# Simulation Study on an ICT-Based Maritime Management and Safety Framework for Movable Bridges
## 5 Methodology
### Measures for Collision Prevention
#### 5.3.3 DSRC Control Establishment  
At the Emergency Belt, the DSRC control system is given authoritative power over the ship control system. It can directly stop the ship's operating speed to zero to prevent the probable collision between ship and bridge. This system is generally deactivated for the regular ships incoming and outgoing of the bridge. When a ship comes too close to the movable bridge when the bridge is still not prepared for evacuation, safety command is transferred to ships by DSRC. At the same time, Emergency Belt DSRC control is activated. Two buoys \(\text{B}_{\text{EA}}\) and \(\text{B}_{\text{EC}}\) are placed within the Emergency Belt to detect the position of any ship that is about to enter an Emergency Belt. If a ship enters the Emergency Belt ignoring the DSRC safety command, its position is detected by the buoy at the Emergency Belt and forwards a signal to the bridge control system. At this point, the bridge control system takes over the ship's operating speed control system. The system determines what the operating speed of the ship is. If the ship is not moving, it is evident that it is waiting for bridge evacuation to end. This security technique diminishes any remaining probability of collision between a ship and a movable bridge. Algorithm 1 shows the algorithm for the DSRC based collision prevention system using safety messages and emergency control.  
```
forBa = Activateddo  Checking value for \((k-l)+(m-n)\) if\((k-l)+(m-n)=0\)then  Turn Bridge Open else forBa = Activateddo  Checking value for \((k-l)+(m-n)\) if\((k-l)+(m-n)0\)then  DSRC = Activated  Command = \"Stop the ship before Emergency Belt\"  Send Command to ships via DSRC  end for forBae= Activateddo ifShip velocity 0 then  DSRC = Activated  DSRC takes over the control of ships  Operating ship speed = 0 else  No action. No fine.  end if  end for  end for  end for
```  
**Algorithm 1** Algorithm for DSRC Clash Avoiding Control System  
Operating at greater than the suggested speed at the Emergency Belt is considered a dangerous act. If a collision occurs, it can result in major structural damage and causalities. Excess speeding after the Emergency Belt is considered as a ship operator acting aggressively. As a result of such a dangerous act, financial penalties through the form of a fine are recommended to dissuade ship operators from performing such aggressive acts.  
In another case, the ship that was stopped before the Emergency Belt, according to the DSRC safety message, may still pass the Emergency Belt and get detected by the Emergency Belt buoy. This can occur due to the inertial speed of the ship being too high at the time of receiving the DSRC message. Even after a ship's operating speed begins to reduce, it often takes time to completely stop and will still move due to the previous speed range factor and the loads carrying the ship. As the ship's operating speed is zero, the DSRC control will not detect any operating speed, and DSRC will not interrupt in that case. Thisis considered safe in this system, and ships will get sufficient distance of Emergency Belt as breaking distance. Ships will neither be considered aggressive nor be fined in such circumstances. For the ships needing higher braking distance, a larger Emergency Belt distance needs to be implemented according to this research.