The design and implementation of effective transport policies to reduce car use in urban areas requires a deep comprehension of the factors that influence travel behavior. In this context, psychological factors play an important role in explaining travel-related decisions. The purpose of this paper is to present a study on the effects of cognitive, affective and behavioral attitudes towards the use of walking and cycling on both intentions and real use of cars, public transport, bicycles, and walking. The data used was obtained from an on-line survey carried out in 2017. Analyses included reliability and validity of the questionnaire, exploratory and confirmatory factor analyses, and structural equation models. Results indicate that cycling and walking are evaluated differently in terms of feelings of freedom, pleasure, and relaxation. Positive evaluation of elements related to past walking behavior are negatively associated to both the intention to walk and actual walking. Transport policies to encourage cycling should be different from those with the aim of promoting walking. Positive attitudes towards walking are not enough to increase real walking.