Elevating Software Quality in Automotive Engineering: The SQIL Approach by Volkswagen

We delve into the SQIL approach, the need for additional criteria beyond Automotive SPICE, insights from leading industry players such as BOSCH and HELLA, and the significance of monitoring software quality trends. By leveraging established methodologies, SQIL ensures a rigorous and structured approach to software quality improvement.

Understanding Automotive SPICE

Automotive SPICE (ASPICE) is a widely adopted framework for assessing and improving software development processes in the automotive industry. It ensures that suppliers follow a structured and quality-driven development process. However, Volkswagen identified areas where additional criteria were needed to enhance software quality further. This led to the development of Konzerngrundanforderungen Software (KGAS) or Group Basic Requirements Software.

KGAS – Strengthening Automotive SPICE

Vehicles today are not just assemblies of individual components but interconnected ecosystems of features and functionalities. A steering system, for example, is responsible for multiple interrelated tasks, such as:

• Sending steering angle data to the Electronic Stability Program (ESP)
• Interfacing with torque vectoring and active damping systems
• Communicating with ADAS for self-driving capabilities

To manage this complexity, Volkswagen introduced KGAS, an extension of ASPICE that provides additional consistency and traceability requirements. Some key requirements include:

• KGAS_3193: All requirements must be evaluated in terms of risks and feasibility.
• KGAS_3247: Requirements must be unambiguous.
• KGAS_3267: Specification of system/software requirements must follow a structured format (IF THEN ).

By enforcing these criteria, KGAS ensures that software development is robust, traceable, and aligned with functional safety standards.

Key Responsibilities of an SQIL

An SQIL is responsible for maintaining software quality across Volkswagen’s supplier network. The primary responsibilities include:

1. Process Quality Assurance – Ensuring compliance with ASPICE and KGAS.
2. Consistency Checks – Verifying the integrity and traceability of requirements, design, and test cases.
3. Monitoring Trends – Using key performance metrics to track development progress and identify areas of improvement.
4. Reporting – Monthly reporting to Volkswagen’s quality department to ensure transparency and continuous improvement.

3. Monitoring Software Development Performance

SQIL reports leverage metrics based on Automotive SPICE Annex D, which defines key performance indicators for software traceability and verification. Some of the crucial metrics include:

• Number of system/software features planned vs. implemented
• Percentage of verified system/software requirements
• Traceability of software components from requirements to test cases
• Cyclomatic complexity analysis for code maintainability

Regular monitoring and trend analysis allow Volkswagen to proactively address potential quality issues before they escalate.

BOSCH AS: Automated Metrics and Reusable Components

BOSCH Automotive Steering Systems implemented SQIL methodologies in Volkswagen’s MQB platform, which significantly streamlined quality tracking. Key strategies included:

• Automating Metrics: The Q-Report was developed to automatically generate traceability and test coverage metrics, reducing manual effort.
• Baukasten (Modular Approach): Standardized system and software functions were developed with reusability in mind, improving efficiency and consistency.
• Safety and Non-Safety Coverage Separation: Separate tracking for ASIL-D (safety-critical) and QM (non-safety-critical) requirements enhanced functional safety assessments.

HELLA: Dashboard-Driven Quality Tracking

HELLA adopted SQIL principles through a dashboard-based quality monitoring system. This approach enabled:

• Monthly tracking of system/software requirement implementation trends
• Process compliance evaluation using ASPICE and KGAS criteria
• Early identification of process deficiencies through consistency checks

By embedding SQIL methodologies into standard project workflows, HELLA ensured compliance with Volkswagen’s rigorous quality expectations.

Volkswagen is further refining the SQIL framework by introducing enhanced dashboard functionalities and expanded documentation requirements. The latest initiatives include:

• Integrating AI-driven anomaly detection to predict potential software defects.
• Aligning with cybersecurity frameworks to enhance protection against automotive cyber threats.
• Extending SQIL to self-driving and cloud-connected functionalities, addressing new-age automotive software challenges.