By tradition, transport appraisal relies primarily on travel time savings and monetary values. Assessment tools rarely factor in the perspective of travellers in terms of their subjective travel experience while on the move. Worthwhile travel time introduces the idea that travel can be pleasant, meaningful or worthwhile and not exclusively associated with the economic utility of the activity at the destination of the trip and the work-related productivity during the trip. This paper explores how the "worthwhile use of travel time" can be conceptualised and unpacked, so that it can be adequately captured and integrated into transport appraisal practice. We reviewed the literature on worthwhile travel time and perceived travel experience in psychology, economics, public health and travel behaviour research and we formulated the conceptual framework of worthwhile travel time that is grounded on the traveller's perception of three forms of value emerging from existing literature: enjoyment, productivity, and health. Our conceptual framework of worthwhile travel time suggests that experience factors (i.e. travel conditions as experienced by the traveller) can enable travel activities (i.e. the trip itself or activities on-themove), which in turn unlock the values of enjoyment, productivity and fitness that influence the perceived worthwhileness of a trip to a different degree each. Additional (explanatory) factors such as the door-to-door trip characteristics, the traveller's personal characteristics and attitude, and the spatial and temporal conditions can also influence the perceived worthwhileness of a trip. On a policy level, the integration of the worthwhile travel time concept into transport appraisal practice could allow future transport investments to offer a better balance between reduced travel times and improved quality and experience of a trip for the traveller.