The purpose of this paper is to investigate the sources and consequences of mode choice habits in Lausanne, Switzerland, and assess how they can help explain the gaps between current planning tools and actual public transport usage. By analyz-ing combined panel questionnaire and GPS tracking data collected over the course of four weeks from the Panel Lemanique, the paper establishes a human-centric def-inition of mode choice habits from literature and proposes a method for quantifying and characterizing the strength of a mode choice habit anchored in this definition using a Hidden Markov Model. This data is subsequently corresponded with an existing spatial index of network service quality to identify spatial relationships between network service quality and mode choice habits, before finally being used to calibrate a logit mode choice model for Lausanne. The results of these analyses are used as a first step toward understanding the role of habits in closing the gap between planning tools and actual behavior, and to recommend improvements to current planning tools to better account for mode choice habits in future planning decisions.