With the rapid development of sensor and computing technologies, personal vehicles are now capable of collecting voluminous information on vehicle status and the road environment, as well as making proximity estimates and predicting potential driving events. Recent advances in vehicle automation have envisioned future driving without the need for drivers to attend to the road. With these trends in vehicle technology for the driving task, a shift in information communication is taking place from driver-roadway interaction to driver and in-vehicle display interaction. • Compared to (SAE) Level 2, drivers under Level 3 automation were less accurate in logo identification, likely due to a reduced number of glances to on-road signs.
Despite decades of research on in-vehicle notification display designs, the majority of studies have concentrated on presenting information related to the driving task, such as display of collision warnings and navigation information. There is little knowledge on how to effectively present information that is secondary to driving but important for a trip, such as notifications of a rest area and local businesses. This information is conventionally presented on a guide or logo sign. Furthermore, existing research on in-vehicle information presentation during highly automated driving has only focused on safety critical messages such collision warnings. These studies do not necessarily generalize to notifications that are trip-related but non-safety critical information, as driver attentional processing could differ depending on the degree of relevance of the notification to the driving task and under various levels of automation.
This project examined the influence of in-vehicle dynamic message displays of trip-related but non-safety critical information on driver visual behavior and driving performance, as compared with conventional on-road guide or logo sign use, during manual and highly automated driving. To achieve this goal, we first conducted a literature review on the following topics: (1) advances in content and update rates of in-vehicle trip-related messaging, (2) driver interaction with autonomous vehicle technology, (3) driver alertness and information processing, and (4) human factors issues in design of driver notification systems. The research team also performed two empirical studies using the NCSU advanced driving simulator, with the first experiment (E1) examining how drivers respond to messages posing various information loads during manual driving and the second (E2) investigating driver responses to messages when driving with high-level automation.
Our findings support the use of in-vehicle displays, especially in combination with on-road signage.
Under manual driving:
- Driver reactions to road hazards were slower when logos were present but the number of collisions did not increase.
- The use of in-vehicle displays produced better vehicle control with comparable workload and visual distraction, as compared to on-road signage.
- Simultaneous in-vehicle and on-road displays showed a benefit on hazard negotiation (fewer collisions).
- Some age differences were observed in driving and visual behaviors, but the evidence does not suggest any particular age-related safety concerns.
When driving with partial automation (level 2):
- Simultaneous in-vehicle and on-road displays led to the highest logo identification accuracy and little impairment of hazard negotiation when logos were present.
- Simultaneous in-vehicle and on-road displays led to shorter single off-road glance durations and mitigated the effect of information load on driver visual processing. Drivers made fewer but longer glances to on-road signage, as compared to in-vehicle displays.
- Older drivers were less accurate in logo identification than young and middle-aged drivers. However, all three age groups showed comparable driving performance, glance durations, and number of glances.
When driving with conditional automation (level 3):
- Compared to (SAE) Level 2, drivers under Level 3 automation were less accurate in logo identification, likely due to a reduced number of glances to on-road signs.