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The continuous improvements in brake technology over the last 20 years for commercial vehicles have shown tremendous results in vehicle safety. The pneumatic braking system has been changed from a system just stopping a vehicle to a system, which controls the total vehicle behavior. Modern braking systems have access to the engine, gearbox and retarder. For vehicle dynamic control in critical driving situation this integration process is a further step of safety improvements for commercial vehicles. The paper will describe the evolution process on brake technology from basic requirements of a braking system and the extensions to a system with additional safety features like ABS, ATC and ESC. The paper explains the vehicle dynamics of tractor/trailer combination and the impact of brake control on stability.

Vehicle and traffic safety improvement is one of the most important targets in the vehicle industry. The introduction of ABS for commercial vehicles, meanwhile standard in various countries, was one of the major safety improvements. This system, based on electronics, sensors and actuators shows what is achievable by controlling brakes of such heavy vehicles at the physical limits under various road conditions. With EBS (brake-by-wire) further safety features are integrated including active access of each wheel brake that allows, independent from the driver to apply the brakes to keep the vehicle stable. Electronic stability control as the overall vehicle control system integrated into EBS leads to a new generation of driver assistance concepts. The concept of Electronic Stability Control (ESC) integrated into EBS, simulation studies of vehicle behavior in critical situations, the control strategies and discussion of test results are the main content of this paper.

Air braking systems for commercial vehicles are undergoing a continuous development and improvement. New technologies like disc brakes and electronic brake control will increasingly be introduced in the next years. Compared to current state-of-the-art brake systems incl. ABS and ASR the EBS systems offer the potential to reduce stopping distances, to improve the brake force distribution and braking stability as well as the brake compatibility of vehicle combinations. Reduced stress for the driver and comprehensive monitoring of the brake system are further safety enhancements. As pure electrical brake control could still find some acceptance and compatibility problem, there will be partial or mixed EBS concepts initially. These will still have pneumatic control of some functions and/or pneumatic backup for the electronic functions. EBS is currently in the final stage of development with field validation in a considerable number of vehicles.