Service Frequency Standards in Regional Bus Transport: A Comparative Analysis of Passenger Trip Rates in Poland and the Czech Republic

Service frequency is one of the key determinants of public transport attractiveness, yet empirical standards for regional bus services remain poorly defined. This study examines the relationship between the number of daily bus service pairs and regional public transport use using data from Poland and two Czech regions (the Plzeň Region and the Vysočina Region). Public transport use was analysed separately for adults and for children and young people using two original indicators. For adults, the logistic model provided the best fit, revealing a clear saturation effect. Despite substantial differences in the overall level of public transport use, the characteristic service frequency thresholds were remarkably similar across all analysed regions. The identified thresholds corresponded to approximately 4, 8, 12, and 20 daily bus service pairs and formed the basis for a five-level classification of regional bus service standards. For children and young people, the relationship was weaker, and no single functional form clearly outperformed the others. The proposed framework contributes to sustainable regional mobility by linking service provision with observed passenger use and by providing evidence-based reference levels for planning and evaluating regional bus services. The identified thresholds may support the development of evidence-based service standards that improve accessibility and avoid inefficient service provision, providing a practical basis for balancing passenger benefits and the efficient use of public transport resources.