Loss of focus during safety relevant routine tasks is a very common problem in occupational research.
An example of drivers whose route cannot be altered to make it more exciting are train drivers. The method of finger pointing and calling (FPC) had been in use in Japan for decades. The train operator points at all relevant objects, for instance signals, and says what they see (eg "proceed signal").
A paper by Bhuiyan et al* also explores imaginary FPC. Imaginary FPC is compared to actual FPC with optical tomography of test subjects in a driving simulator. The paper suggests there may be some benefit.
Imaginary FPC is particularly useful to cyclists since we rather not take a hand from the bars in situations where attention is required due to an inherent risk. It is conceivable a combination of actual FPC and imaginary FPC increases your awareness of safety relevant objects and agents whilst cycling.
*Published in IEEE Pulse, May 2016, a peer reviewed journal.