Enterprises as well as private households exploit multi-sourcing strategies that lead to
fragmented material flows and multiple deliveries. Often, customer (unloading) sites are
visited several times by different vehicles of a transport service provider. In order to avoid
costly setup at business customer sites and with the goal to increase the probability to meet
a private customer in a first delivery attempt it is necessary to coordinate the multiple visits.
In this context moveable time windows (also called implicit time windows) are proposed as
coordination tool. In contrast to explicit time windows, a moveable time window does not
restrict the customer visiting time to a certain part of the time axis but it only limits the time
differences among the necessary unloading operations at a certain customer site. The prima-
ry goal of the here reported research comprises the evaluation of impacts on least distance
vehicle routes and on the number of required vehicles implied by the consideration of im-plicit time windows from the perspective of a carrier company. We report about simulation
experiments.