## 4 Advanced In-Vehicle Displays
### Advanced Display Technologies  
Advanced Driver Assistance Systems are being developed to offload some cognitive demands from drivers to vehicle automation. Many vehicles now include visual status displays to support drivers in automated driving tasks. Since it is difficult to predict where a driver will be looking at each moment, the type and amount of information to display, as well as presentation formats, remain open questions. For example, Head-Up Displays (HUDs) are being integrated in vehicles as part of a current trend in vehicle engineering [69; 70]. These displays present information on the windshield of the vehicle so that it is within the driver's field of view as they gaze at the roadway [71]. For automated driving, HUDs are being considered for presenting important trip-related information [72]. These displays have shown promise in reducing eyes-off-the-road and are more effective than Head-Down Displays (HDDs) in the presentation of navigation and safety information [73]. However, a major issue is such displays can consume driver attention to exclusion of the roadway, even though the road scene is generally within the visual field [59; 70; 74; 75]. In a recent study of the effectiveness of HUDs in automated driving [70], researchers measured driver situation awareness when viewing driving videos with and without an HUD. It was found that not only increasing complexity in a HUD impaired driver situation awareness, but also that driver situation awareness was in general better when there was no HUD. It is perhaps not surprising that when much information was augmented (i.e., complex condition), drivers became cognitively overloaded, and their attention was consumed by the display. However, even under the minimal condition when only road signs and traffic lights that required an action was augmented, driver situation awareness was still poorer than the no HUD condition. Considering a stop sign or a red light which require an action would be safety-critical information, the lack of benefit of HUD as found in this study further alarms the need to investigate how to present trip-related, but non-safety-critical, information to drivers using advanced in-vehicle displays. Research should investigate how to design the HUD, and very importantly, also consider how drivers will become used to visually process such advanced displays. Thus far, there has been little work done to test the effectiveness of advanced information displays for the presentation of trip-related road sign information during automated driving.  
Multi-modal warnings are another type of display that are becoming increasingly prevalent in automated vehicles. They provide a viable solution for delivering information to the driver related to a takeover request, where the driver must re-establish situational awareness on the vehicle and roadway environment [76]. There is a growing body of work investigating how best to combine modalities of information presentation for more effective driver alerts and understanding how perceived urgency can affect driver response times during takeover [56; 77; 78]. General findings indicate that response time for drivers was better in conditions where alerts were pictorial versus text-based and when the perceived urgency of the alert was greater. However, these results were observed when a threat was present in the roadway, resulting in a takeover request from a vehicle to a driver. There has been little work on how multimodal warnings affect driver processing of non-safety-critical information, such as signage for food and lodging.