In many traditional industry applications, such as automotive, process automation and manufacturing automation, software plays a crucial role as an enabler for the introduction of new functionality and retaining competitiveness. The system and software architecture plays an important part in ensuring the systems’ qualities. However, the design of the architecture may be neglected during system development, whilst development efforts are centered on implementing new functionality. The architecture is supposed to support and enable key quality attributes such as safety, reliability, maintainability and flexibility, and so on. This thesis identifies some of the key issues in architecting these software intensive systems. In total, 21 issues have been identified; examples of these issues are (1) there is a lack of process for architecture development, (2) there is a lack of method or model to evaluate business value when choosing architecture, (3) there is a lack of clear long-term architectural strategy, and (4) processes and methods are less valued than individuals’ knowledge and competence. Through a series of workshops, root causes were identified for a selection of these issues. Based on these root causes, five success factors were identified. The success factors are (1) define an architectural strategy (2) implement a process for architectural work (3) ensure authority for architects (4) clarify the business impact of the architecture and (5) optimize on the project portfolio level instead of optimizing each project. In an attempt to provide a possible solution to some of the issues, a method has been created to evaluate how new functionality is successfully integrated into an existing architecture. The method is a combination of the Architecture Tradeoff Analysis Method, ATAM, and the Analytical Hierarchy Process, AHP. The method firstly supports a structured way of listing system goals, and secondly, it also supports design decision-making. Since several issues relate to the organization and are affected by management, a comparison was made between the view of management and architects. This study revealed that one cause for the lack of focus on architecture could be that the existing performance measurement systems used by management all focus on the later phases of development when the architecture is already set.

The amount of electronics in vehicles is growing quickly, thus systems are becoming increasingly complex making the engineering of these software intensive systems more and more difficult. In particular, an architecture supporting the business goals is a prerequisite for successful design.

In this thesis two case studies have been made including three automotive companies with purpose to investigate the key issues related to real-world decisions when developing Electrical and Electronic (E/E) system architectures in the automotive industry.

The results show that many of the identified issues relate to non technical areas such as organization, process, methods and tools, and management. Examples of identified issues are the deficient understanding of the electrical system and software at management level, and the lack of a specific process for architecture development. To cope with these issues we suggest the following actions: Educate management, increase the use of structured decision making, improve the architecture development process, clarify responsibilities in the organization and clarify development strategies.

As a possible solution to one of the suggested actions we have developed a method to evaluate how new functionality is successfully integrated into an existing architecture. Themethod is a combination of the Architecture Tradeoff Analysis Method, ATAM, and the Analytical Hierarchy Process, AHP. The method firstly supports a structured way of listing system goals, and secondly, it also supports the making of design decisions.