Choice model calibrated on current behavior predicts public response to new policies

The standard approach to predicting public response to possible changes in transportation policy is to describe the changed environmental conditions in a scenario and ask individuals what their choice would be. These stated intentions tend to mislead policy makers in the absolute sense because of the varying degrees of overestimation. Sophisticated attribute choice models which are calibrated in terms of the stated intentions also tend to be weak predictors of actual public response to new policies. Empirical research is presented in which a logit model that is calibrated using the attribute ratings of the alternatives under the new policy conditions described in the scenario in relation to current behavior rather than stated intentions provides highly accurate predictions of the actual ppublic r eaction to neew policies. (a) (TRRL)