Re-inventing the journey experience: ‘life on board’ the autonomous vehicle of the future

The automotive industry is facing a paradigm shift in how cars are powered, connected, and how they will be used. As a part of this, autonomous vehicles will provide a novel opportunity for occupants to disengage from the task of driving and partake in Non-Driving Related Tasks (NDRTs), improving the vehicle experience. The primary aim of the research presented in this thesis is to determine the ergonomic design requirements for a positive journey experience with a highly autonomous vehicle. This was investigated using a mixed methods approach including a global survey, in-depth interviews, a simulator study, and a fitting trial. 

Firstly, a global 42-question online survey of drivers (n=1378) was conducted, followed by in-depth interviews with participants (n=18) judged to be most likely to own an autonomous vehicle. 42% of participants surveyed were identified as likely to own an autonomous vehicle and believed they were safer, would reduce congestion and the risk of accidents. There was also a genuine desire to actively fill the non-driving time by being productive, socialising or partaking in relaxing and leisurely activities. The commuting journey was identified as an important journey, with 50% of participants choosing it as their most likely journey. The findings were captured by generating personas which described different users and their needs such as their views on travelling by car today, how they want to see travelling autonomously in the future, and their views on technology more broadly. ‘Sonia’ was chosen as the lead persona due to participants highlighting that commuting journeys today are not a good use of time and an autonomous vehicle could provide a space to be productive.

A simulator study was then conducted to investigate space utilisation, comfort, well-being, posture, and Non-Driving Related Tasks for a 45-minute commuter journey. The vehicle buck was designed and built to facilitate this with interior dimensions accurate to a production vehicle, using a fully adjustable production seat, steering wheel, and pedals. To fully assess space utilisation, the drivers’ seat was mounted on a bespoke seat frame, allowing it to move and rotate in any direction. Each participant (n=16) took part in three simulated commutes under different experimental conditions, which allowed for various levels of space and design feature access (‘Baseline’ – fixed passenger seat and centre console; ‘Customise’ – passenger seat and centre console removed; ‘Co-design’ – additional supporting features added such as lap tables). Comfort and well-being were assessed with questionnaires at two points during each simulator session. A significant decrease in comfort during the baseline and customise conditions compared to the co-design condition was found (p<0.05 for the backrest and headrest contact area). This is also evidenced by high frequencies of neck flexion being observed (reducing 28% between conditions 1 and 3 for postures held over 10 minutes) – these were partly mitigated by additional design features (lap tables, armrests, item stowage) in the co-design condition. It was clear that more research was needed to improve the journey experience for automated vehicles. The range and frequency of activities were also tracked. Device use was the most frequent activity with mobile phone use decreasing in frequency between conditions (34% in the baseline condition to 22% in the co-design condition). Laptop use increased in frequency (20% in the baseline condition to 46% in the co-design condition). Space utilisation was monitored using a camera which showed laptop users sat 255mm rearwards from the driving position compared to mobile phone users that sat 100mm rearwards of the driving position. 

The simulator study provided a ‘macro view’ of the physical space requirements to fulfil the needs identified within the personas. The final study takes a ‘micro-view’ investigating the seat and workstation design for a low H-point environment. Participants (n=22) took part in a static fitting trial using a bespoke adjustable seat that closely relates to a production automotive seat (matching foam hardness, depths, and material). The seat could be adjusted to any position with only the restriction of seat height. There was a significant difference (p<0.05) in trunk angle (M=21.4° for males, M=17.4° for females) for both male and female participants compared to the previous literature, indicating a more reclined backrest angle and steeper cushion angle. There was also a positive correlation between surface height and armrest height (p<.001), but not armrest height and anthropometry. The work presented in this thesis provides strong evidence that the design of car interiors needs to change to accommodate a new ‘productivity posture’. This includes significant changes to the drivers’ seat to allow for more articulation within the seat back and cushion and the ability to create more space in front of them for NDRTs. Car interiors should also accommodate a broader range of tasks such as working on a laptop, using a mobile phone, or resting. This work also highlights the importance of comfort and how these changes will impact the occupant's safety.