# Road Safety Management of Uncontrolled Access Points:
## 3 Results and Discussion
### The Relationship between Traffic Accidents and the Radius and Width of the Access
For each class, the average accident rate (TIG)\({}_{\rm{A}}\) is estimated as follows:  
\[\rm{(TIG)_{A}=\frac{10^{8}\cdot\sum\limits_{i=1}^{n}N_{i}}{\sum\limits_{i=1}^{ n}M_{i}}} \tag{7}\]  
where n is the number of elementary sections within the single class (n is the access density of the i-th class). Table 9 shows the definition of the classes and the characteristic values of the parameters obtained for each class. (\(\rm{L_{a}/R_{i}}\))\({}_{\rm{m}}\) is the average value of the class. The relationship between (\(\rm{L_{a}/R_{i}}\))\({}_{\rm{m}}\) and (TGI)\({}_{\rm{A}}\) is displayed in Figure 9. The graph shows that the function can be divided into two distributions; this separation allows the description of the relationship between (\(\rm{L_{a}/R_{i}}\))\({}_{\rm{m}}\) and (TGI)\({}_{\rm{A}}\) through different causes and explanations. The second distribution is identified by low values of (\(\rm{R_{i}}\))\({}_{\rm{m}}\); more specifically, for these points, the mean value of radius is always lower than 0.5 m. Distribution 1 is characterised by values of (\(\rm{R_{i}}\))\({}_{\rm{m}}\) higher than 2 m. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline  & **Classes (\(\rm{L_{a}/R_{i}}\))** & **(\(\rm{L_{a}/R_{i}}\))\({}_{\rm{m}}\)** & **(\(\rm{L_{a}/R_{i}}\))\({}_{\rm{min}}\)** & **(\(\rm{L_{a}/R_{i}}\))\({}_{\rm{max}}\)** & **\(\sigma\) (\(\rm{L_{a}/R_{i}}\))** & **(\(\rm{L_{a}}\))\({}_{\rm{m}}\)** & **(\(\rm{R_{i}}\))\({}_{\rm{m}}\)** & **(\(\rm{Med_{i}/10^{8}}\))\({}_{\rm{m}}\)** \\ \hline \multirow{4}{*}{**TIG**} & \multirow{4}{*}{**TIG**} & 1 & \(<\)2.45 & 1.49 & 0.23 & 2.41 & 0.56 & 17.18 & 14.65 & 8.63 \\  & & 2 & 2.45–4.89 & 3.45 & 2.49 & 4.82 & 0.69 & 18.06 & 5.41 & 8.55 \\  & & 3 & 4.90–10.00 & 6.58 & 5.18 & 9.72 & 1.15 & 17.56 & 2.74 & 8.96 \\  & & 4 & 10.01–15.00 & 12.25 & 10.22 & 14.50 & 1.47 & 29.40 & 2.38 & 11.51 \\ \hline \multirow{4}{*}{**TIG**} & \multirow{4}{*}{**TIG**} & 5 & 15.01–20.00 & 16.74 & 15.97 & 18.00 & 0.88 & 5.67 & 0.35 & 6.86 \\  & & 6 & 20.01–30.00 & 25.45 & 20.35 & 30.00 & 3.22 & 8.88 & 0.36 & 8.21 \\  & & 7 & 30.01–40.00 & 35.10 & 30.20 & 40.00 & 2.98 & 8.64 & 0.24 & 12.53 \\  & & 8 & 40.01–50.00 & 44.79 & 40.50 & 50.00 & 3.11 & 8.96 & 0.20 & 8.01 \\  & & 9 & 50.01–60.00 & 54.85 & 50.15 & 60.00 & 3.02 & 11.98 & 0.22 & 12.60 \\  & & 10 & 60.01–70.00 & 65.24 & 60.40 & 70.00 & 2.92 & 13.05 & 0.20 & 10.38 \\  & & 11 & 70.01–80.00 & 75.17 & 70.40 & 80.00 & 2.67 & 15.03 & 0.20 & 10.59 \\  & & 12 & 80.01–90.00 & 84.11 & 80.25 & 90.00 & 2.91 & 16.82 & 0.20 & 17.82 \\ \hline \hline \end{tabular}
\end{table} 
Table 9: Values of \(\rm{L_{a}}\), \(\rm{R_{i}}\), \(\rm{L_{a}/R_{i}}\) and (TGI)\({}_{\rm{A}}\) obtained for each class. Figure 10 reports the trend of (L\({}_{\rm a}\))\({}_{\rm m}\) and (R\({}_{\rm i}\))\({}_{\rm m}\) for each distribution. The comprehensive analysis of the findings allows us to draw the following considerations on the correlation between (L\({}_{\rm a}\)/R\({}_{\rm i}\))\({}_{\rm m}\) and (TGI)\({}_{\rm A}\):  
1. for access points with a curved radius greater than 2 m (Distribution 1) and width (L\({}_{\rm a}\))\({}_{\rm m}\) which does not vary between classes ((L\({}_{\rm a}\))\({}_{\rm m}\) is 17.18 m, 18.06 m, and 17.56 m for the classes 1, 2, and 3, respectively), the accident rate is approximately constant. For the above-mentioned classes, there is a decrease in (R\({}_{\rm i}\))\({}_{\rm m}\) from 14.65 m to 2.74 m; (R\({}_{\rm i}\))\({}_{\rm m}\) is 2.38 m for class 4. This condition reveals that for access points in Distribution 1 the safety level is more affected by radius variability; more specifically, the decrease in radius is correlated with the increase in the risk of accidents. Furthermore, it can be assumed that (TGI)\({}_{\rm A}\) increases when the radius is lower than 5 m which is the recommended value for the radius by some studies [48]. 2.