The modal split is one of the most important attributes of any city’s transportation policy. Obtaining knowledge about it, requires conducting detailed surveys carried out on large groups of respondents, using a travel diary. But even simplified surveys can be an important factor in evaluating efforts to change transportation behavior. The paper discusses transport mode choice surveys, conducted in Krakow, in 2013–2023, as part of the full and supplementary Comprehensive Travel Studies and different simplified surveys carried out in Krakow. A comparative analysis of the methodology of the types of surveys, as well as the survey results themselves, was carried out, with particular attention to the magnitude of errors in estimating the percentage of use of public transport and the personal car in travel. As a result of the analysis, general principles for the planning of transport mode choice surveys were presented, aimed at increasing the usefulness of the survey results.