I’m curious,I’m open to it,I test it,I trust it! A focus groups study to understand a-priori trust in automated buses

Trust is regarded as one of the main predictors for adopting automated buses (ABs). However, theories about trust (development) in technology generally vary and an in-depths study about trust in ABs specifically is still outstanding. The present study fills this gap by presenting results from focus group interviews to trust (development) in shared automated buses prior to exposure. The objectives of this study are to contrast participants’ naïve concepts of trust with theory and to identify underlying factors influencing a-priori trust in ABs. Results show that the N = 21 focus group participants use different strategies to familiarise themselves with the new technology of ABs, e.g., comparisons with familiar technologies, fundamental tendencies to approach or avoid, additional information seeking, or anthropomorphisation. These strategies largely support existing theories on trust (development) in technology. Differences between naïve interpretations of trust and its theoretical assumptions were found in focus group debates where more control over technology limited uncertainty and led to more trust. While theories suggest control and trust to be incompatible opposites, participants see control as a way to enhance trust. We provide starting points for further theory development and expansion and stress the importance of explanations in emerging technologies for trust and acceptance building.     

Understanding the influence of in-vehicle information systems on range stress – Insights from an electric vehicle field experiment

Battery electric vehicle (BEV) drivers frequently report concerns of becoming stranded as a result of battery depletion, widely referred to as range stress, which constitutes a main obstacle to the adoption of these vehicles. One promising solution identified to mitigate range stress is to provide appropriate and accurate information through in-vehicle information systems (IVISs). Therefore, we aim to gain a broader understanding on the influence of specific IVISs on drivers’ range stress perception. To accomplish this, we performed a BEV field experiment in real traffic situations. By placing participants in a critical range situation, we could measure their psychometric range appraisal and psychophysiological feedback. The results of the psychometric evaluation revealed that individuals perceived the critical range situation as less challenging and threatening with the provided IVISs. Physiological indicators were found to be useful in complementing questionnaire-based evaluation methods within the field of range stress. Although the findings of the psychophysiological measurement revealed that IVISs-equipped participants exhibited increases in stress perception over time due to volatile range feedback, the average stress level was observed to be lower throughout the entire driving task.     

Drinking patterns and drunk-driving behaviour in Catalonia,Spain: A comparative study

This study explores three alcohol-related databases so as to provide a comprehensive understanding of drinking patterns and the prevalence of alcohol-impaired driving in Catalonia (Spain). The rate of alcohol-impaired drivers is compared with the percentage of drinkers in this population, with a particular focus on heavy episodic drinkers. Two strategies adopted by law enforcement agents when conducting alcohol breath tests are examined: (i) non-random and (ii) random approaches to roadblock location and driver selection. We find that heavy drinker profiles (in terms of age and gender) closely match those of alcohol-impaired drivers detected at strategically located, non-random sobriety checkpoints (especially in the case of female drivers), and that they also correlate with the age-gender distribution of drivers involved in road accidents with victims. Different drink driving patterns are detected when sobriety checkpoints are located randomly and drivers are tested at random. Older drivers are identified as a risk group as they abandon the safer driving habits in relation to alcohol shown when they were middle-aged. A combination of non-random and random controls would increase driver perception of their chances of being detected when drink driving. As such, the whole population, regardless of their drinking profile, would be alerted to the serious personal, social and legal implications of alcohol-impaired driving.     

Effects of Self‐Affirmation,Narratives, and Informational Messages in Reducing Unrealistic Optimism About Alcohol‐Related Problems Among College Students

This study examines intervention approaches to improve the accuracy of risk judgments among college students with unrealistic optimism about alcohol‐related problems. We conducted a randomized experiment with 2 self‐affirmation (affirmed, nonaffirmed) and 3 message conditions (narrative, informational, no treatment control). Results indicate that providing risk information to unrealistic optimists, while concomitantly protecting their self‐concept via either self‐affirmation or narratives, may reduce defensive reactions and align their perceived risk more closely with their actual risk. Self‐affirmation reduced unrealistic optimism only among those exposed to an informational message, not those exposed to a narrative. The narrative message appeared to increase perceived risk among unrealistic optimists via transportation and identification with the character. We discuss theoretical and practical implications of this work.     

On-Road vehicle study of the experience of automated driving

Prior studies of automated driving have focused on drivers’ evaluations of advanced driving assistance systems and their knowledge of the technology. An on-road experiment with novice drivers who had never used automated systems was conducted to examine the effects of the automation on the driving experience. Participants drove a Tesla Model 3 sedan with level 2 automation engaged or not engaged on a 4-lane interstate freeway. They reported that driving was more enjoyable and less stressful during automated driving than manual driving. They also indicated that they were less anxious and nervous, and able to relax more with the automation. Their intentions to use and purchase automated systems in the future were correlated with the favorableness of their automated driving experiences. The positive experiences of the first-time users suggest that consumers may not need a great deal of persuading to develop an appreciation for partially automated vehicles.     

Humanizing autonomous vehicle driving: Understanding,modeling and impact assessment

The advent of autonomous vehicles brings major changes in the transportation systems influencing the infrastructure design, the network performance, as well as driving functions and habits. The penetration rate of this new technology highly depends on the acceptance of the automated driving services and functions, as well as on their impacts on various traffic, user oriented and environmental aspects. This research aims to present a methodological framework aiming to facilitate the modelling of the behaviour of new AV driving systems and their impacts on traffic, safety and environment. This framework introduces a stepwise approach, which will be leveraged by stakeholders in order to evaluate the new technology and its components at the design or implementation phase in order to increase acceptance and favor the adoption of the new technology. The proposed framework consists of four sequential steps: i. conceptual design, ii. data collection, processing and mining, iii. modelling and iv. autonomous vehicles impact assessment. The connection between these steps is illustrated and various Key Performance Indicators are specified for each impact area. The paper ends with highlighting some conceptual and modeling challenges that may critically affect the study of acceptance of autonomous vehicles in future mobility scenarios.     

The effects of adaptive cruise control (ACC) headway time on young-experienced drivers' overtaking tendency in a driving simulator

The preference to maintain a certain desired speed is perhaps the most prevalent explanation for why a driver of a manually driven car decides to overtake a lead vehicle. Still, the motivation for overtaking is also affected by other factors such as aggressiveness, competitiveness, or sensation-seeking caused by following another vehicle. Whether such motivational factors for overtaking play a role in partially automated driving is yet to be determined. This study had three goals: (i) to investigate whether and how a driver's tendency to overtake a lead vehicle changes when driving a vehicle equipped with an adaptive cruise control (ACC) system. (ii) To study how such tendencies change when the headway time configuration of the ACC system varies. (iii) To examine how the manipulation of the speed and speed variance of the lead vehicle affect drivers' tendencies to overtake a lead vehicle. We conducted two different experiments, where the second experiment followed the first experiment's results. In each experiment, participants drove three 10–12 min simulated drives under light traffic conditions in a driving simulator under manual and level one (L1) automation driving conditions. The automation condition included an ACC with two headway time configurations. In the first experiment, it was 1 sec and 3 secs, and in the second, it was 1 sec and 2 secs. Each drive included six passing opportunities representing three different speeds of the lead vehicle (−3 km/h, +3 km/h, +6 km/h relative to the participant), with or without speed variance. Results show that drivers tended to overtake a lead vehicle more often in manual mode than in automated driving modes. In the first experiment, ACC with a headway time of 1 sec led to more overtaking events than ACC with 3 secs headway time. In addition, the relative speed of the lead vehicle and its speed variability affected overtaking tendencies. In the second experiment, the relative speed of the lead vehicle and its speed variability affected overtaking tendencies only when interacting with each other and with driving configuration. When the speed of the lead vehicle was +3 km/h and included variability, more overtaking events occurred in manual mode than both automation modes. This work has shown that driving with ACC might help reduce overtaking frequencies and more considerable when the headway time is set to 3 secs.     

What Would It Take to Get You into an Electric Car? Consumer Perceptions and Decision Making about Electric Vehicles

Americans buy millions of vehicles every year, but research on how those decisions are made, including personality and individual difference factors, has rarely taken full advantage of psychological insights. This is an increasingly important topic because, for instance, decisions to buy electric vehicles (EVs) rather than gasoline-powered vehicles have environmental and geopolitical consequences. A series of studies reveal the very different perceptions of EVs and gas vehicles. Although vehicle choices at the aggregate level were strongly correlated with economic considerations, individual consumer choices were correlated with delay discounting rates in Study 1 but not Study 2. These studies also did not find significant correlations between EV purchase decisions and a number of other individual difference traits often thought to be factors in such decisions (i.e., social value orientation, political attitudes, environmental attitudes, preference for novel products, or an array of core social values). Regression models indicate that factors which did predict vehicle choices concerns were about the performance and range of EVs, EV prevalence in general, and beliefs about what statements different vehicle types made about their owners and the owners’ values. More attention to the vehicle-associated values and immediate performance/use issues can help to promote EV purchase decisions and subsequent improvements in environmental and political stability.     

自动驾驶汽车与行人交互中的沟通界面设计：基于行人过街决策模型的评估

自动驾驶汽车要进入人车混行的普通道路, 需确保与过街行人之间的交互安全和效率。为解决这一问题, 高等级自动驾驶汽车往往在车辆外部装置显示设备, 即外部人机界面(eHMIs)以和行人沟通信息。在具体设计上, 已有研究主要采用文字、图形、投影等视觉沟通形式, 传达车辆状态(是否在自动驾驶模式)、意图和对行人的过街建议等沟通信息, 并在真实路段实验、虚拟场景及实验室实验等情境中评估了界面的使用对行人过街意向、速度和准确性等指标的影响。然而, 以行人为中心的外部界面设计需系统地支持行人过街决策前各阶段的信息加工需求。因此, 我们结合行人过街决策过程和情境意识理论, 提出行人与自动驾驶汽车交互中的动态过街决策模型, 从行人认知加工视角评估各种界面的沟通效果。评估的结果启示, eHMIs应促进行人对车辆信息的感知、理解和预测。在感知阶段, 应采用多种类型界面、多呈现载体相结合, 增强信息的可识别性。在理解阶段, 需结合文字说明、合理选择沟通视角、信号标准化和培训提高可理解性。在预测阶段, 应结合车辆内隐运动信息, 帮助行人快速准确获取车辆未来行动意图。更重要的是, 未来研究应关注在多行人、多车辆混行情境下的信息沟通设计及其对行人的影响。理论方面, 未来研究也需要关注外部界面如何通过自下而上的通路影响情境意识和心智模型的形成。     

The impact of a dedicated lane for connected and automated vehicles on the behaviour of drivers of manual vehicles

Connected and automated vehicles (CAVs) are expected to enhance traffic efficiency by driving at shorter time headways, and traffic safety by shorter reaction times. However, one of the main concerns regarding their deployment is the mixed traffic situation, in which CAVs and manually driven vehicles (MVs) share the same road.This study investigates the behavioural adaptation of MV drivers in car-following and lane changing behaviour when they drive next to a dedicated lane (DL) for CAVs and compares that to a mixed traffic situation. The expectation is that in a mixed traffic situation, the behavioural adaptation of MV drivers is negligible due to lower exposure time and scarce platoons, while concentrating the CAVs on one dedicated lane may cause significant behavioural adaptation of MV drivers due to a higher exposure time and conspicuity of CAV platoons.Fifty-one participants were asked to drive an MV on a 3-lane motorway in three different traffic scenarios, in a fixed-base driving simulator: (1) Base, only MVs were present in traffic, (2) Mixed, platoons of 2–3 CAVs driving on any lane and mixed with MVs, (3) DL, platoons of 2–3 CAVs driving only on a DL. The DL was recognizable by road signs and a buffer demarcation which separated the DL from the other lanes. A moderate penetration rate of 43% was assumed for CAVs.During the drives, the car following headways and the accepted merging gaps by participants were collected and used for comparisons of driving behaviour in different scenarios.Based on the results, we conclude that there is no significant difference in the driving behaviour between Base and Mixed scenarios at tested penetration rate, confirming our research expectation. However, in DL scenario, MV drivers drove closer to their leaders specially when driving on the middle lane next to the platoons and accepted shorter gaps (up to 12.7% shorter at on-ramps) in lane changing manoeuvres. Dedicating a lane to CAVs increases the density of CAV platoons on one lane and consequently their conspicuity becomes higher. As a result, MV drivers are influenced by CAV platoons on a DL and imitate their behaviour.The literature suggests that dedicating a lane to CAVs improves the traffic efficiency by providing more possibilities for platooning. This study shows that implementing such a solution will affect the driving behaviour of human drivers. This should be taken into consideration when evaluating the impacts of dedicated lanes on traffic efficiency and traffic safety.