I once worked on a user interface for passenger use in military vehicles and field testing similarly showed that hardware buttons were superior. I wasn't even a driver interface so glanceability was not the issue, it was the improved haptics and being able to differentiate buttons by touch in a moving vehicle.
Given the added cost of physical buttons, the compromise was a series of physical buttons along the edges of the screen.
One technique used to convince stakeholders that the added cost was worth it: have them sit an an office chair and ask them to complete tasks on each prototype while someone holding the back of their chair occasionally jerked it around to simulate vehicle movement. Never had objections from anyone who went through one of those presentations.
Given the added cost of physical buttons, the compromise was a series of physical buttons along the edges of the screen.
One technique used to convince stakeholders that the added cost was worth it: have them sit an an office chair and ask them to complete tasks on each prototype while someone holding the back of their chair occasionally jerked it around to simulate vehicle movement. Never had objections from anyone who went through one of those presentations.