The purpose of this research is to discover what factors encourage someone to sell during Car-Free Day in Indonesia. By using an explorative quantitative method, data collection was carried out through interviews with 40 s and questionnaires given to 450 s in nine major cities in Indonesia. The results of the interviews in the Stage 1, ten factors were found that encourage someone to sell on Car-Free Day. The results of Stage 1 then became questionnaire inputs, where the sampling method was purposive distribution. The results of the study show that the ten factors examined through the factoring process can be reduced to four factors. These factors are leisure activity, marketing, legality and public participation. The dominant factor that drives someone to sell on Car-Free Day is the consumer factor, or the existence of prospective buyers. The implications of these findings are explored.