D Growth of literature on driver monitoring

The survey of Section 3 provided an initial set of 56 references for the field of DM. They appear in Table 2. Our overall analysis and synthesis of the field led us to examine in detail a total of 254 references, including the 56 initial ones. They all appear in the “References” section.

To characterize, in an approximate way, the evolution of the number of publications on DM over recent years, (1) we computed, for the 56 initial references, the number of them published during each of the years they cover, and (2) we did the same for the 254 examined references. Figure 4 gives the corresponding graphs, or histograms, of “number of references vs year”. Each histogram shows a significant growth over the last 10 years or so. The significant dip in 2020 could be an effect of the difficult worldwide situation during that year.

(a)	(b)

Figure 4: Graph (a) is the histogram of the number of references vs year for the 56 initial references on driver monitoring (DM), and graph (b) is the corresponding histogram for the 254 examined references. These histograms suggest that the field of DM has been the object of growing interest over the years and, in particular, over the last 10 years.