Abstract
Author proposed a model to determine the lane width at straight and one way traffic route as the function of the traffic volume, considering the reliability for strandings. The model was based on the distribution of ship's tracks which were derived from the statistical analyses of traffic surveys by Radar at nallow channels in Japan. According to this analyses, the tracks were normally distributed and the standard deviation could be expressed by a regression equation of lane width and traffic volume on the route. The width of the lane on the model was determined under the condition that the tracks within ±κσ of the distribution lie within the traffic lane. Standard normal variate κ was found in the table of upper probability integrals of the normal distribution, using probability P that the tail of the distribution of ship's tracks protruded out of the traffic lane. We can obtain the probability P from the formula (3) in this paper under the condition that probability which no stranding will occur during t years equals a certain predetermined level. F in the formula shows the probability that lead a ship to stranding actually within the probability P. And the value of F was estimated at 10^<-2> by means of statistical analysis of accident and traffic surveys at nallow channels. It would be capable for us to evaluate the required width of traffic lane as the function of the traffic volume according to this model.
