Unmanned ground vehicles (UGVs) are autonomous robots capable of performing tasks through self- navigation and decision-making. They have the potential to replace humans in dangerous driving scenarios. However, UGVs must be viewed as trustworthy to be accepted, and like any automation, they can make mistakes that decrease human trust in them. Trust repair strategies can mitigate the consequences of trust violations, but they are not always effective. To better understand their effectiveness on UGVs, we designed a between-subjects study examining promises on a UGV’s trustworthiness. Preliminary results showed that promises had a marginal impact on overall trustworthiness but were influential in repairing benevolence but not ability or integrity. These findings have implications for the design of UGV’s and trust repair theory.