As part of the ongoing development and change in the demand patterns for public transport, the County of Calw is required to review and upgrade the county wide public transport system. We were tasked with conducting a county wide public transport user survey of 1700 daily trips on 64 bus lines covering an area of c.a. 800 km² to assess the current demand level and determine deficits and improvement potentials. Each individual boarding / alighting passenger at individual bus stops was counted with parallel passenger interviews conducted onboard by our staff. We proceeded to digitize the entire public transport network for the county of Calw and were able, using the information obtained from the survey, to calibrate a public transport demand model. This allows the county to make informed decisions on future demand patterns and study the effects of changes in the supply on the entire system significantly saving on resources and avoiding trial and error planning methods.