Although streets also function as public spaces, they are primarily a means of transportation. Urban places have street systems which allow pedestrians, bicycles, motor vehicles and transit vehicles to move safely and efficiently between destinations. Suburban street systems are designed exclusively for motor vehicles, with the result that other modes of transportation are seldom used. These goals can be achieved by adhering to the following principles:

• Interconnected streets: When streets are connected to one another, distances between destinations are as short as possible, making walking much easier. Bus services are also easier to implement, since buses can serve all destinations without "backtracking". Although interconnected streets carry some through traffic, it can be reduced on quieter streets through the use of traffic calming (see traffic calming, below). Interconnected streets work just as well in a gridiron system as in an organic system, although organic systems provide more obvious locations for commercial centers.

• Sidewalks: Where sidewalks are absent, pedestrians are at a greater risk of being hit by vehicles, and are made to feel like second-class citizens. In nearly all instances, sidewalks should be provided on both sides of the street, and should be wide enough to accommodate all users without crowding. Sidewalks should be well lit at night, shaded by trees in the summer, and kept clear of snow, leaves, trash and dog waste. Downtown sidewalks should provide amenities such as seating and trashcans.

  On narrow streets with low volumes of traffic (both pedestrian and vehicular), a sidewalk may only be necessary on one side.

• Traffic Calming: The object of traffic calming is to keep traffic below posted speed limits, making it safer for all road users, especially   pedestrians. Unfortunately, most streets built today are wide, with shallow curves and few stops, which encourages speeding. Traffic calming is often applied to these streets retroactively through speed bumps. These are detested by all road users, especially cyclists. The most effective means of traffic calming is to build narrow streets with frequent intersections, where drivers feel most comfortable driving slowly.

• Pedestrian Crossings: Safe crossing points for pedestrians should be provided at all intersections, and at intermediate points on longer blocks. Where there are traffic lights, there should always be a light for pedestrians, which stays lit long enough for an elderly or disabled person to cross.

• Allowance for Transit: Stops for buses and street-running light rail should be integrated with the design of the street, not added as an afterthought. Passengers should not have to step into the roadway or across grass to board. On busier street, bus lanes ease traffic congestion tremendously.