Transit Lanes

Updated: 8/4/2022


Transit lanes help keep transit moving by separating transit from other vehicles. They reduce transit travel times and make transit travel times more reliable, especially when traffic is heavy, by minimizing congestion-related delays. Our goal is to make transit a preferred transportation choice for all people traveling in Seattle. One way we are working toward this goal is by expanding our network of transit lanes, including bus-only lanes, to create a more reliable and effective transit system. You can learn more about the other ways we are improving transit on our Transit Program webpage

Facts about bus-only lanes: 

  • People driving cars and trucks cannot travel in lanes marked and signed as “bus-only”. Lanes painted red are restricted to buses only 24 hours a day and 7 days a week.
  • People driving can enter bus-only lanes to make right turns into driveways and at intersections
  • People biking can use bus-only lanes
  • Emergency response vehicles can use bus-only lanes when responding to an incident
  • Only public transportation vehicles can use marked “bus-only” lanes. This does not include school buses, vanpools, work shuttles, motorcycles, carpools or charter buses.  

Benefits of the transit lane network

Expanding our network of transit lanes helps people riding transit get to where they're going quicker and more reliably. Improvements to the transit system also benefit everyone. Transit can better serve more people if travel times are consistent and reliable. When transit better serves people, we can reduce car trips, reduce congestion on our streets, and help more people get to where they need to go on time. 

Transit lanes help buses more move efficiently, saving time for bus riders

Dedicated bus-only lanes help buses avoid becoming stuck in traffic congestion and more likely to be on-time and/or complete a trip in less time. Every minute saved can benefit hundreds or thousands of people riding transit each day. These time savings mean people spend less time waiting for the bus, less time on the bus, and have more certainty about how long their trip will take. As bus travel times improve and become more consistent, bus schedules can be adjusted to reflect faster trips. In some cases, more bus service can be added with the time saved.

Shifting more trips to transit helps improve the efficiency of our road space, benefiting everyone 

Transit lanes make transit trips more reliable and consistent. Consistent and reliable travel times can make transit a better transportation option for more people. As more people shift more trips to transit, we can better manage congestion our streets. Less congestion means that it is easier for people using other modes to get around. When we use our streets more efficiently, more people spend less time stuck in congestion.  

As Seattle continues to grow and we continue work toward our bold climate vision, it will become even more important to use limited road space more efficiently and equitably. Transit can move more people per hour compared to other modes of transportation. 

Transit can move more people per hour compared to other modes. As more people shift more trips to transit, we can help reduce congestion on our streets for people who need to travel by modes such as cars for certain trips. Graphic developed by National Association of City Transportation Officials.

Graphic developed by National Association of City Transportation Officials. Click here to see an enlarged image

Investments today will help build a more equitable, sustainable, and efficient transportation system 

Many people rely on transit each day to get where they need to go and meet their basic needs. This remained true during the COVID-19 pandemic when transit ridership remained high on many routes. In particular, transit ridership stayed high in neighborhoods with more people of color. We know that convenient and reliable transit service is needed in these communities as we recover from the pandemic. We're making transit investments in these areas now to align with our core values around transportation equity.

The map below shows the bus routes with the top 10 highest ridership in 2020, and the percentage of Black, Indigenous and People of Color by census tract. We use data such as this, and our Racial and Social Equity Index, to help identify priority areas for transit lanes and transit investments.   

King County Metro Routes in Seattle with Highest Daily Ridership During COVID and Percent People of Color by Census Tract.

Click here to see an enlarged map

For people riding transit, reliability can be especially important. A late trip could mean a missed transfer to another route or being late to an appointment or job. In some cases, people may choose to drive because they know how long a car trip usually takes. Relying on cars can have dramatic financial and environmental impacts. A person can save an average of nearly $10,000 a year when they switch from driving a car to taking transit for their daily commute (American Public Transportation Association's (APTA) June Transit Savings Report). 

Providing high-quality transithelps everyone have access to reliable and affordable transportation options.

Prioritizing transit helps achieve other City priorities

Building a more efficient, reliable, and equitable transit system contributes toward other priority plans and initiatives across the City of Seattle, including the Climate Action Plan, Comprehensive Plan, and Transportation Equity Program. To meet the goals identified in these plans, transit must be a safe, convenient, and reliable transportation option for all people. 

The transportation sector is the largest source of greenhouse gas emissions in Seattle. By 2030, the City's goal is to reduce passenger vehicle emissions by 82 percent from the 2008 levels. Based on data through 2018, Seattle has reduced passenger vehicle emissions by only 3 percent. To achieve the 2030 goals, we need to take significant action, including shifting more trips from personal vehicles to low- or zero-emissions transit.  

In 2018, transportation made up 60 percent of Seattle's greenhouse gas emissions (2018 Seattle Climate Action Plan). Seattle's Office of Sustainability and Environment has more information about our efforts to address the climate crisis, including priority transportation initiatives, and information about how we measure greenhouse gas emissions in Seattle

2018 Seattle Greenhouse Gas Emissions by Sector

2018 Seattle Greenhouse Gas Emissions by Sector

(Source: 2018 Community Greenhouse Gas Emissions Report). Click here to see an enlarged image

Improving our approach to where we put transit lanes 

We are updating our internal policy that guides decisions about where to install bus lanes and how to evaluate them. Currently, most transit lanes in Seattle are implemented on a project-by-project basis. Our new internal policy will create a more transparent and consistent process to how we select, build, and evaluate transit lane projects. Other SDOT programs also will be able to use this policy to incorporate transit lanes into planned projects. See below for more information on current transit lane projects.

Centering equity

To ensure that the updated policy centers equity, we are hosted a focus group with a small group of people who applied for the original Transportation Equity Workgroup. In these focus groups we shared our work to develop an updated policy. Feedback received in these focus groups helped inform the policy development. We held these focus groups in early 2022. We will share more information on this webpage about what we heard and how that feedback informed our policy recommendations.   

Developing a Transit Lane Policy 

Our work to update our internal policy builds on the work done through the Modal Integration Policy Framework. The framework provides high-level guidance on where and when to prioritize transit on city streets. The new policy also responds to feedback received from the Transportation Equity Workgroup. This group recommended we increase transparency about where and why we build bus lanes. We are worked closely with King County Metro and incorporated feedback from Seattle's Modal Advisory Boards (Bike, Pedestrian, Freight, and Transit) to inform the new policy.

By early 2022, we will have an updated draft transit lane policy and initial recommendations for near-term transit lane projects. These recommendations will inform the Seattle transportation plan - a new 20-year plan that tells the story of Seattle's shared transportation and public space vision with steps to achieve it. More information on the Seattle transportation plan, including public engagement opportunities, will be shared by early next year. 

How have we identified bus lane opportunities in the past?

We begin by evaluating routes on the Frequent Transit Network to identify possible transit lane projects. We apply a set of metrics and criteria to understand where the transit lanes could further improve speed and reliability of transit trips.

Examples of these metrics and criteria include:

  • Demographics and areas of need
  • Passenger trips and passenger loads (or passenger demand)
  • Passenger delay
  • Travel time variability and reliability

Our updated policy includes additional equity-focused criteria. This criteria will allow us to identify priority locations for transit lanes that can contribute toward building a more equitable transit system.

The updated policy will also:

  • Clarify how transit lane projects are selected and prioritized  
  • Identify transit lane performance standards
  • Provide a clear process to evaluate the effectiveness of transit lanes
  • Provide a clear process to determine if or when changes should be made to improve the performance of transit lanes

We will continue to share more information as the draft policy is further developed. 

Transit lanes in Seattle

Transit lanes are travel lanes in the street that can only be used by transit, such as buses and streetcar. Some transit lanes can only be used by transit 24 hours a day, while other transit lanes are only restricted to transit during specific times of the day or days of the week. Signs and markings on the street indicate if/when transit lanes can be used by other vehicles, including for parking. Most transit-only lanes allow people driving other vehicles to enter the lane to make right turns at intersections or to turn into driveways.

There are 3 main types of transit lanes in Seattle:

These lanes only allow buses during specific times of the day (usually "peak" times, or times of the day when traffic is heaviest). They are often called "business access and transit (BAT) lanes", which are curbside lanes restricted to buses but also allow people driving to make right turns or access driveways. People biking are allowed to use curbside transit lanes too. 

An example of a time restricted bus-only lane.

These transit lanes can only be used by buses 24 hours a day, 7 days a week. These lanes are usually painted red to help people driving more clearly see that the lanes are restricted to buses. Like BAT lanes, some all-day bus lanes allow people driving to make right hand turns at intersections. People on bikes are also allowed to use curbside all-day bus-only lanes. 

An example of all-day bus-only lanes.

These are major pathways or series of streets where transit is given the priority over other vehicles. Different types of transit use these corridors, including buses, light rail, and streetcars. Restrictions vary, including times of day that only transit is allowed and if/when other vehicles allowed. These restrictions are signed and/or marked. There are several existing dedicated transit corridors in Seattle, including:

  • 3rd Ave in downtown
  • SODO busway, which runs on 5th Ave S from S Spokane St to S Royal Brougham Way
  • Northbound 5th Ave from S Washington St to Marion St in downtown
  • Southbound 14th Ave in First Hill (used by the streetcar) from E Yesler Way to S Jackson St

An example of dedicated transit corridors.

These include:

  • Transit/High Occupancy Vehicle (HOV): Transit/HOV lanes provide a dedicated lane for transit and vehicles with two or more people. In Seattle, these are often found on highway on-ramps or on highways themselves, such as I-5 through downtown Seattle. 
  • Freight and Bus Lanes (FAB): FAB lanes are "Bus Only" lanes that have markings and signs allowing freight trucks. They can also be "Freight Only" lanes with markings and signage also allowing buses. There are not any FAB lanes currently installed in Seattle, but we are considering the role they could play in the future. 

Did you know? People biking can use transit lanes too!

Current Transit Lane Projects

We are making low-cost improvements to enhance safety and convenience on our streets and improve transit reliability. Some recent projects completed by the Transit Spot Improvement Program include bus-only lanes 15th Ave NE between NE 45th St & NE 40th St and on 3rd Ave between Stewart St and Virginia St. 

Transit spot improvement on 3rd Ave in downtown Seattle

Transit spot improvement on 3rd Ave in downtown Seattle

Projects such as this help reduce travel delay for transit riders. Read more about these spot improvement projects

The Transit-Plus Multimodal Corridor program is another priority initiative to implement transit lanes along priority transit corridors as well as incorporating a variety of other transit and multimodal improvements. For more information on these projects, visit the Transit-Plus Multimodal Corridor webpage

SDOT and King County Metro are partnering on improvements to make transit service more frequent, reliable and high-quality on three RapidRide corridors. On these projects, we'll also deliver multimodal improvements like repaved roads, pedestrian access, and safety improvements, bicycle facilities, signal improvements, and other street or utility upgrades. SDOT and King County Metro are currently working to make RapidRide investments to these three corridors:

For the RapidRide G and RapidRide J Line, the level of investment is contingent upon securing Federal Transit Administration (FTA) Small Starts funding and other grant funding. We've been working with the FTA to secure these funds. Read about King County Metro RapidRide.

As we continue to rebuild and recover from the COVID-19 pandemic, we are working toward building a just and equitable transportation network that will help people move and thrive. We are working to identify priority areas for transit lane projects in 2022. These priority areas are corridors where transit ridership remained high throughout the pandemic, and where our analysis shows that the addition of a transit lane could improve the speed and reliability of buses. Investments in these areas will help serve people who relied on transit the most during the pandemic and who will likely continue to rely on transit as we move forward. The addition and expansion of transit lanes on these corridors and investments in transit for these communities will help build a more just and equitable transit network. We will share more information about these priority projects and begin outreach in early 2022.


Thank you, Seattle! Many of our current transit lane projects are possible thanks to 80 percent of Seattle voters passing the Seattle Transit Measure (Proposition 1) in November 2020, which created a revenue source for more frequent, reliable, accessible bus service in our city. Through a 0.15% sales tax (the equivalent of 15 cents on a $100 purchase) you are directly supporting access to transit in your communities. 

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Greg Spotts, Director
Address: 700 5th Ave, Suite 3800, Seattle, WA, 98104
Mailing Address: PO Box 34996, Seattle, WA, 98124-4996
Phone: (206) 684-7623

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The Seattle Department of Transportation (SDOT) is on a mission to deliver a transportation system that provides safe and affordable access to places and opportunities for everyone as we work to achieve our vision of Seattle as a thriving, equitable community powered by dependable transportation.