Abstract-The continuous advancements of embedded computing and communication technologies are pushing several engineering systems toward increased levels of autonomy. A remarkable example is that of cooperative active safety systems currently being developed by government and industry consortia. While these systems promise a future in which transportation will be safer, more enjoyable, and more efficient, they also pose a great design challenge to the control, communication, and computer science communities. That is, safety must be guaranteed by design despite these systems are multi-agent, partially physical and partially computational, and involve human operators. In this paper, we focus on the problem of safe design in the presence of human operators and employ a formal hybrid control approach. We illustrate our results on an in-scale multi-vehicle roundabout test-bed.