Sensitivity analysis of traffic efficiency in restricted channel influenced by the variance of ship speed

Abstract

Enhancing the traffic efficiency of restricted channels is one of the most important objectives for maritime transportation, especially in busy waterways and ports. In many cases, the variance of ship speed would impede the traffic efficiency in restricted channels where overtaking between ships is not allowed. The ship behaviors in restricted channels are studied in this article. Two indicators are applied to evaluate traffic efficiency, which are the percentage of ships that reduce speed and the increase of navigating time in the channel due to speed reduction. Screening method is introduced to make sensitivity analysis considering five factors, which are the mean value of ship speed, variance of ship speed, channel length, safety distance and arriving rate. The results indicate that the mean value of ship speed is most sensitive to traffic efficiency, followed by the variance of ship speed and arriving rate. The safety distance is the least sensitive to channel efficiency. Quadratic equation models and response surface method are further used to make interaction analysis between the factors. High degree of interactions among the mean value, variance of ship speed, arriving rate and channel length are identified. These findings are valuable for the guidance of making effective measurements to make full use of channel resource to promote its efficiency.