A plethora of shared fleet services have been introduced in cities worldwide. Despite their increased presence in urban areas, it is insofar unknown what are the main determinants of travellers’ choices between the usage of shared-mopeds and cars and thereby the extent to which shared moped can substitute car travel. To this end, we design and conduct an SP choice model experiment. The estimated Panel Mixed Logit model is applied to explore the potential market share for shared moped, car and bike under several scenarios which are devised based on the expert interviews. Our findings demonstrate that the return availability of shared moped is the most influential travel time attribute. Walk time from home to the shared moped is an influential factor for people without moped experience. Moreover, model estimation results show that people who have used a shared moped before value the attributes differently than people without previous moped experience. We specifically focus on choice determinants and policy measures targeting car users to facilitate desirable behavioural changes. We present results from model application to demonstrate the effect of different policy packages on the market share of each mode, showing that certain policy interventions can attract car users to switch to shared moped while avoiding a strong reduction in bike use.