In April 2012 an invitation letter was sent to all private households that purchased a new passenger car in November or December 2011, and the same letter to all households who bought an electric car in 2011. Electric car buyers were over sampled to obtain a reasonable group size. The letter included information about the study that involved two online questionnaires. The first questionnaire included questions related to car purchase, and the second consisted of questions about car use. The same psychological constructs were measured in both questionnaires and the electric car buyers received the same questions as the normal car buyers