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2017 Seattle Traffic Report

Between 2015 and 2016 Seattle’s population increased by 2.9% – from 684,451 to 704,352 people. That means we added nearly 20,000 new neighbors, making Seattle the fastest growing city in the U.S. The annual 2017 Seattle Traffic Report is a review of our core data sets including traffic volumes, speeds, and reported collisions that help our traffic engineers and planners evaluate changes and improvements to city streets.


2017 Seattle Traffic Report Highlights: 

Based on 2016 traffic data and in the midst of rapid growth, we found that:


We’re making progress towards our Vision Zero goal to end traffic deaths and serious injuries on city streets by 2030.

Recent Vision Zero safety corridor projects on 35th Ave SW, SW Roxbury St, and Rainier Ave have successfully eliminated fatal and serious injury crashes from the project limits and reduced all crashes by 2.6%.


We’re successfully moving more people via transit and other options instead of driving.

Transit ridership increased by 4.8%, the highest increase in the nation. Commute Seattle’s Mode Split Survey that found that 95% of new commute trips into downtown Seattle are being accommodated by transit and other modes versus driving alone.


Adding more permanent bike counters to better track ridership year-round will help us collect more data on annual ridership numbers.

Bicycle volume measurements in Seattle are moving towards the same methodology as vehicle measurements.


Managing Growth

Traffic volumes in Seattle remain unchanged from 2015 to 2016. This is the opposite of what’s happening in the region and U.S.:

  • In King County’s urban roadways, WSDOT reports vehicle miles traveled in 2016 increased by 2%.
  • Statewide, traffic volumes increased by 2.9% (58 to 59.7 billion miles traveled).
  • Across the U.S., traffic volumes increased by 3.2% (3.1 to 3.2 trillion miles driven on U.S. roads).



Fatalities declined by approximately 5% from 21 in 2015 to 20 in 2016, which is much better than the national and Washington state trends.

  • National fatalities increased 5.6% from 35,485 to 37,461.
  • Washington state fatalities increased 19.3% from 462 to 551.

Pedestrian safety

Seattle’s pedestrian fatalities decreased from 7 to 5. Nationally, pedestrian fatalities increased by 9%, its highest since in 1990.

Bicyclist safety

Seattle experienced 3 bicycle fatal collisions, up from 1 fatal collision in 2015. Serious bicycle injury and fatal collisions increased by 16.5% from 26 to 29. Bicycle fatality increased 1.3% nationally and is at its highest since 1991. The 2nd Avenue protected bike lanes (PBL) experienced one non-injury collision in 2016.


Serious injuries for all crashes increased by 19.6% from 143 to 171.


The Traffic Report summarizes crash data and traffic statistics, so we can track trends from year to year, but behind each one of these data points is a person. That’s why our Vision Zero goal is so important – because one fatality is too many.


Bike Data

Bicycle ridership declined by 2.6% partly due to our extremely wet weather from October through December when Seattle had 27 days of rain in October, 24 days in November, and 22 rain days, and 8 snow days in December. In addition, an evolving transportation system: Light rail opening at Husky Stadium likely shifted bicycle trips to that area instead over one of our permanent bicycle counters. Free floating bike share was not included in 2016 data.


See the full 2017 Seattle Traffic Report.