Retrofit as a Module Driver: Enabling Circular and Service-Oriented Vehicle Architectures

The climate emergency has prompted the European Green Deal, triggering far-reaching circular-economy legislation for road vehicles. Emerging directives - most notably the draft End-of-Life Vehicle Regulation - tighten material-recovery quotas and favor business models in which manufacturers retain ownership of their fleets. As a result, the Mobility as a Service (MaaS) business model is becoming increasingly important for the automotive industry, significantly impacting vehicle design and modularization strategies. Unlike the conventional paradigm, which prioritizes personalization and initial purchase decisions, MaaS vehicles experience intensified usage patterns, leading to accelerated aesthetic and haptic degradation of user-facing components. Consequently, product architectures must increasingly take into account simplified maintenance and refurbishment strategies to maintain high perceived quality over prolonged operational lifespans. Current modularization methods, however, do not explicitly address these requirements. To bridge this gap, this paper introduces Retrofit as a dedicated module driver, extending the established catalogue guiding early-stage modular product structuring. Retrofit refers to the systematic capability of exchanging or renewing modules within a vehicle, particularly focusing on swift renewal of interior surfaces and components that rapidly deteriorate under high utilization, thereby safeguarding perceived quality and residual value. To illustrate this concept, the paper presents a case study of an automotive seat module. Seats represent a critical interface for user comfort and vehicle perception, making them ideal for demonstrating retrofit-driven modularization. Using this example, the study shows how Retrofit facilitates rapid, cost-effective replacements and refurbishments of wear-prone interior modules, contributing to improved fleet operability and sustainability. The findings underline Retrofit’s strategic role in future automotive product architectures, emphasizing the need for automotive manufacturers to adapt modularization strategies accordingly. Integrating Retrofit as a module driver aligns automotive products with the evolving economic, environmental, and operational objectives of MaaS business models.