Travel costs are calculated by the usual route. However, if it is not possible by usual route reasons unavoidable natural disaster or other circumstances of the operations is calculated by a route that has actually elapsed.
Travel expenses to calculate the route. However, calculate some routes if business circumstances or natural disaster or other unavoidable reasons could route that actually passed.
I calculate the travel expenses by the regular route. But I calculate it by the route that in fact passed when I can't depend on the regular route for the reason why the circumstances of duties or natural disaster others are unavoidable.