Street Network Design for a Sustainable Mobility System

An urban network's shape and characteristics can have high influence on many mobility aspects, such as travel distance, mode choice and safety. For example, can a tram be a real competition to the car? Definitely yes if the car is stuck in a traffic jam and the tram has priority, but not only in such case! With a proper system design a tram may offer a faster travel to the city centre than the car. On the other hand if the tram provides faster travel than the car only during several peak hours, it is usually enough to provide better service for a majority of people travelling in such direction.For intense on-street public transport networks full priority is not always possible. This is another reason to resign from a paradigm of providing public transport along major car arteries – the urban public transport will be more efficient, also in speed terms, when it will be closer to commuters. Such closeness means a decrease in segregation, so part of the paper will be dedicated to theoretical calculations and practical observations of allowable tram and bus speeds on city streets.Safety leads to a problem of homogeneity of streets’ technical class and of coherence between streets’ functional and technical classes. Data from both Poland and other countries shows, that such elements as traffic intensity and extend of traffic segregation should strictly coincide with proper technical parameters. It is problematic, since many European streets, for historical reasons, cannot be rebuilt to fully meet uniform standards of one class, so results of inquiries on how to make these standards adjustable without compromising safety or living quality will be presented.Concluding, the aim of this paper is to gather experience gained from theoretical calculations and practical designs, and present a street network as a system. A system that properly implemented allows for sustainable, efficient and safe mobility. A system that to some extend is adjustable to local historical conditions. A system that, unfortunately due to local pressure and political reasons, is often overridden, with sober consequences. The investigations were focused on specific locations, but strengthened with theoretical calculations and generalised allowing for wide implementations.