## 3 Literature Review
### Liability and Safety Standards for Highly Automated Vehicles
Another area where the lack of clear guidelines is evident is in the design of DVIs. These interfaces are critical in allowing interactions between the user and the system to be both safe and efficient. Poorly designed DVIs may increase the risk of safety because they obscure the driver's ability to either understand warnings or react promptly. An illustrative example is the potential liability of manufacturers in the event of an accident caused by an inadequately designed interface. In these cases, the fault could lie in the interface design itself, which can lead to confusion or driver error. [PERSON] et al. [45] show how poorly designed interfaces, particularly about the layout of elements, can impair driver performance and increase the risk of accidents. Studies in this area have revealed significant differences in reaction times, lane departures and other key safety parameters, highlighting the crucial role that interface design plays in influencing driver behaviour. A system that customises an interface by changing some of its features, such as text size, without considering any limitations on the driver's visibility, could be the cause of an accident. In this case, the manufacturer could be held liable for violating safety rules related to the user interface. [PERSON] [46] puts in evidence how, in the EU, the Product Liability Directive (PLD) [47] and the Artificial Intelligence Regulation (AI Act) [48] highlight that an automated driving system must ensure not only technical safety but also a user-centred design which facilitates effective supervision. If a driver fails to respond promptly to a warning due to a poorly designed interface, the manufacturer may be held responsible for failing to meet public safety expectations. However, if the DVI design complies with European standards, it will be necessary to demonstrate that the design choices did not meet minimum transparency or auditability requirements before liability can be attributed to the manufacturer [46]. On the other hand, driver liability comes into play only when the driver has given informed consent and fully understands the risks associated with automated driving. As [PERSON] et al. [49] point out, if information regarding risks and liability is inadequately conveyed through unclear or inappropriate digital interfaces, the driver's consent may be invalidated, raising questions about their own responsibility. If the driver accepts the risk of certain customisations whose effects are not fully understandable, this entails liability on the part of the manufacturer, who could be held guilty of lack of transparency by not having provided the driver with all the necessary information. In this case, the driver's informed consent could be invalidated through violation of the principle of transparency. Finally, it is unrealistic to consider liability as something separate between the manufacturer and the driver, as both parties usually share part of the burden. This is particularly true when a technical fault is compounded by human error. [PERSON] and [PERSON] [50] argue that a lucid and crystalline legal framework can help deal more appropriately with the concept of shared responsibility. For example, if the personalised interface does not clearly signal the need for immediate manual intervention, debates on contributory negligence could arise. The confusion resulting from the lack of notification may lead to a complex attribution of responsibility between driver and manufacturer. Researchers propose a conceptual framework that specifies when a human driver could be held responsible due to contributory negligence in relation to an automated system. Their approach differentiates the operating mode of the vehicle into three separate modes: test, autonomous, and supervised, with criteria for liability shifting between the human operator and the automated system in various circumstances. This framework endeavours to explain when a party should be compelled to bear liability under specific conditions to ensure fairness and consistency within legal outcomes.