Within a freight transport context, the origin-destination distance and the weight of the shipment play an important role in the decision of the most preferred transport service and in the way logistics managers evaluate the transport service’s attributes. In particular, the attributes commonly used in order to describe a freight transport service in a stated choice framework are cost, time, punctuality and risk of damages, respectively. This paper investigates the role of origin-destination distance and weight of freight transport services introducing a conditioning effect, where the standard utility function is conditioned on the freight transport distance. The particular model proposed is a heteroskedastic panel multinomial logit (panel H-MNL) model where the heteroskedastic influence that conditions each ‘traditional’ utility expression is captured through a dummy variable distinguishing between short/medium-distance and long-distance freight transport services. Results show that the heteroskedastic effect conditioned on long-distance transport has a negative impact on the marginal utility for a hypothetical alternative describing a freight transport service. The reduction in the marginal utility experienced for long-distance transport is moderated by the weight of the transported goods as well as by the interaction of the conditioning effect with time, punctuality and damages attributes. The two models proposed outperform the underlying basic model and suggest that an appropriate conditioning effect leads to an improved understanding of the derived measures, such as measures for marginal rates of substitution.