Safety and comfort applications are addressed using Driver Assistance (DA) systems like Adaptive Cruise Control (ACC) system using Long Range Radar (LRR) or Short Range Radar (SRR) or both. Novel waveforms and functionalities applied to next generation DA multi-sensor systems and their corresponding complex algorithms require advanced digital hardware supporting high computation rate and severe real-time constraints. In this paper, we present a flexible FPGA-based architecture for digital control and signal processing of a DA system. The considered DA system makes use of a new particular waveform to enhance capabilities of old generation ACC radar. Hardware/software partitioning has been explored in order to match the real-time requirement of the system. Development steps, from algorithm specification to on-board demonstration, are detailed. Promising results in terms of resources use and execution time are shown using a prototyping board with a single Virtex-II Pro device.