The need for effective and low-cost ways of facilitating upper limb therapy for individuals recovering from stroke has led to the Driver's Simulation Environment for Arm Therapy (Driver's SEAT). This assistive device is an upper limb one-degree-of-freedom robotic therapy device that incorporates a modified PC-based driving simulator. This paper describes the novel use of a driving simulator to implement an upper limb bimanual exercise task and presents control algorithms that use torque feedback as a method of encouraging the preferential use of one limb over another. The key feature is a split steering wheel, which allows us to measure the tangential forces applied to the wheel by the subjects' impaired and unimpaired upper limbs independently. We present experimental results to show Driver's SEAT's ability to measure bilateral forces and quantify tracking performance.