Analysing the influence of attitude and habit on bicycle commuting

New transport trends have emerged in developing countries to promote bicycling due to its individual and societal benefits. Although bicycle infrastructure provision has been one of the most utilised strategies to encourage bicycling, it has had a limited immediate impact on the bicycling modal share. Published research indicates the need to incorporate the psychosocial dimension to understand commuters' transport behaviour and explain why bicycling infrastructure usage is lower than expected. This study highlights the processes behind bicycle mode choice decisions, explicitly incorporating pro-bicycle attitudes and habits, while also considering the influence of socioeconomic, bicycle facilities and bicycling experience variables on shaping that attitude. For this purpose, an online survey was designed and sent to students, faculty members and staff of two Chilean universities to collect ad-hoc data. The modelling used an approach based on an integrated choice and latent variable model. The main findings are: attitude in itself is a relevant construct to explain behaviour; bicycling infrastructure contribute to explain bicycle choice but only indirectly through attitude; socioeconomic characteristics, bicycling familiarity and practical issues have both a direct effect on bicycle choice decision and an indirect one by fostering pro-bicycling attitudes. Additionally, results show that the explicit inclusion of habit reduces the contribution of pro-bicycle attitude in explaining bicycle choice. This might be due to interaction and reinforcement between habit and attitude.     

“Going through a little bit of growing pains”: A qualitative study of the factors that influence the route choice of regular bicyclists in a developing cycling city

As cities make concerted efforts to become more bicycle-friendly through policy changes and infrastructure, it is important that such efforts ultimately support people who currently bicycle and remove barriers that may prevent more people from bicycling. Travel surveys can reveal the nature and distribution of bicycling trips, but perceptions and behaviours of bicyclists are better understood through qualitative methods. In particular, developing cycling cities are unique settings to examine how the built environment supports bicycling as changes are made to increase bicycling levels. Through semi-structured interviews, this research explores the case of Hamilton, Ontario and the factors that influence route choice from the perspective of regular bicyclists. Major themes were identified using thematic analysis: (i) exclusion from road space; (ii) infrastructure; and (iii) streetscape. Bicyclists highly value infrastructure and seek routes that minimize interactions with cars, while avoiding many arterial roads that prioritize motorists. Routes that appear to be more human-oriented or that have nature are also attractive. Many regular bicyclists report that current bicycle infrastructure does not meet their preferences. Despite building nearly half of the planned infrastructure network, our findings suggest the built environment is not perceived to be oriented to bicycling. This study provides policy and practice recommendations for developing cycling cities in North America as they transition towards established cycling cities.     

Can a twelve-week intervention reduce barriers to bicycling among overweight adults in low-income Latino and Black communities?

This pilot study summarizes perceived barriers to bicycling among overweight adults in two low-income communities of color and evaluates the impact of a bicycling intervention on these perceived barriers. A randomized controlled trial with 38 total participants from one predominantly Latino and one predominantly Black neighborhood in Milwaukee, Wisconsin was conducted during summer 2015. The twelve-week intervention consisted of group bicycle rides and bicycling instruction. Several barriers identified prior to the intervention declined significantly among intervention group members soon after it was completed: not feeling healthy enough to bike, being physically uncomfortable while biking, not having a bicycle to use, not having other people to bicycle with, not knowing the best routes to use, not feeling safe from crime, not feeling safe from car traffic, and worrying that neighbors do not think it is normal for an adult to ride a bike. Eight weeks after completion, the intervention group reported significantly greater reductions than the control group with respect to the barriers of not feeling healthy enough to bike and not feeling safe from car traffic. In addition to decreasing barriers, qualitative analysis suggested that increasing support from family and friends as well as emphasizing personal health benefits could help motivate people to bicycle.     

Crashes and other safety-related incidents in the formation of attitudes toward bicycling

Many cities are encouraging bicycling as mode of transportation as a way to improve air quality and health. Evidence suggests a strong influence of attitudes on bicycling, but few studies have examined the formation of attitudes toward bicycling. This paper explores the potential effect of crashes and other incidents on attitudes towards bicycling. Several themes emerge from 54 in-depth interviews on experiences with bicycling over the life course for a sample of adults living in Davis, California. The greater the severity of injuries associated with a crash, the greater the likelihood of declines in comfort with and desire for bicycling. Crashes in youth had very little effect on desire for or comfort with bicycling, but the opposite was true of crashes in adulthood. Incidents involving motorists particularly exacerbated discomfort with bicycling, while solo crashes were commonly perceived as unlucky or careless mishaps. Crashes experienced by others, as opposed to those experienced personally, were especially damaging to attitude, particularly for those who did not bicycle regularly. These findings have important implications for the design of bicycle facilities and programs.     

Why male adolescent bicyclists perform risky stunts? A qualitative study

Stunts are one of the main reasons for traffic accidents, particularly among male adolescent bicyclists (ABs). Nonetheless, there are limited data about the theoretical framework of its contributing factors. Moreover, the theoretical frameworks explaining the factors contributing to other risky behaviors have not been used in the area of risky bicycle stunts. The aim of this qualitative study was to explore the factors contributing to risky stunts among male ABs in Iran. This qualitative study was conducted from September 2019 to December 2020 using conventional content analysis. Participants were 29 male ABs purposively selected from Isfahan, Iran. Data were collected through eighteen interviews with sixteen ABs and three focus group discussions with thirteen ABs. Data analysis was conducted concurrently with data collection through conventional qualitative content analysis. The mean of participants’ age was 16.4 ± 1.1 years. Factors contributing to their engagement in risky stunts were grouped into three main themes, namely predisposing personal factors (such as risk underestimation, perceived superiority, sensation seeking, emotional condition, and previous stunt-related experiences), reinforcing social factors (such as supportive social norms and weaknesses of traffic regulations), and environmental conditions (such as time conditions and structural factors). This study provides a new classification of the facilitators to risky stunts among male ABs and reveals new facilitators to these stunts, namely perceived superiority and police non-deterrent reactions to stunts. Therefore, programs on the improvement of safe bicycling should focus not only on perceptual and emotional factors and correction of false perceived superiority through education, but also on social norms and beliefs, regulations, and environmental factors.     

Why do people like bicycling? Modeling affect toward bicycling

Studies show that the way an individual feels about bicycling – the degree to which they like bicycling – is an important predictor of whether or not they bicycle. But why do some people like bicycling and others don’t? This study explores factors that may influence an individual’s liking of bicycling, or more formally, their bicycling affect. We analyze a rich dataset from a cross-sectional survey of residents of six small U.S. cities using an ordered logit model. Results show that bicycling behavior has the strongest association with liking bicycling, with bicycling constraints following as the second most important factor. Individual cognitions, including perceptions and normative beliefs, also play important roles in predicting bicycling affect. Individual measures of the physical environment do not correlate with liking of bicycling, but the perception that biking to various destinations is safe does. Social environment factors influence liking of bicycling as well. Longitudinal research is needed to better understand the reciprocal relationship between bicycling affect and bicycling behavior as well as the effect over time of factors such as the physical environment. Nevertheless, this study offers an initial understanding of the potential determinants of bicycling affect that provides a starting point for further research as well as direction for the development of policies for getting more people on bicycles.     

Modeling the impact of traffic conditions and bicycle facilities on cyclists’ on-road stress levels

Past research efforts have shown that cyclists’ safety, stress, and comfort levels greatly affect the routes chosen by cyclists and cycling frequency. Some researchers have tried to categorize cyclists’ levels of traffic stress utilizing data that can be directly measured in the field, such as the number of motorized travel lanes, motorized vehicle travel speeds, and type of bicycle infrastructure. This research effort presents a novel approach: real-world, on-road measurements of physiological stress as cyclists travel across different types of bicycle facilities at peak and off-peak traffic times. By matching videos with stressful events, it was possible to observe the circumstances of those stressful events. The stress data was normalized, and the method was carefully validated by a detailed analysis of the stress measurements. Novel statistical results from a multi-subject study quantifies the impact of traffic conditions, intersections, and bicycle facilities on average stress levels.     

The effects of operating a touch screen smartphone and other common activities performed while bicycling on cycling behaviour

Although it has been shown that making phone calls or sending text messages while riding a bicycle can have a negative impact on bicyclist’s behaviour, in countries such as the Netherlands the operation of a mobile phone while cycling on a bicycle is not illegal and is actually quite common. In recent years conventional mobile phones with a physical keypad are increasingly being replaced by smartphones with a touch screen. The operation of a touch screen phone ironically cannot be done purely ‘by touch’ due to the lack of tactile feedback, and instead requires fixations on a relatively small screen. The question therefore can be asked whether the operation of touch screen telephones deteriorates cycling behaviour more than operation of a conventional mobile phone.Twenty-four participants completed a track on their own bicycle while sending a text message from a conventional and a touch screen mobile phone. In addition the effects of other common activities that can accompany bicycling were studied, including texting at the same time as listening to music, talking on a mobile phone or cycling next to someone and speaking with this companion, and playing a game on a touch screen phone while bicycling. The impacts of all the above conditions on cycling performance and visual detection performance were compared with control conditions in which participants cycled with either one or two hands on the handlebars and were not required to perform any secondary tasks.Bicycle speed was reduced in all telephone conditions and in the condition when cycling next to someone. Lateral position variation increased in all telephone conditions. Use of the touch screen led to a more central position in the cycle lane and resulted in worse visual detection performance compared with the operation of a conventional mobile phone. The main effect of listening to music was that an auditory signal to stop cycling was missed by 83% of the participants. In conclusion, while all investigated types of phone deteriorated cycling performance, the use of a touch phone has a larger negative effect on cycling performance than a conventional mobile phone. With touch screen smartphones taking the place of conventional mobile phones and being used for other purposes than verbal communication, these effects on cycling performance pose a threat to traffic safety.     

Investigating relationships among perceptions of yielding,safety, and comfort for pedestrians in unsignalized crosswalks

Interactions with other road users influence the perceived safety and comfort of pedestrians. Yet the relationships among perceptions of yielding, safety, and comfort are poorly understood. To enhance understanding of these key concepts, the objectives of this study are to determine how perception of pedestrian safety at unsignalized crosswalks differs from perception of comfort, and the relationship of each with perception of yielding. A generalized structural equations model is developed using data from an online survey in which 366 participants (i.e., “perceivers”) rated yielding, safety, and comfort for sample videos of pedestrian interactions with motor vehicles and bicycles. Results show that an individual’s perception of yielding plays a crucial role in mediating the effects of interaction attributes (e.g., vehicle speed, proximity) and perceiver attributes (e.g., travel habits) on their perceptions of pedestrian safety and comfort. For example, people who bicycle more frequently perceive pedestrians as more comfortable than people who walk more frequently, rooted in misalignment on what constitutes adequate yielding. Strategies to address pedestrian comfort can focus on a set of key yielding behaviors by drivers and cyclists – particularly allowing the pedestrian to cross first. Motor vehicle drivers must exhibit stronger yielding behavior (e.g., allow a larger time gap) than bicycles to achieve the same level of perceived pedestrian safety and comfort. Although perceptions of safety and comfort are strongly related and similarly impacted by yielding, researchers should be cautious about using the concepts interchangeably because they are differently impacted by attributes of the interaction and perceiver.     

Who is the typical bicyclist?

Promoting bicycling is important for individual health, environmental sustainability and transport demand management. However, very few people use a bicycle on a regular basis. This paper explores what views bicyclists and non-bicyclists in England may hold about the typical bicyclist and how such views are related to bicycling behaviour and intentions. A survey was conducted among 244 bicyclists and non-bicyclists. On the basis of a range of statements on behaviour, motivation and characteristics of the typical bicyclist, four different stereotypes could be distinguished: responsible, lifestyle, commuter and hippy-go-lucky. These views differed between bicyclists and non-bicyclists. Moreover, independent of past bicycling behaviour, reported intentions to use a bicycle in the future were positively related to perceptions of the typical bicyclist as a commuter or hippy-go-lucky bicyclist. These findings have implications for encouraging bicycling, which may benefit from promoting bicycling as a common day-to-day activity rather than something that is only relevant for a few.     

Physiological responses to urban design during bicycling: A naturalistic investigation

The current research set out to measure the moderating effect that urban design may have on bicyclist physiology while in transition. Focusing on the hilly City of Wuppertal, Germany, we harnessed bicyclists with mobile sensors to measure their responses to urban design metrics obtained from space syntax, while also adjusting for known traffic, terrain, and contextual factors. The empirical strategy consisted of exploratory data analysis (EDA), ordinary least squares (OLS), and a local regression model to account for spatial autocorrelation. The latter model was robust (R² = 68%), and showed that two statistically significant (p < 0.05) urban design factors influenced bicyclist physiology. Controllability, a measure of how spatially dominated a space is, increased bicyclist responses (i.e., decreased comfortability); while integration, which is related to accessibility and connectivity, had the opposite effect. Other noteworthy covariates included one-way streets and density of parked automobiles: these exerted a negative influence on bicyclist physiology. The results of this research ultimately showed that nuanced urban designs have a moderate influence on bicycling comfort. These outcomes could be utilized by practitioners focused on implementing appropriate interventions to increase bicyclist comfort levels and this mode share.     

Unsafety on two wheels,or social prejudice? Proxying behavioral reports on bicycle and e-scooter riding safety – A mixed-methods study

The use of non-motorized transportation and micro-mobility is increasing in many cities. Bicycle riding and e-scooter use are now more common and affordable than ever. However, users of these devices face certain key issues. These include their own risky behaviors as well as involvement in conflicts with other road users. Self-report data may not adequately capture these behaviors and interactions. Despite this, more objective data (i.e., how third parties perceive these users’ road behaviors) is scarce. Aims: This study aimed to understand whether e-scooter riders have comparable or different riding behaviors than cyclists. This was investigated using a mixed-method study. Methods: This paper is divided into two sub-studies. In Study 1, 950 Spanish non-cyclists and non-e-scooter riders (mean age 31.98 ± 13.27 years; 55.3% female) provided external ratings (proxies) regarding the perceived behaviors of bicycle and e-scooter riders. In Study 2, collective Rapid Assessment Processes (RAPs; n = 23) were used to develop qualitative configurations of some of the key risky behaviors highlighted in Study 1. Results: There were significant differences in the perceived errors and violations rated by proxies for both types of riders (with e-scooter riders perceived as having higher rates of risky behaviors). However, there were also structural differences in the effects of external raters’ risk perceptions, traffic rule knowledge, and traffic incidents with two-wheeled riders on how they rated the behaviors. Conclusion: The results of both studies suggest that external raters’ perceptions provide further understanding of the causes, dynamics, and conflicts related to road behaviors performed by certain groups of road users. This is particularly apparent when there is no clear legislation and information on safe riding in urban areas. In this sense, improving infrastructure could promote safer interactions. Finally, road safety education could focus on promoting safer practices and interactions in order to improve how others perceive riders’ behavior.     

Cyclist efficiency and its dependence on infrastructure and usual speed

Bicyclists are a heterogeneous group, with varying abilities, traffic education and experience. While efficiency was identified as an important factor on utility bicycle trips, it might be traded for experienced safety, for example by choosing different pathways in a given situation, or by relinquishing one’s right of way. In a semi-controlled study with 41 participants, a grouping was made according to self-reported riding speed in relation to other cyclists. The participants cycled twice along a 3 km inner-city route, passing four intersections with different priority rules. The cyclists were free to choose how to negotiate the intersections. Speed and the traffic surroundings were recorded via gps and cameras on the bike of the participant and of a following experimenter. For each cyclist, the ‘base’ speed on undisturbed segments was determined as reference. Based on this, the efficiency in different types of intersections was computed per cyclist group. It turned out that infrastructural aspects, cyclist group and the presence and behaviour of interacting traffic influenced cyclist efficiency. Faster cyclists were delayed more when the infrastructure required a stop regardless of the traffic situation, like at a red traffic light or a stop sign. The members of the so-called ‘comfort cyclists’ group were delayed the most in a roundabout with mixed traffic, where many chose to get off their bike and walk. In a society working for equality of access to the transport system, it is recommended to develop solutions that consider and accommodate the behaviours of different cyclist groups when planning bicycling infrastructure.     

Perceived discrimination amongst young people in socio‐economically disadvantaged communities: Parental support and community identity buffer (some) negative impacts of stigma

There is increasing acceptance that children are not unaware of when they are targets of discrimination. However, discrimination as a consequence of socio‐economic disadvantage remains understudied. The aim of this study was to examine the impact of perceived discrimination on well‐being, perceptions of safety and school integration amongst children growing up within socio‐economically disadvantaged communities in Limerick, Ireland. Mediation analysis was used to explore these relationships and to examine the potential role of parental support and community identity in boys and girls in the 6th to 9th year of compulsory education (N = 199). Results indicate perceived discrimination contributed to negative outcomes in terms of school integration, perceptions of safety and levels of well‐being. Age and gender differences were observed which disadvantaged boys and younger children. All negative outcomes were buffered by parental support. Community identity also protected young people in terms of feelings of school integration and risk but not in terms of psychological well‐being. Findings are discussed in terms of the different role of family and community supports for children negotiating negative social representations of their community.     

Sharing the road with autonomous vehicles: A qualitative analysis of the perceptions of pedestrians and bicyclists

Public perception assessment is important for gaining a better understanding of the acceptance of autonomous vehicles (AVs) and identifying potential ways to resolve public concerns. This study investigated how pedestrians and bicyclists perceived AVs based on their knowledge and road sharing experiences, applying a combined inductive and deductive data analysis approach. Survey responses of pedestrians and bicyclists in Pittsburgh, Pennsylvania, USA collected by Bike Pittsburgh (BikePGH) in 2019, were analyzed in this research. AVs following traffic rules appropriately and AVs driving safer than the human drivers were the most notable positive perceptions towards AVs. Pedestrians and bicyclists showed comparatively fewer negative perceptions towards AVs than positive perceptions. Negative perceptions mostly included a lack of perceived safety and comfort around AVs and trust in the AV technology. Respondents also concerned about AV technology issues (e.g., slow and defensive driving, disruptive maneuver), while sharing the road with AVs. Perceptions of the respondents were significantly influenced by their views on AV safety, familiarity with the technology, the extent respondents followed AV on the news, and household automobile ownership. Regulating AV movement on roadways, developing safety assessment guidelines, and controlling oversights of improper practices by AV companies were the major suggestions from the survey participants. Findings of this study might help AV companies to identify potential improvement needed in AV technology to increase pedestrians and bicyclists acceptance, and policymakers to develop policy guidelines to ensure safe road sharing among pedestrians, bicyclists, and AVs.     

Are they really interested but concerned? A mixed methods exploration of the Geller bicyclist typology

The Geller typology, which categorizes the population into four types of bicyclists (strong and fearless, enthused and confident, interested but concerned, and no way no how) has gained considerable popularity amongst researchers and planners. One large U.S. study used a survey-derived approach to categorize respondents into Geller’s typology, and found the majority of Americans were “interested but concerned”. While the U.S. findings are widely cited in planning documents, there has yet to be an assessment as to whether this indirect survey-derived categorization into Geller’s typology corresponds with how bicyclists perceive themselves. Using a mixed methods approach, we explored the Geller typology from the view of bicyclists themselves. Our specific objectives were to assess whether the survey-derived categorization method aligned with bicyclists’ perceptions, and to also examine bicyclists’ interpretations of Geller’s typology. We conducted a cross-sectional survey of bicyclists (n = 281) and interviews with a subset of participants (n = 25). According to the survey-derived categorization, the distribution of the sample (n = 25) was: 4% strong and fearless, 12% enthused and confident, and 84% interested but concerned. In the interviews we learned there was only a match between survey-derived and self-perceived bicyclist type for seven of twenty-five (28%) participants. When asked, participants were more likely to categorize themselves to strong and fearless (24% overall) or enthused and confident (52% overall). Our findings suggest that the category titles are intuitive, however, the survey-derived categorization does not necessarily match with how bicyclists perceive themselves. This suggests that, at least for those who currently bicycle, a direct approach of asking people which type of bicyclist they identify with may be preferable.     

Evaluating bicyclists’ risk perception using video clips: Comparison of frequent and infrequent city cyclists

Hazard and risk perception has been studied extensively among car drivers, and their link to crash involvement is established. Bicyclists, in particular, are vulnerable road users. Better understanding of their risk and hazard perception could help to improve their traffic safety.In this study, we investigated the risk perception of bicyclists in a city environment. Two groups of bicyclists were compared: 19 frequent and 19 infrequent bicyclists. Participants were shown video clips taken with a camera attached to the handlebar of a bicycle, and they were asked to continuously indicate with a slider how much caution the situation needed.The frequent cyclists had more frequent rises in the caution estimate, which suggest that they anticipated or detected more hazards than infrequent cyclists. This is in line with the classical hazard perception results, which link the car driving experience to faster and more accurate hazard perception. The overall level or caution was not directly related to the rise event rate or bicycling frequency. Those cyclists who reported typically cycling faster than others showed elevated overall level of caution on sidewalks compared with others, but there was no difference on bike paths.     

Cyclists' perception of cycling infrastructure – A Repertory Grid approach

Previous research indicate that cyclists prefer safe and comfortable infrastructure. However, concepts like safety or comfort may be understood and defined in different ways by different individuals. Moreover, these concepts are so broad that it is unclear to which specific characteristics of the traffic infrastructure they are linked. Therefore, the aim of this study is to inductively examine individual evaluation criteria that cyclists use to perceive and evaluate certain route attributes. Using the Repertory Grid technique, we elicited the personal constructs of 23 participants about given route attributes and asked them to rate every attribute on every construct. The constructs were categorized and clustered resulting in five evaluation criteria, namely Mental Comfort, Physical Comfort, Interaction, Environment, and Ease of Use. Both comfort clusters were rated the most relevant for route choice, but they strengthen the suggestion of two distinct aspects of comfort, one referring to mental stress, the other referring to physical effort. Furthermore, the analyses revealed Interaction as a relatively new route criterion which also raises a new view on the negative evaluation of motor traffic and expands the concept of stress. Regarding the evaluation of route attributes, a high traffic volume and cobbled stone were rated the most negative, whereas separated cycling facilities were evaluated as most positive. Findings of this study expand existing research by qualitative insights and provide a more detailed understanding of route criteria like comfort or safety. This can be used to enhance cycling facilities and to offer preferable infrastructure for cyclists.     

Using naturalistic data to assess e-cyclist behavior

In Europe, the use of electric bicycles is rapidly increasing. This trend raises important safety concerns: Is their use compatible with existing infrastructure and regulations? Do they present novel safety issues? How do they impact other traffic? This study sought to address these concerns, using instrumented electric bicycles to monitor e-cyclists’ behavior in a naturalistic fashion. Data was collected from 12 bicyclists, each of whom rode an instrumented bicycle for two weeks. In total, 1500 km worth of data were collected, including 88 critical events (crashes and near-crashes). Analysis of these critical events identified pedestrians, light vehicles and other bicycles as main threats to a safe ride. Other factors also contributed to crash causation, such as being in proximity to a crossing or encountering a vehicle parked in the bicycle lane. A comparison between electric and traditional bicycles was enabled by the availability of data from a previous study a year earlier, which collected naturalistic cycling data from traditional bicycles using the same instrumentation as in this study. Electric bicycles were found to be ridden faster, on average, than traditional bicycles, in addition to interacting differently with other road users. The results presented in this study also suggest that countermeasures to bicycle crashes should be different for electric and traditional bicycles. Finally, increasing electric bicycle conspicuity appears to be the easiest, most obvious way to increase their safety.     

Manual drivers’ experience and driving behavior in repeated interactions with automated Level 3 vehicles in mixed traffic on the highway

In the near future, conditionally automated vehicles (CAVs; SAE Level 3) will travel alongside manual drivers (≤ SAE level 2) in mixed traffic on the highway. It is yet unclear how manual drivers will react to these vehicles beyond first contact when they interact repeatedly with multiple CAVs on longer highway sections or even during entire highway trips. In a driving simulator study, we investigated the subjective experience and behavioral reactions of N = 51 manual drivers aged 22 to 74 years (M = 41.5 years, SD = 18.1, 22 female) to driving in mixed traffic in repeated interactions with first-generation Level 3 vehicles on four highway sections (each 35 km long), each of which included three typical speed limits (80 km/h, 100 km/h, 130 km/h) on German highways. Moreover, the highway sections differed regarding the penetration rate of CAVs in mixed traffic (within-subjects factor; 0%, 25%, 50%, 75%). The drivers were assigned to one of three experimental groups, in which the CAVs differed regarding their external marking, (1) status eHMI, (2) no eHMI, and (3) a control group without information about the mixed traffic. After each highway section, drivers rated perceived safety, comfort, and perceived efficiency. Drivers were also asked to estimate the penetration rate of CAVs on the previous highway section. In addition, we analyzed drivers’ average speed and their minimum time headways to lead vehicles for each speed zone (80 km/h, 100 km/h, 130 km/h) as well as the percentage of safety critical interactions with lead vehicles (< 1 s time headway). Results showed that manual drivers experienced driving in mixed traffic, on average, as more uncomfortable, less safe and less efficient than driving in manual traffic, but not as dangerous. A status eHMI helps manual drivers identify CAVs in mixed traffic, but the eHMI had no effect on manual drivers’ subjective ratings or driving behavior. Starting at a level of 25% Level 3 vehicles in mixed traffic, participants' average speed decreased significantly. At the same time, the percentage of safety critical interactions with lead vehicles increased with an increasing penetration rate of CAVs. Accordingly, additional measures may be necessary in order to at least keep the existing safety level of driving on the highway.