Roads are transportation infrastructure. But roads are also the most abundant form of public space. Residents greet each other along neighborhood streets. Shoppers stroll from store to store along streets, or sit out on sidewalks to eat. Once streets are understood as public spaces, then the importance of designing streets not just for cars, but for people and their activities is apparent. Well-designed streets enable walking and biking as well as transit. Well-designed streets are appointed with pleasing materials and landscaping. Because streets are controlled by the public, governments have wide latitude over their design.
It is important to remember that streets are more than just the carriageway. The public space of the street is defined by the buildings and landscapes abut the road, and so the design of street includes the placement and design of the buildings and landscape elements.