## 4 Discussion
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{\(v\) (km/h)} & \multirow{2}{*}{**Site ID**} & \multicolumn{3}{c}{_Effective Geometry_} & \multicolumn{3}{c}{_Geometrical Limits_} & \multicolumn{1}{c}{_Verification_} \\ \cline{3-7}  & & _h (cm)_ & \(i_{a}\) (\%)_ & \(i_{e}\) (\%) & \(R_{v\,min}\) (m)_ & \(i_{max}\) (\%) & \(i_{max}\) \textgreater{} Average (\(i_{a}\); \(i_{e}\)) \\ \hline \multirow{9}{*}{30} & site 14 & 5.06 & 3.36 & 3.55 & & 2.09 & no \\  & site 6 & 7.56 & 8.17 & 3.56 & & 2.56 & no \\  & site 12 & 7.66 & 8.22 & 7.88 & & 2.57 & no \\  & site 18 & 8.19 & 8.95 & 10.58 & & 2.66 & no \\  & site 11 & 8.24 & 8.09 & 6.77 & & 2.67 & no \\  & site 7 & 8.65 & 6.27 & 4.02 & & 2.73 & no \\  & site 10 & 8.99 & 6.96 & 6.59 & & 2.79 & no \\  & site 13 & 9.03 & 3.90 & 4.97 & & 2.79 & no \\  & site 9 & 9.84 & 6.61 & 5.93 & 115.75 & 2.92 & no \\  & site 8 & 10.00 & 7.73 & 5.07 & & 2.94 & no \\  & site 15 & 10.18 & 8.17 & 9.41 & & 2.97 & no \\  & site 19 & 10.36 & 9.96 & 10.74 & & 2.99 & no \\  & site 17 & 10.85 & 9.36 & 8.65 & & 3.06 & no \\  & site 16 & 11.14 & 12.10 & 8.94 & & 3.10 & no \\  & site 2 & 16.44 & 2.68 & 2.19 & & 3.77 & yes \\  & site 4 & 20.16 & 5.84 & 5.94 & & 4.17 & no \\  & site 3 & 21.45 & 2.65 & 2.78 & & 4.30 & yes \\ \hline \multirow{9}{*}{40} & site 23 & 4.47 & 5.89 & 7.75 & & 1.47 & no \\  & site 20 & 5.19 & 5.27 & 6.10 & & 1.59 & no \\  & site 5 & 5.41 & 9.75 & 9.72 & & 1.62 & no \\  & site 22 & 5.43 & 8.50 & 6.12 & & 1.62 & no \\  & site 21 & 5.93 & 8.25 & 6.56 & & 1.70 & no \\  & site 24 & 8.59 & 6.98 & 9.67 &The regulation implementing the Italian driving code [49] provides geometries of features that are permitted on residential roads and living streets, but they are banned on lifelines. Table 8 lists the geometric constraints of a trapezoidal speed table. The longitudinal profiles obtained from limits in Table 8 allowed for the calculation of \(a_{uzz}\) using the full car model: Table 9 summarizes the results. The comparison between the values of \(a_{uzz}\) obtained from surveys and calculated for speed tables highlights that two RPCs (i.e., site 1a and site 1b) do not comply with geometrical and dynamic criteria for speed tables (Table 10). \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{\(v\) (km/h)} & \multirow{2}{*}{**RPC**} & \multicolumn{2}{c}{\(a_{uzz}\) (m/s\({}^{2}\))} \\ \cline{3-4}  & & **Surveyed RPCs** & **Designed Speed Table** \\ \hline \multirow{8}{*}{30} & site 2 & 0.70 & \\  & site 3 & 0.93 & \\  & site 4 & 3.13 & \\  & site 6 & 3.54 & \\  & site 7 & 2.37 & \\  & site 8 & 3.62 & \\  & site 9 & 4.06 & \\  & site 10 & 3.46 & \\
30 & site 11 & 3.89 & 6.06 \\  & site 12 & 4.18 & \\  & site 13 & 2.02 & \\  & site 14 & 1.77 & \\  & site 15 & 4.50 & \\  & site 16 & 4.86 & \\  & site 17 & 4.67 & \\  & site 18 & 2.79 & \\  & site 19 & 5.68 & \\ \hline \multirow{8}{*}{40} & site 1a & 4.26 & \\  & site 1b & 4.18 & \\  & site 5 & 3.64 & \\ \cline{1-1}  & site 20 & 3.90 & \\ \cline{1-1}  & site 21 & 3.42 & \\ \cline{1-1}  & site 22 & 4.12 & \\ \cline{1-1}  & site 23 & 3.08 & \\ \cline{1-1}  & site 24 & 3.80 & \\ \hline \hline \end{tabular}
\end{table} 
Table 10: Values of \(a_{uzz}\) on the surveyed RPCs and on the designed speed tables. Figure 19: Example of speed table. \begin{table}
\begin{tabular}{c c} \hline \hline \(v\) (km/h) & \(a_{uzz}\) (m/s\({}^{2}\)) \\ \hline
20 & - \\
30 & 6.06 \\
40 & 4.14 \\
50 & 1.98 \\ \hline \hline \end{tabular}
\end{table} 
Table 9: \(a_{uzz}\) values caused by a speed table. The following observations were made concerning the collected data and the adopted criteria:  
* For a given value of \(h\), RPCs designed with the geometric criterion imply lower values of \(L_{t}\) than ones designed with the comfort criterion.