Wolfgang just sent me another picture (taken by a colleague of him) with more information in the head-up display. It shows a speed of 180 km/h and I wonder who took the picture. Usually only the driver can see such a display ;-)
For assistance, information and entertainment systems in cars (an I assume we could consider taking photos an entertainment task) there are guidelines [1, 2, 3] - an overview presentation in German can be found in . Students in the Pervasive Computing class have to look at them and design a new information/assistance system that is context aware - perhaps photography in the car could be a theme... I am already curious about the results of the exercise.
 The European Statement of Principles (ESoP) on Human Machine Interface in Automotive Systems
 AAM Guidelines
 JAMA Japanese Guidelines
 Andreas Weimper, Harman International Industries, Neue EU Regelungen für Safety und Driver Distraction
(thanks to Wolfgang Spießl for sending the references to me)