A cooperative adaptive cruise control (CACC) system enables shorter gaps and tighter control of gaps using vehicle-vehicle communication, and the CACC system has significant positive effects on traffic flow in highway system. The study is about an applicable evaluation of human machine interface (HMI) for CACC of trucks using a truck driving simulator (DS) system. A novel truck DS was constructed to reproduce truck dynamics and control by integrating a full-scale cabin of truck into a universal DS system. And a gap distance controller for longitudinal and lateral directions was designed to realize the CACC of trucks. A HMI system prepared for the actual-vehicle CACC driving was used for examine the driver’s acceptance, which is mainly about whether the HMI help driver to realize safe and comfortable CACC driving when the HMI system real-time provides the advanced information service.