Requirements management for Automotive projects

Łukasz Stachowiak

Functional Safety Engineer

What is requirements management? 

Requirements management is an iterative set of activities that enables the delivery of a complete product description that meets the needs and expectations of customers and internal or external stakeholders, regarding every step which needs to be performed during the requirements development process like elicitation, evaluation, documentation, or refinement. Therefore, requirements management is an especially important topic in the automotive industry. The reason behind this is very simple – automotive requirements management process has its own list of very strict requirements.  

Proper management of requirements gives more benefits the greater the complexity of the project is. In any case, please don’t miss the point: proper requirements management process is always a legitimate approach, especially if you consider how often a real complexity is underestimated or it is just impossible to estimate it correctly.  

Why manage requirements? 

The answer to that question seems obvious and, in my opinion, it is  – requirements management simply pays off. Besides a long list of advantages like improvement of quality, decreasing risks, or enabling effective scope management, it is also necessary to take into consideration the disadvantages. 

However, what may seem at first glance like the biggest weaknesses, for example  unnecessary additional effort or increase of costs, turn out to be advantages because  at the end of day requirements management brings cost and time reduction, especially in the automotive word. The crucial thing is to adjust the requirements management plan to project needs and limitations. 

What does requirements management mean to the automotive industry? 

A significant part of the automotive products has combined various types of features that could be related to safety. From the requirements perspective, it means an increase of complexity level, additional processes that need to be achieved and of course a new branch of the requirements to create – safety requirements.  

The safety requirements are defined for risk reduction. It is associated with additional required activities like additional traceability structure, safety attributes management. Furthermore, the automotive quality process requires a number of artifacts that need to be created and maintained in terms of requirements engineering as well. 

What are the safety-related requirements types and attributes? What about traceability? 

When developing an automotive product, it is emphasized that the vehicle meets the safety requirements, but it is just the thin end of the wedge. The creation of a proper tailored requirements management process can help during the whole product lifecycle development process.  

One of the first steps which are necessary to take is to determine the requirement type. It is a technique that enables the creation of a hierarchy of requirements with a cascading relation between different abstraction layers. The variety of requirement types should be adjusted to project needs; however, it can be assumed with some degree of certainty that the following distinction will work for most safety-related applications: 

  • Functional, 
  • Nonfunctional,  
  • Stakeholder, 
  • Functional Safety, 
  • Technical Safety, 
  • Business, 
  • Interface, 
  • Component. 

Each type of requirement describes its own scope. Based on that, the definition of a product from a different perspective is done. However, requirements can be distinguished and structured not only by "type”.  

An integral part of the requirements are attributes, which are used to precisely define characteristics of a particular requirement. The total number of used attributes depends on project scope, level of complexity and specialisation diversity involved in a project. The exemplary attributes that could be emphasised are: 

  • ID, 
  • Category, 
  • Discipline, 
  • Feasibility, 
  • Safety, 
  • Version, 
  • Planned Release. 

A proper attributes definition constitutes a strong basis for a traceability chain. In relation to the standards as well as Automotive SPICE and Automotive Functional Safety standard - ISO 26262, required traceability and suitable artifacts are determined, but neither of those standards provides information on how to plan and implement traceability in practice. Thereupon, adjusted requirements management plan gives a space to tailor it to owns needs.  

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What are the best requirements management tools in Automotive? 

Undoubtedly during the development of a serious project, it is crucial to maintain requirements with respect to traceability and change version in a structured way. Manual coordination of the living complex structure sounds impossible even for one person, not to mention the whole team. That’s why these market gaps have been quickly filled with dozen of various tools which can support and maintain a significant part of the requirements dependencies.  

As usual, the best tool depends on a particular purpose of use, so for sure there is no just one good answer. Although in the end, besides concrete arguments, the final choice depends on personal habits and preferences as well. 

Requirements management planning: best practices to ensure the requirements plan is a success 

The key is to avoid surprises. Ensure to implement requirements management as early as possible for example in your strategy planning and make sure that every dependent competence is aware of the importance of requirements management. For obvious reasons, there is no possibility to anticipate every possible dependency which can happen in a project, so it is a very wise approach to prepare a requirements management plan ready for iterative evolution during a product lifecycle.  

Certainly, there is a number of benefits, which requirements management brings to both project and organization, but the most crucial is to remember that requirements management is for help and support. An unsuitable approach could bring overwhelming bureaucratic limitations, which can be counterproductive.