# Driving Behavior Classification and Sharing System Using CNN-LSTM Approaches and V2X Communication
## 4 Performance Evaluation
### Effectiveness of Prediction Result Sharing  
The effectiveness of driving behavior sharing to surrounding vehicles was evaluated via simulation. The simulation environment consists of a straight road of ~5 km, with a ego vehicle and a target vehicle. A ego driving vehicle is a vehicle that uses ACC to follow speed while maintaining a safe distance from the target vehicle. A target vehicle is a vehicle whose driving behavior changes over time into defensive, normal, and aggressive behaviors. The proposed behavior sharing system is applied to both the ego vehicle and the target vehicle, and the target vehicle shares its own driving behavior through V2X communication, and the ego vehicle receives the target vehicle's driving behavior. The safe distance must be set so that the ego vehicle does not collide even if the target vehicle \begin{table}
\begin{tabular}{c c c c c} \hline \multicolumn{2}{c}{**Test: Urban road**} & \multicolumn{3}{c}{**Output Label**} \\ \hline
**Input: 5 s** & **Networks** & **Defensive** & **Normal** & **Aggressive** \\ \hline \multirow{6}{*}{Defensive} & 1D-CNN & 89.72\% & 9.8\% & 0.48\% \\  & 2D-CNN & 92.64\% & 6.67\% & 0.69\% \\  & LSTM & 91.58\% & 1.72\% & 6.69\% \\  & CNN-LSTM & 81.7\% & 18.19\% & 1.17\% \\  & 4 CNN-LSTM & 94.62\% & 5.38\% & 0.0\% \\  & 4 CNN-2 LSTM & 94.14\% & 5.82\% & 0.05\% \\ \hline \multirow{6}{*}{Normal} & 1D-CNN & 36.52\% & 60.04\% & 3.44\% \\  & 2D-CNN & 3.44\% & 93.86\% & 2.69\% \\ \cline{1-1}  & LSTM & 71.54\% & 6.29\% & 22.18\% \\ \cline{1-1}  & CNN-LSTM & 10.87\% & 87.97\% & 1.17\% \\ \cline{1-1}  & 4 CNN-LSTM & 2.63\% & 97.1\% & 0.27\% \\ \cline{1-1}  & 4 CNN-2 LSTM & 1.5\% & 97.82\% & 0.69\% \\ \hline \multirow{6}{*}{Aggressive} & 1D-CNN & 5.11\% & 9.88\% & 85.01\% \\  & 2D-CNN & 1.71\% & 16.27\% & 82.01\% \\ \cline{1-1}  & LSTM & 38.56\% & 2.84\% & 58.60\% \\ \cline{1-1}  & CNN-LSTM & 0.31\% & 6.67\% & 93.02\% \\ \cline{1-1}  & 4 CNN-LSTM & 0.31\% & 1.5\% & 98.19\% \\ \cline{1-1}  & 4 CNN-2 LSTM & 0.03\% & 1.12\% & 98.85\% \\ \hline \end{tabular}
\end{table} 
Table 7: Confusion matrix of urban road driving behavior classification results in simulation. \begin{table}
\begin{tabular}{c c c c c} \hline \multicolumn{2}{c}{**Test: Highway**} & \multicolumn{3}{c}{**Output Label**} \\ \hline
**Input: 5 s** & **Networks** & **Defensive** & **Normal** & **Aggressive** \\ \hline \multirow{6}{*}{Defensive} & 1D-CNN & 92.46\% & 7.02\% & 0.52\% \\  & 2D-CNN & 97.3\% & 2.68\% & 0.02\% \\  & LSTM & 92.58\% & 4.56\% & 2.87\% \\  & CNN-LSTM & 93.59\% & 6.41\% & 0.0\% \\  & 4 CNN-LSTM & 95.02\% & 4.91\% & 0.07\% \\  & 4 CNN-2 LSTM & 99.48\% & 0.45\% & 0.07\% \\ \hline \multirow{6}{*}{Normal} & 1D-CNN & 30.91\% & 65.45\% & 3.64\% \\  & 2D-CNN & 2.45\% & 97.28\% & 0.28\% \\ \cline{1-1}  & LSTM & 62.86\% & 19.35\% & 17.79\% \\ \cline{1-1}  & CNN-LSTM & 21.28\% & 78.51\% & 0.21\% \\ \cline{1-1}  & 4 CNN-LSTM & 4.4\% & 95.17\% & 0.43\% \\ \cline{1-1}  & 4 CNN-2 LSTM & 0.73\% & 99.21\% & 0.06\% \\ \hline \multirow{6}{*}{Aggressive} & 1D-CNN & 3.04\% & 6.95\% & 90.01\% \\ \cline{1-1}  & 2D-CNN & 0.42\% & 0.22\% & 99.36\% \\ \cline{1-1}  & LSTM & 14.6\% & 8.8\% & 76.60\% \\ \cline{1-1}  & CNN-LSTM & 0.51\% & 2.88\% & 96.61\% \\ \cline{1-1}  & 4 CNN-LSTM & 0.13\% & 0.38\% & 99.49\% \\ \cline{1-1}  & 4 CNN-2 LSTM & 0.0\% & 0.06\% & 99.94\% \\ \hline \end{tabular}
\end{table} 
Table 8: Confusion matrix of highway driving behavior classification results in simulation. suddenly brakes [46]. Here, we add a variable called safety factor that serves to change the safe distance according to driving behavior. The safety factor can be set manually, and when the safety factor is 1, a safety distance equal to the default safety distance is assigned. As defensive behavior is the safest driving behavior, a default safety distance is assigned by setting the safety factor to 1. To provide an additional safety distance as the aggressiveness increases, we set the safety factor to 1.1 for normal behavior, and 1.3 for aggressive behavior.