This paper introduces a framework for the interactive solving of optimization problems and presents an interactive tabu search algorithm for the pick-up-and-delivery problem with time windows (PDPTW). The framework for the development of interactive algorithms is based on the idea of activating and deactivating constraints in the model of the problem under consideration. We start with an introduction to interactive problem solving and suggest an algorithmic framework. Next we focus to vehicle routing and scheduling applications. There we discuss the demand for interactive approaches, since established local search methods fail to produce reasonable solutions. Our idea is to support them by interactive manipulations. Therefore, we present a recent tabu search algorithm for the PDPTW. We demonstrate several possibilities for human interactions by means of an additional tabu list.