Effective Collision Diameter and Collision Rate of Ship

Effective collision diameter, D, is calculated from number of collisions on three congested waterways, Uraga Suido, Akasi kaikyo, and Kanmon kaikyo, using a simplified equation, [numerical formula] where P, ρ, and V_ are the collision rate, the density, and the relative speed respectively. This equation is deduced from the general equation introduced by the author by assuming the lengths of all ships are equal. The collision diameter thus obtained is 0.4〜1.8×10^<-4>L for collision of ships going in one direction and 1〜3×10^<-4>L for collision of ships going in opposite directions. These values allow estimation of collision rate on fairways where traffic quantity and distribution of ship size and density are known.