# Interface Design for Responsible Remote Driving: A Study on Technological Mediation
## 4 Interface Design Analysis
### Physical Feedback  
The fact that regular drivers perceive physical forces while moving around in their vehicles is so familiar that it almost passes unnoticed. Differently from seeing and hearing, being capable of perceiving forces and factor this information in while driving is not an object of specific tests, measurements, or legal requirements. It is simply presupposed as a factual component of the driving experience. As such, it definitely contributes to providing information to drivers essential for the exercise of safety and responsibility [16; 54]. Indeed, various physical sensations experienced while travelling inside a vehicle support SA and responsible driving: the push of acceleration, the pull of (sudden) brakes, vibrations and bumps caused by potholes or poor road surface, centrifugal thrusts during turns, and so on. Integrated with visual and auditory information, physical feedback helps drivers make sense of traffic situations and navigate them responsibly. According to their characteristic amplification/reduction structures, both visual and auditory HMIs set aside physical forces. However, it is once more important to stress that exclusions such as this one do not carry any considered judgment on the relevance of the excluded information. On the contrary, reductions just result from the mere process of technological mediation. It is therefore critical to raise awareness on what remains excluded from given instances of technological mediation and carefully evaluate whether the silenced information is actually significant and, thus, should somehow be retrieved. Given the responsibility-enhancing potential contained in physical feedback, it is advisable to provide HMIs for its transmission to ROs. Physical feedback information that could be relayed on to ROs is multifarious and includes sensations that mimic the feeling of acceleration, braking, turning, incline, and road surface texture [43; 55]. It has already been mentioned how difficult it is to provide effective cues to ROs for determining acceleration, breaking, and speed. Indeed, it is difficult to accurately judge vehicle speed and stay engaged in the driving task without force feedback pushing drivers back into their seat or vibrations from the friction of the ties on the road. If ROs lack the correct perception of these aspects, they might easily end up operating abrupt maneuvers and engage in behavior that would worsen driving fluidity. Moreover, a lack of road surface feedback would reduce the RO's ability to detect possibly dangerous pavement imperfections such as bumps and cracks. Lack of centrifugal feedback makes the experience of turning--already complicated by vision-related reductions--much more abstract and unfamiliar, while events such as skidding on, e.g., icy roads would become hard to detect. Furthermore, disembodiment or physical disconnectedness appear to lie at the heart of the already mentioned risk of disengagement and less attentive driving due to an overly gamified driving experience, in which ROs struggle to remain conscious of the material repercussions of their actions. Physical feedback seems especially important in urban environments, where sharp turns in busy streets, frequent acceleration and deceleration driving patterns, obstacles like manholes or potholes, and adverse weather conditions such as rain or snow are frequent and significantly impact on responsible driving. For all these reasons, physical feedback would help ROs controlling vehicles more safely through city streets. Apart from capturing environmental information, force feedback could also be used to convey alarms and warnings without burdening the already taxed sense of sight. In a way, easily recognizable vibrations signaling danger could be thought of as an amplification of goosebumps, keeping ROs engaged and watchful in risky scenarios. For example, vibrating alerts can signal obstacles or lane drift.