We describe the integration of two pairs of force displays-- a force-feedback wheel (FFBW) and the S c haire (`Share Chair'), a rotary motion platform-- in a dual- driver networked driving simulator which navigates through virtual space using CVE ( collaborative virtual environment) groupware. We developed a double-driver (long ladder-style) fire-truck simulation with a tiller (rear steering), driven via an integrated pair of networked driving simulator stations. Such a dual-driver system is useful to turn narrow corners rapidly and smoothly in case of (simulated) emergencies. Its FFB steering wheels display simple collision force to both drivers separately when the vehicle collides with walls or other vehicles. The technique of feeding back the effect employs programs using C++ and DirectInput, escaping to an execution file called Force- Manager from the driving simulator, which is implemented with Java3D. Effect patterns are changed by arguments to ForceManager. The S c haire is rotated with a servo- motor, the rotation angle controlled via internet through the CVE. A demonstration video is posted at http: //sonic.u-aizu.ac.jp/spatial-media/ Videos/DualDrivingSimulator.mov . Keywords: dual-driver networked driving simulator, force feedback, haptic interface, rotary motion platform.