- We describe the algorithms we have developed to automatically generate street networks and building plots in the automatic procedural creation of a realistic city. Our system first sites the important regions of a city, such as the commercial center, historical center, and residential areas. Then, a network of freeway and main roads are built. Finally, a network of streets are built throughout the city. The main contribution described in this paper is the design of the freeways, main streets and minor streets, and the allocation of space for the roads and buildings in the city. Compared to existing methods, our system creates cities that more closely mimics real-world cities, and can also generate millions of streets in seconds.