Our research examines emerging sensing and control technologies that enhance safety. The SAFETRUCK tractor testbed (Navistar 9400 series heavy duty tractor equipped with electronically controlled engine, transmission, and anti-lock brakes and traction control) has been outfitted with appropriate computer, power, communication, and safety and control subsystems. In the event of the driver losing control (due to fatigue, etc.), we will demonstrate on a highway the ability of the system to intervene and steer the tractor-trailer testbed to the next safe shoulder and bring it to a stop. Our purpose is to demonstrate technology that can prevent road departure accidents. A "virtual bumper" concept is under development for providing a protective envelope around the vehicle. Encroachments by other vehicles into this region result in appropriate combinations of steering, braking and throttle adjustments so that the vehicle can steer out of an imminent collision. This is particularly important for large trucks which, due to their weight, may not be able to stop quickly enough. We will build upon our previous successful simulations by designing and incorporating sensing based on DGPS and radio transmission to facilitate a series of experiments demonstrating the concept on the SAFETRUCK testbed interacting with two other vehicles.