Product line development places emphasis on quality attributes like understandability, maintainability, reusability and variability. Better modularization techniques like aspectoriented programming are supposed to improve these attributes. In the context of an industrial case study in the domain of infrastructure software for toll systems from Siemens AG, Germany, we have investigated how OO designs can be enhanced using AO techniques. We have explored, in particular, how sequential crosscutting concerns can be modularized using AspectJ and how distributed ones can be modularized using AWED, a system that features aspects with explicit distribution. Concretely, we show how sequential and distributed aspects improve the implementation of the charge calculation functionality that is central to realworld tolling systems. General Terms Design, Experimentation, Languages. Keywords Software Product Lines, Aspectoriented Software Dev...