Stated Preference techniques are becoming increasingly popular within the fields of transport planning and management as a means of deriving monetary values which both users and non-users place on the attributes of transport systems. These often include tangible costs and benefits which can be represented to respondents easily in numerical terms (e.g. journey time, travel cost, frequency of service, etc.). There are however other attributes which cannot be expressed and comprehended so easily. Examples are journey time reliability, ride quality of a rail system, and environmental costs and benefits. This paper examines the sensitivity of the results of Stated Preference experiments as to how these Preference experiments as to how these types of attributes are represented to the respondent. Empirical evidence is drawn from a study into the estimation of demand for the Manchester LRT system, and which shows that the form and type of representation does have a significant influence on the outcome of Stated Preference research. The paper also examines the possible reasons for these differences particularly with respect to textual representation of attributes as opposed to those shown pictorially. (A)
Abstract