4.2. Discussions
Legs 4W and 12E have long been well recognized as the geographical chokepoints of the Straits of Malacca and Singapore. This is because the two legs represent the narrowest point with only 1.2 miles wide shipping lane with 5′, “degree of acceleration >0.9″, and “number of ship domain (r = 0.4) overlaps >300″ as risk criteria. We can also use other risk criteria to identify the risky legs since the relative safety levels of various legs are obtainable based on the three risk indices.