Sustainable Urban Transport—Why a Fast Investment in a Complete Cycling Network Is Most Profitable for a City

The development of safe cycling as a mode of transport is an important objective of the transformation towards sustainable mobility in European cities. A significant number of European cities are faced with the need to implement the assumptions of the European Green Deal, of which the promotion of sustainable urban transport is a part. The article presented a simulation of the Perfect Cycling City Model in real conditions that inspired the design of two scenarios for the fast development of bicycle routes in a key transport network area in Warsaw. Scenario 1 assumes building subsidiary bicycle routes and links between the main routes. In Scenario 2, the development of all optimal cycling links at the local level is assumed. An increase in cycling participation is expected in both scenarios. The comparison of projected costs of each scenario indicated that building a complete network of connections is more profitable in terms of increased cycling participation and could counter the dominance of private car use. For this to happen, measures encouraging individuals combined with improved safety and convenience of cycling around the city must be undertaken.