심부에서 실시되었으며, 결과는 부가작업의 형태에 따른 4가지의 실험상황과 시험구간의 직선부와 곡선부 (우회전) 사이의 비교분석 통하여 제시하였다. 또한, 실험설계, 적용평가방법, 및 실시과정에서의 문제점을 바탕으로 핸드폰관련 실제 도로시험을 위한 가이드라인을 제시한다.

Cellular Phone use while driving is one of the critical causes of traffic accident by falling the driver into the improper lookout and inattention situations by disturbing the driving behaviors and by increasing the driver's mental workloads. These days, therefore, governments in many countries are trying to Prohibit the cellular Phone use while driving by the law focused on the hand-held type of cellular phone. This Paper investigated the impacts on the hands-free cellular Phone use while driving to the drivers Performance among normal and two different level of secondary task driving conditions in the urban of Japan. As the results, quantitative differences of drivers eye movement, subjective mental workload, steering wheel angle entropy, and cognitive Performance of secondary tasks were compared between straight and curve (right turn) section for each driving condition.

The directions of the road are divided into two, the right-hand side and left-hand side of the road, by the convention and specific native method in the world. This paper deals with the characteristics and behaviors of drivers who are accustomed to driving on right-hand side of the road, drive with a handle on the left-hand side, and comparing with left-hand side drivers. The driver's eye movements were measured by eye camera and questionnaires were used for measuring subjective evaluation such as driving mental workload. The experimental results indicated even if the experts who had much experience on right-hand side driving, they had lower driving skill than novice driver, accustomed to driving on left-hand side. In terms of mental workload, MCH rating scale and MNASA-TLX, the right-hand side drivers were in lower stress condition than the left-hand side drivers because of having much driving experience. However, they conducted a few mistakes by confusing the position of turn signal and windshield wiper because of their driving habit or traits and it lead to operation mistakes. These results can be applied effectively to develop the driving support information with changed environments.

Driving is a complex psychomotor task often interrupted by secondary activities that increase cognitive workload and divert attention away from the roadway. The risk of inattentive driving is known to vary with age. To assess the impact of advancing age on driving performance under dual task condition, we evaluate the performance of 63 drivers divided into two age groups, younger (20-29) and older (60-69). This study considers driving behavior in the context of highway driving. Driving performance is composed the forward velocity, speed control and lateral control. Results indicate that age impacts both driving performance and compensatory behavior during dual load conditions.

졸음 운전 등 운전자의 상태 변화에 따른 자동차 사고가 급증하고 있으며 이를 방지하기 위한 시스템 구축 및 운전자의 상태를 판단하는 알고리즘 개발이 요구되어 지고 있다. 본 논문에서는 모의 주행 시스템을 통한 운전자의 심박변이도, 산호 포화도 (SPO2), 체온을 측정하여 운전자의 상태를 알려 주는 실험을 수행하였다. 즉, 심박변이도 (Heart rate variability, HRV) 분석을 위해 운전자의 심전도(Electrocardiogram, ECG) 신호를 획득 한 후 심전도 P,QRS, T 파형 중 R peak 을 자동으로 검출하였고 이를 통해 구한 R-R interval을 이용하여 HRV의 주요 파라메타를 시간영역(time domain)으로 해석하여 작업 환경에 따른 운전자의 상태를 비교 분석하였다.

The accidents caused by drivers while driving are considered as the major causes along with other causes such as conditions of roads, weather and cars. In this study, we investigated the driver's workloads under three different driving conditions (Weather, Driving time zone, and Traffic density) through analyzing biological signals obtained from a car driving simulator system. The proposed method is able to detect R waves and R-R interval calculation in the ECG. Heart rate variability (HRV) was investigated for the time domain to determine the changes in driver's conditions.

본 연구에서는 운전 시뮬레이션을 사용하여 자율주행 환경을 구현한 후 3-수준 자율주행 조건에서 자율주행 차량 (automated vehicle: AV)으로부터 운전자에게 전달되는 제어권 인수 요구(takeover request: TOR) 정보의 양상(시각, 청각 및 시각+청각) 및 도로 형태(직선도로와 곡선도로)에 따라 운전자의 제어권 인수 시간(takeover time: TOT) 및 정신적 작업부하(제어권 인수 이후에 운전자들이 경험한 주관적 작업부하와 심장박동수에서의 변화)가 어떻게 차별화되는지 분석하였다. 본 연구의 결과를 요약하면 다음과 같다. 먼저, AV로부터 TOR이 제시된 이후 실험참가자들이 보인 TOT에 대한 분석 결과, TOR 정보양상의 측면에서는 시각 정보가 가장 빠른 TOT를 이끌어 낸 반면 청각정보 조건에서 가장 느렸고, 도로 형태 측면에서는 직선도로 조건에 비해 곡선도로 조건에서의 TOT가 유의하게 더 느렸으며, 특히 청각 정보 조건에서 도로 형태에 따른 TOT에서의 차이가 가장 컸다. 둘째, 정신적 작업부하에 대한 분석 결과, TOR 정보가 시각 혹은 시각+청각적으로 제시된 조건에 비해 청각적으로 제시된 조건에서 주관적 작업부하 측정치와 심장박동수 변화 크기 모두 전반적으로 더 낮았고 특히, 심장박동수 변화의 경우 이러한 경향은 곡선도로 조건에서만 관찰되었다. 이러한 결과는 TOR 정보의 양상과 도로 형태에 따라 운전자의 TOT와 정신적 작업부하 수준이 달라질 수 있고, 특히 TOT가 빠를수록 정신적 작업부하 수준은 상대적으로 더 높아질 수 있음을 시사한다.

This study employed driving simulation to examine how takeover request (TOR) information modalities (visual, auditory, and visual + auditory) in Level-3 automated vehicles, and road types (straight and curved) influence the driver's control takeover time (TOT) and mental workload, assessed through subjective workload and heart rate variations. The findings reveal several key points. First, visual TOR resulted in the quickest TOT, while auditory TOR led to the longest. Second, TOT was considerably slower on curved roads compared to straight roads, with the greatest difference observed under the auditory TOR condition. Third, the auditory TOR condition generally induced lower subjective workload and heart rate variability than the visual or visual + auditory conditions. Finally, significant heart rate changes were predominantly observed in curved road conditions. These outcomes indicate that TOT and mental workload levels in drivers are influenced by both the TOR modality and road geometry. Notably, a faster TOT is associated with increased mental workload.

In developing the HMI(Human-Machine Interface) evaluation system for the IVNS(In-Vehicle Navigation System), design guidelines and evaluation methods are the most crucial problems for its use and efficiency. As the part of this system, focused on the final product of the database, subjective mental workload assessment is seriously considered to evaluate the driver's own driving task using the IVNS. This paper suggests the methodology for the ergonomic assessment of the IVNS that corresponds to the subjective measurement of the driver's mental workload by rating his or her own driving task. For this approach, Revision of NASA-Task Load Index(RNASA-TLX) was developed which translated and revised the version of NASA-TLX that is generally accepted an efficient and powerful method for evaluating the in-vehicle information systems. To verify the RNASA-TLX, an experiment was conducted in a real road situation, because the result of the laboratory approach is uncertain and has the differences from the real road test.