Our alternative design for the “Y” intersection of Santa Cruz & Alameda, and described in our Community Safety Option 10.5, uses a traffic calming and safety design element known as a ‘woonerf’.  In England this design element is commonly called a ‘home zone’. Basically, a woonerf is a shared safety space used for pedestrians, bikes, and residential access. General traffic is prohibited.  Speed limit is usually 5mph. It was first implemented by the Dutch in the 1970s and has spread worldwide since.  The woonerf separates the voluminous through traffic away from other users, leaving a quiet and peaceful ambience.  It separates normal traffic away from residential properties. 

For our Santa Cruz/Alameda safety project, a woonerf would provide the safety design element for changing the “Y” intersection from its roots as an high speed expressway to instead have a much more residential feel, with narrower, calmer, and lower speed roadway. The woonerf has a park like setting and would be adjacent to the northbound Santa Cruz traffic lane on one side and provide a safe park like buffer for residents, pedestrians and cyclists.

This change to a residential style design for the intersection would guarantee a major reduction in traffic speed. Gurarnteed slower speed for NB Santa Cruz traffic through the intersection. Currently the plan calls for keeping a high speed turn, designed for 45-50 mph traffic. While woonerf simplifies the intersection and reduces speed, the same traffic volume would be serviced. In fact, one could argue that more traffic volume could be handled by this design over the County’s expressway based intersection. One reason for this argument is that the County’s design has crosswalks 250% longer than this residential based design alternative. So pedestrians would not require the excessive traffic signal time allocated to cross the road. That in turn results in shorter traffic signal durations and reduced traffic queues on Alameda and Santa Cruz.

Santa Clara County defines a woonerf as ‘a residential street redesigned to be a safe setting for bicycles, pedestrians and even children at play. It typically eliminates curbs and sidewalks thereby creating essentially a linear plaza. Cars are permitted, primarily to access the homes on the street, but they travel at very slow speeds’

Advantages of Woonerf

  • Provides excellent separation of higher speed traffic from residents, cyclists, and people 
  • Creates a calm common community area for greenery, seating, and other esthetic features
  • Changes motorists perception from ‘expressway’ to one of residential/park like ambience
  • Guarantees a 25 mph limit on speed due to an appropriate designed right turn
  • Much safer for cyclists, pedestrians, children, seniors, families, residents
  • Improved access to fire and ER vehicles
  • Trash collection, USPS and other delivery vehicles, street sweepers don’t block main traffic flow
  • Significantly reduces the intersection size – from a massively wide and angled intersection

For an example of how a woonerf can be used in one of the most dangerous intersections in San Mateo County, see the community information for the Santa Cruz/Alameda intersection in West Menlo Park where the community has a design known as Safety Option 10.5.

References and Additional Information

BoundaryCompanies.com, What’s a Woonerf?  The Streetscape design that’s sweeping DC

Humankind.city, The 4 Principles of a Woonerf

Livable Streets:  Protected Neighborhoods?, Donald Appleyard

Santa Clara County Transportation Authority, Bicycle & Pedestrian Advisory Committee

Authored Jan 2023, Safety@Safer4Us.com

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