With some of the modern drivers it doesn't take much to get their attention to wander. One of my favourites was the old fashioned equivalent to these boxes with the ear plugs. How can you concentrate with allsorts going into your brain and how can you hear such as ambulances, fire engines and police cars.
I think I have mentioned it before: when Volvo came up with advertising about their super safe cars. The accident rate went up because idiot motorists took it as some form of safety device that compensated for their incompetence.