“…However, many of these studies are not inferential as the one performed here, but descriptive [ 8 , 9 , 25 , 26 , 27 , 28 ], so no statistical inference can be obtained, i.e., their results should not be extrapolated. Among the inferential studies, some of them consider all types of crashes [ 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 ], which is not convenient to our purpose, as we are studying the crashes that can be avoided by “2+1” road transformation. Other interesting studies consider non geometric risk factors, such as driver behavior [ 10 ] or environmental conditions [ 12 ].…”