Reducing Single-Occupant Vehicle Trips - What & Why

What's Happening Now?

The City Council is considering Land Use Code amendments that will implement new "level-of-service" standards for the City's transportation network. Level-of-service standards help us measure traffic congestion within Seattle. The new standards were adopted by the City in the 2016 major update to the Comprehensive Plan. 

Previously, level-of-service standards compared the volume of automobiles using city streets during peak commuting hours to the capacity of those same streets.

The new level-of-service standard is the percentage of trips made by single occupancy vehicles (SOV) within different sectors of the city.  Periodic travel surveys by the Puget Sound Regional Council will let us know how we are doing.

The new level-of-service standards are consistent with Comprehensive Plan goals to encourage different personal transportation choices such as taking transit, bicycling, and walking more often. The standards make the best use of our limited available street capacity, increase the ability of our streets to move more people efficiently, and reduce reliance on single occupancy vehicles (see linked graphic - street efficiencies gained).

The proposed Code amendments help ensure that new development projects above a certain size contribute fewer single occupancy vehicle trips using the City's roads. The requirement would apply to:

  • Residential uses with more than 30 dwelling units or sleeping rooms
  • Non-residential uses greater than 4,000 square feet of gross floor area
  • Non-residential uses in Industrial zones that have more than 30,000 square feet of gross floor area used for agricultural purposes, high impact uses, manufacturing, storage, transportation facilities, or utilities  

Projects located within Urban Centers, Hub Urban Villages, and light rail station areas already meet these requirements because transportation choices made in these areas are quite efficient and support the City's transportation planning goals. Outside of these areas, new development must take steps upfront to promote more efficient travel choices, such as:

  • Subsidizing transit passes
  • Providing nearby sidewalk and curb cut improvements
  • Reducing the amount of parking provided in new buildings
  • Including a mix of uses in their development  

The proposal includes a preliminary draft joint SDOT and SDCI Directors' Rule that establishes the choices new developers and building owners will have.

Project Benefits

The coming of more light-rail service in North Seattle in a few years will help boost the convenience and effectiveness of these transportation choices.  This should make a difference in how many vehicles are using our streets during peak hours.

We are asking developers to make choices about project location, design, and amenities that will make it easier to use and access transit and other alternatives to driving alone. 

The End Result

Our transportation system will benefit by moving more people with more efficient travel options to make better use of its overall capacity.  For those traveling on our streets, this will help avoid traffic gridlock, and ensure the system provides people with good options for moving around the city.

People will be able to move more safely in their neighborhoods with street, sidewalk, and bicycling system improvements.

People will be able to make efficient travel choices that save them money; the costs of driving and maintaining a vehicle are more expensive than other transportation options.