In response to the Japan Social Development Fund’s (JSDF) objectives, the northeastern region of Thailand was selected as the Thailand Community Youth Helmet Use project’s implementation site by GRSP. Apart from being geographically the largest and most populated area in Thailand, the northeastern region is also economically the poorest. The situation analysis, monitoring and evaluation component (SME) of the project aimed to provide: (1) baseline project information, (2) an input to project review, (3) insights on aspects of project implementation, and (4) information on project outcomes and impacts. This report emphasizes the lessons learned from the summative assessment. A controlled before-after design was applied to facilitate the establishment of baseline information and the summative evaluation.