Planning for cycling: are current transport models fit for purpose?

Cycling provides a sustainable alternative to motorised transport by reducing emissions and traffic fatalities, which underscores the need for strategic interventions that include both infrastructure investments and non-infrastructure measures such as polices and regulations to effectively promote cycling. To support this, it is essential to have accurate models incorporating key factors driving both transport and non-transport cycling decisions. This paper presents a summary of factors influencing cycling and evaluates their integration into current cycling models. The review spans both cycling-specific models and large-scale transport planning models, examining how well they account for transport and non-transport cycling. The paper underscores the importance of including non-transport trips in models, yet the review highlights the limited number of studies that do so and the frequent lack of distinction between transport and non-transport cycling, despite the significant share of non-transport cycling in many regions. There is a gap between factors influencing cycling and those used in current models, particularly in incorporating individual attitudes, preferences, and motivations – which are especially influential in cycling. The study highlights the challenge of multicollinearity, where correlations between factors like infrastructure and land use make it difficult to isolate the individual effects of each variable on cycling behaviour. This paper calls for a shift towards collecting longitudinal cycling data and conducting before-and-after studies to better isolate the factors influencing cycling behaviour, which could significantly enhance the accuracy and applicability of cycling models in infrastructure planning.