Several studies have shown the effectiveness of on-board monitoring for improving commercial driver safety but little has been done to examine truck drivers' attitudes toward such systems. The purpose of the current study is to examine these drivers' initial attitudes toward an on-board monitoring system (OBMS) as influenced by driver characteristics and driving experiences. Commercial drivers' attitudes and demographics were collected via a questionnaire distributed after a brief introduction of an OBMS. The results of a cluster analysis revealed three subgroups of commercial drivers who had negative, moderately positive, and extremely positive attitudes toward OBMS. Those with extremely positive attitudes, named the Fanatics cluster indicated that they would highly trust the system and felt they would adjust their driving based on system feedback. The cluster with more negative attitudes (named Opponents) showed a higher proportion of non-married drivers than married drivers and reported that the system would be an invasion of privacy. This study provides some insights on commercial drivers' attitudes toward feedback from technology and can help designers and researchers understand differences in drivers' willingness to accept and use feedback systems.