“…After excluding a further 37 articles for various reasons, 27 articles met the inclusion criteria. The primary reasons for excluding studies were as follows: the collected data was based on speed limits or speed zones only [24][25][26][27][28][29][30], the data was limited only to head impacts [31] or ground contact injuries [32], no injury or fatality data was used [33,34], the inability to compute an S-shaped risk curve [35][36][37][38][39][40], the study data was a subset of another included study [41][42][43][44][45][46], the collected data consisted of only fatal cases [47][48][49], the original full-text of the study was unavailable [50][51][52], the study was not focused on frontal impacts [53][54][55], the study used experimental data [56,57], the impact speed was not measured or included [58,59], and Full-text articles excluded, with reasons (n = 37)…”