# Road Safety Management of Uncontrolled Access Points:
## 3 Results and Discussion
### The Relationship between Traffic Accidents and the Radius and Width of the Access
The decrease in radius translates into the conversion of the transition shape from an access point with the right edge which is physically delimited (Distribution 1) to an access point where there are no materialised elements with the function of guiding the entry manoeuvre (Distribution 2). For access points included in this last category, the trend of the accident rate is strictly related to the variability of the width L\({}_{\rm a}\). In addition, (TGI)\({}_{\rm A}\) is increasing with the increase in (L\({}_{\rm a}\)/R\({}_{\rm i}\))\({}_{\rm m}\) and thus with the increase in width (the radius is approximately constant), it is not possible to identify a clear relationship between the two variables. One reasonable explanation for this situation is that the absence of a delimited edge leads the driver not to follow a canalized path, thus he has several alternatives for the entry manoeuvre (greater space, higher perception of freedom in the execution of the turning manoeuvre). For this reason, the crash phenomenon is affected by driver behaviour and this clarifies the dispersion of data in Distribution 2. The slight increase observed in the accident rate of Distribution 2 could be due to the increase in the width of the access point, implying more interference among the vehicle trajectories and thus a higher risk of collision. The transition from Distribution 1 to Distribution 2 exhibits a drastic decrease in both the accident rate (about 40%) and the access width. The safest conditions are related to lower values in both radius and width; this specific condition is attributable to greater control of the driver's execution of the manoeuvre. These findings confirm those of earlier studies: a small radius reduces turning speed and increases the safety level. The collected data are consistent with some design criteria reported in previous studies, which confirmed that roadside configuration affects driver behaviour [22, 49, 50, 51, 52, 53] particularly in rural areas and during night driving [54]. Most research has found that attention and gaze are focused on regions with high expectations of information regarding  
Figure 10: Trends of (L\({}_{a}\))\({}_{m}\) (**a**) and (R\({}_{i}\))\({}_{m}\) (**b**) for each distribution. the activities carried out [55; 56]; in particular, eyes orientations are focused on the edge: the delineation and geometry of the edge affect vehicle position at the entry of horizontal curves [57]. In general, the results found in this section suggest that a well-designed connection transition shape can improve the safety potential of the access point. Measures implemented for the right-hand edge delineation (i.e., road markings, guardrails, reflective delineators) can be an effective solution in the mitigation of access point-related collisions. The selection of the most appropriate access management measure depends on several factors which are strictly related to each specific case analysed (e.g., costs, the limited available area, the traffic conditions, operations, and volumes in the access section). Channelization of the access point may be an effective solution for the management of vehicles turning into or out of uncontrolled accesses with a great width (reduction/elimination of intersecting vehicle paths). Furthermore, channelizing islands as well as right-turn acceleration/deceleration lanes could be useful in the control of both the speed at which the turn is made and the position of the vehicle during the turn.