  The capacitated arc routing problem is a very important problem with many
practical applications. This paper focuses on the large scale capacitated arc
routing problem. Traditional solution optimization approaches usually fail
because of their poor scalability. The divide-and-conquer strategy has achieved
great success in solving large scale optimization problems by decomposing the
original large problem into smaller sub-problems and solving them separately.
For arc routing, a commonly used divide-and-conquer strategy is to divide the
tasks into subsets, and then solve the sub-problems induced by the task subsets
separately. However, the success of a divide-and-conquer strategy relies on a
proper task division, which is non-trivial due to the complex interactions
between the tasks. This paper proposes a novel problem decomposition operator,
named the route cutting off operator, which considers the interactions between
the tasks in a sophisticated way. To examine the effectiveness of the route
cutting off operator, we integrate it with two state-of-the-art
divide-and-conquer algorithms, and compared with the original counterparts on a
wide range of benchmark instances. The results show that the route cutting off
operator can improve the effectiveness of the decomposition, and lead to
significantly better results especially when the problem size is very large and
the time budget is very tight.
