Despite the development of safety measures and improvements in preventive systems technologies, maritime traffic accidents that involve ships carrying hazardous and noxious substances (HNS) continuously occur owing to increased amount of HNS goods transported and the growing number of HNS fleet. To prevent maritime traffic accidents involving ships carrying HNS, this study proposes an intuitive route risk assessment technique using risk contours that can be visually and quantitatively analyzed. The proposed technique offers continuous information based on quantified values. It determines and structures route risk factors classified as absolute danger, absolute factors, and influential factors within the assessment area. The route risk is assessed in accordance with the proposed algorithmic procedures by means of contour maps overlaid on electronic charts for visualization. To verify the effectiveness of the proposed route risk assessment technique, experimental case studies under various conditions were conducted to compare results obtained by the proposed technique to actual route plans used by five representative companies operating the model ship carrying HNS. This technique is beneficial not only for assessing the route risk of ships carrying HNS, but also for identifying better route options such as recommended routes and enhancing navigation safety. Furthermore, this technique can be used to develop optimized route plans for current maritime conditions in addition to future autonomous navigation application.

Abstract
 1. Introduction
 2. Risk Contour for Route of ShipsCarrying HNS
  2.1 The scope of maritime traffic accidents andrisk of routes by ships carrying HNS
  2.2 The concept of risk contour
  2.3 The purpose and advantage of risk contour
 3. Risk Assessment Technique for Route
  3.1 Determination of route risk factors
  3.2 Designation of route risk assessment area
  3.3 Algorithm for route risk assessment
 4. Result and discussion of the technique
  4.1 Experimental model
  4.2 Result of the route risk analysis
  4.3 Result of the route risk assessment
  4.4 Discussion of the practical applications
 5. Conclusion
 References

• Min-Gi Jeong(Graduate School, Korea Maritime and Ocean University)
• Moon-Jin Lee(Korea Research Institute of Ships & Ocean Engineering/KIOST)
• Eun-Bang Lee(Department of Coast Guard Studies, Korea Maritime and Ocean University) Corresponding author