Since the early 1980s, the number of more complex systems and the use of microprocessors, particularly in passenger cars, has increased significantly. Various comfort and safety functions were first introduced at that time in high-end vehicles. Many of these functions, such as ABS or on-board diagnostic systems, are now part of the technical standard. To enable these functions, various components such as sensors, control units, and actuators must communicate with one another. For this purpose, an increasing number of data lines have been installed and ever more complex architectures have been developed. In aircraft construction, work on bus systems began significantly earlier, enabling various nodes to communicate via only a few bus lines. This made it possible to significantly reduce the number of data lines and thus the associated weight.

The CAN bus is probably the most widely used bus system in modern vehicles. As shown in the figure below, additional bus systems have been developed over the past three to four decades for special tasks in industry and the automotive sector.

Approximately 15 years after the development of the CAN bus, work began on a more cost-effective variant in the form of the LIN bus, which was introduced in 2002. The LIN bus (Local Interconnect Network) is characterized by its simplicity and low cost. It is mainly used for less complex applications such as the control of comfort systems (e.g., power windows or seat adjustment).

However, with the increasing complexity of vehicles and the emergence of safety-critical systems, it quickly became clear that more powerful bus systems were required. FlexRay, introduced in 2006, was developed specifically for safety-relevant applications such as X-by-wire systems (e.g., brake-by-wire). FlexRay is characterized by a high transmission rate and deterministic behavior, enabling reliable real-time communication.

In 2008, Automotive Ethernet followed, which was originally used for infotainment applications. Compared to previous systems, Automotive Ethernet enables significantly higher bandwidths and plays a crucial role in modern vehicle architectures, particularly with regard to connected and autonomous driving.

In 2012, CAN-FD (Flexible Data Rate) was developed and incorporated into ISO 11898-1:2015 in 2015, representing a further development of the classic CAN bus. CAN-FD enables higher data transmission rates and more efficient communication in order to meet the increasing demands of modern control units.

With CAN-XL, a future standard, further optimization of the CAN bus is currently underway. CAN-XL is intended to provide even higher data rates and additional functions to meet the requirements of the next generation of vehicles.

Despite strong competition in the field of bus systems, particularly in terms of transmission rates, CAN will in all likelihood remain the de facto standard for communication between simple control units for the coming decades. Even though many manufacturers (such as VW and Tesla) increasingly use zonal architectures that require high-speed connections between main control units, it can be expected that simple control units, such as those for power windows, will continue to be implemented using the CAN bus. Even highly modern vehicles such as the ID.7, the Tesla Model Y, or the Audi A5 use it for comfort functions.