## 5 Simulation Models as a Substitute
### Comparisons of The Simulation Models
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline
**Pros and Cons** & **Factors** & \begin{tabular}{c} **Ship-Handling** \\ **Simulators** \\ \end{tabular} & **MARTRAM** & \begin{tabular}{c} **OFI** \\ **Model** \\ \end{tabular} & **SMARTS** & \begin{tabular}{c} **Istanbul** \\ **Static Model** \\ \end{tabular} & \
\begin{tabular}{c} **MDTC** \\ **Model** \\ \end{tabular} &
\begin{tabular}{c} **CA** \\ **Model** \\ \end{tabular} \\ \hline \multirow{7}{*}{Contributions for Risk Assessment} & Collision Avoidances & \(\surd\) & \(\surd\) & - & \(\surd\) & - & - & - \\ \cline{2-8}  & Considering Extreme Circumstances & \(\surd\) & \(\surd\) & - & - & - & - \\ \cline{2-8}  & Ship & \(\surd\) & - & - & - & - & \(\surd\) \\  & Hydrodynamics & \(\surd\) & - & - & - & - & \(\surd\) \\ \cline{2-8}  & Widely Recognized & \(\surd\) & - & - & - & - & - & - \\ \cline{2-8}  & Considering Ship & - & \(\surd\) & \(\surd\) & \(\surd\) & - & - & \(\surd\) \\  & Traffic Conditions & \(\surd\) & - & \(\surd\) & - & - & - & \(\surd\) \\ \cline{2-8}  & Automatic Behavior & - & \(\surd\) & - & \(\surd\) & - & - & \(\surd\) \\ \cline{2-8}  & Fast & - & \(\surd\) & \(\surd\) & \(\surd\) & \(\surd\) & \(\surd\) & \(\surd\) \\ \cline{2-8}  & Encounter Counts & - & - & \(\surd\) & \(\surd\) & \(\surd\) & \(\surd\) & \(\surd\) \\ \cline{2-8}  & Distribution of Vessel Position & & - & - & - & - & \(\surd\) & \(\surd\) \\ \cline{2-8}  & Distribution of Ship Arrival & & - & \(\surd\) & \(\surd\) & \(\surd\) & \(\surd\) & \(\surd\) \\ \cline{2-8}  & Various Ship Speed & \(\surd\) & - & \(\surd\) & \(\surd\) & \(\surd\) & \(\surd\) & \(\surd\) \\ \cline{2-8}  & Crossing Encounters & \(\surd\) & \(\surd\) & - & \(\surd\) & - & \(\surd\) & - \\ \hline \multirow{3}{*}{Limitations for Risk Assessment} & Human Intervention & \(\surd\) & - & \(\surd\) & - & - & - & - \\ \cline{2-8}  & Time Consuming & \(\surd\) & - & - & - & - & - & - \\ \cline{1-1} \cline{2-8}  & Expensiveness & \(\surd\) & - & - & - & - & - & - \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Comparison of the simulation models. ties [64; 66]. This is true for the simulation models at this stage, as the models are lacking in calibration and verification. The uncertainty would be minimized if the models provide more accurate ship behavior and results. This depends on model development and systematic verification. A worldwide application of ship traffic simulation could help with the process, as ship-handling simulators are widely accepted and applied across the globe. The statistical model does not explain the fact that ships are able to take active evasive behavior to avoid collisions. The simulation models successfully fill in this gap by reproducing vivid ship traffic and various encounter situations as in reality. Although the simulation models have various limitations, we can still look forward to their future developments. This chapter tries to explain the function of the simulation model in safety assessments and gives a clue as to future developments. This section compares the simulation models mentioned in this chapter. Different models have different functions in the risk assessments. The assessments are performed in different geographical locations of the globe, with different purpose. Therefore, comparing the models is not an easy task. This paper only takes the contributions and limitations for risk assessment as factors for comparing the models. There are other factors, such as accuracy, technics, popularity, and worldwide applicability, etc., that are not included. This section introduces the simulation models that perform an indispensable role in the risk analysis models. There are several advantages for the simulation models compared to the statistical models. First, the collision candidates can be generated using random variables derived from AIS data analysis. The underlying uncertainties in traffic formation and collision avoidances can be more realistic compared to the historic data derived from simple statistics.