Traditional market plays an important role in ancient urban life, especially in heritage cities such as Casbah, Algiers. Some traditional markets however are frequently criticized as inconvenient for users and consequently not well used. Improving performance of traditional markets is therefore a critical issue faced by the city planners and designers. Conventional model, which is described mainly in respect of maximum user’s capacity or service radius is inadequate to give an account of the issue, hence a new theoretical model is needed for both research and operational purposes.