Prior to the widespread adoption of the internet and the availability of inexpensive screens, passengers occupied themselves by sleeping, listening to music, looking out the window, chatting with neighboring passengers, eating, reading, shopping via catalog, writing, or playing games. On some modes walking around was also permitted. The introduction of airplane in-seat radio channels increased the availability of diversions. The further advance of movies on airplanes (and later buses), first shown to the whole cabin, and later individualized for passengers with their own seat-back screen provided one additional source of diversion for passengers.
Despite the work environment on modes like airplane or bus, especially in the confined spaces of coach, by the late 1990s, passengers also started bringing their own laptop computers, portable DVD players, and later tablets, on-board as an additional tool to enable personalized work and entertainment.
One of the major advantages of being a passenger rather than a driver is the ability to do anything other than driving while traveling. That means travel is not necessarily the lost time that transportation professionals have long treated it as (Lyons and Urry 2005). With the rise of the Internet, and especially the mobile phone, people are expecting to have access to electronic devices (and the internet) for work and play wherever they go. One of the last areas of blackout, the airplane during takeoff and landing, may soon see some relaxation of restrictions (Bilton 2013). Airlines have introduced on-board Wi-Fi (at a high charge) to take advantage of this demand.
If our predictions about the future consisting of the "end of driving", we then have the "rise of the passenger". We can model in-vehicle behavior in the future as following the trends of passenger behavior on transit, trains, buses, and planes. People will find a way to divert themselves. We can further envision vehicle makers facilitating this, especially in the interim stages between no-automation and full automation.
My view is that the windshield becomes a transparent heads-up display suitable for entertainment, but see-through so that should the driver need to retake the wheel, the driver still has visibility. This would extend the technology now widely available in airplanes to the passenger dashboard, and replace all that technical mumbo-jumbo with what people want: transparent cat videos.
Bilton, Nick (2013) FAA May Loosen Curbs on Fliers Use of Electronics. New York Times http://bits.blogs.nytimes.com/2013/03/24/disruptions-f-a-a-may-loosen-curbs-on-fliers-use-of-electronics/
Lyons, Glenn and John Urry (2005) Travel Time use in the Information Age. Transportation Research A 39 (2-3) pp. 257-276