A shared street is often referred to as a “pedestrian-priority street,” or, in residential areas, as a “home zone.” Its origins are based in the concept of a "woonerf," which is a Dutch term loosely meaning "street for living." In Seattle and other locations, they are sometimes referred to as "green streets."
It is an integrated space used to better balance the needs of pedestrians, bicyclists, and low-speed motor vehicles. They are usually local-access, narrow streets without curbs and sidewalks, and vehicles are slowed by placing trees, planters, parking areas, and other obstacles in the street. A clear signal is given to designate entrance into the space, either through signage, narrowing of the roadway, and/or different paving materials. Motorists in these areas are encouraged to travel at much slower speeds, approximately 10-15 mph. Rather than relying on traffic controls, street users negotiate right of way in a cooperative manner. The streets often lack signs and markings necessary for the operation of conventional streets, with users instead guided by the physical design of the street. The intended result is that the street and any adjacent commercial businesses are more amenable to bicycle and pedestrian use.
While not technically shared streets, there are also ways streets can be utilized and/or engineered to accommodate a greater variety of street space uses. Many cities are now closing streets during different times of the day or week, such as Winthrop Street in Cambridge, MA, which is closed to vehicle traffic between 11 a.m. and 2 a.m. daily. During the times it is open to vehicles, the street operates as a shared street with vehicle traffic speeds limited to 10 mph. Other cities temporarily close roads on the weekend for local Farmer’s Markets, and cities such as New Orleans, LA, and Memphis, TN, close specific streets nightly. Finally, Portland, OR has created Festival Streets in select areas; one-block streets that function for cars and parking but that do not have curbs, light poles, etc. In doing so, the streets can be converted to public use on weekends or for special events. A film on Festival Streets can be found here.
The speed of motorists on low-volume residential streets and/or in commercial areas makes the use of the street by pedestrians uncomfortable and/or unsafe. Shared streets can improve the safety of pedestrians by removing traditional roadway treatments, encouraging integration, and creating a public space which can be used for social and commercial activities. However, not all streets should be shared by all road users. These should be used only in special situations where all users travel at walking speeds, and there are a nearly equal volume of pedestrians, bicyclists, and motorists.
- Shared streets are generally not appropriate where there is a need to provide nonresident motorists with access to services or through travel.
- As a general rule, streets with greater than 100 vehicles per hour during the afternoon peak should not be considered for shared street treatment.
- The design needs to keep vehicle speeds very low in order to make the streets safe for children.
- The street design must still meet current Americans with Disability Act (ADA) standards, and consideration must be given to provide access by fire trucks, sanitation vehicles and other service vehicles (school buses and street sweepers), where applicable.
- For more information about shared streets, see the white paper Shared Streets and Alleyways, by Alta Planning + Design.
The cost to retrofit a shared street may be quite high, but there would be minimal cost if designed into the original construction.