I'm a PhD student and have recently submitted a proposal for research about driver mental fatigue especially among truck hauling driver in coal mining in Indonesia. I am curious about various methods of measuring mental fatigue for these drivers.
the gold standard metrics are the Karolinska Sleepiness Scale for subjective fatigue and the PVT for neurobehavioral measures
Please contact me on this. We are working on the same subject and have a technology that does this but needs some hard contextual measurement data.
www.nfocusdriver.com
If you want a continuous measure of mental fatigue during prolonged driving you can use the various high and low frequency bands of Heart Rate Variability. It is a relatively new technique to use the higher and lower bands but I used it with some success. See attached file. There is also fNIRS which is a new technique but not validated yet. There are other options such as skin conductance, EEG, and heart rate.
Thesis An Investigation into Control Mechanisms of Driving Performa...