Measuring the effects of a new bridge on traffic flows. Railway and car passengers crossing the river Lek near Vianen, before and after the opening of a new additional bridge / effects of the new bridge on traffic streams / means of transportation / time of leaving home / destination / frequency of travel / working hours / parking facilities / use of car for job / car pooling / use of alternative transportation / traffic jams / travel allowances / possession of car, drivers licence / car drivers passengers / railway passengers route and class satisfaction / use of car by members of family. Background variables: basic characteristics/ residence/ household characteristics/ place of work/ occupation/employment/ income/capital assets/ consumption of durables