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New Research: A Data Visualization of Traffic in and Out of Downtown Seattle

New Research: A Data Visualization of Traffic in and Out of Downtown Seattle
New Research: A Data Visualization of Traffic in and Out of Downtown Seattle
August 11, 2019   //   

AUGUST 11, 2019 Seattle is the fastest-growing city in the United States. Since 2010, the population in Seattle has grown nearly 20%. What role do vehicles play in this growth?  As the city grows, how might transit and freight systems meet the demands of both residents and businesses?

The Urban Freight Lab concluded a Truck/Passenger Vehicle Cordon Count project this month, a detailed count and analysis of all vehicles moving into and out of Seattle’s city center, in order to provide the Seattle Department of Transportation with baseline information about commercial movement and guide an update of the city’s freight master plan. Seattle is now the first city to develop a database that provides such detailed vehicle use information.

“We know traffic is heavy; we know it’s busy,” Chris Eaves, SDOT Engineer said. “But this is the first time we know of anywhere where we’re evaluating those trucks’ use, so we can understand what is coming in and take the first steps to correlate why.”

Video capturing all traffic entering and leaving downtown on 15 major and minor truck routes was taken last October at 48-hour and seven-day intervals. Researchers counted vehicles, developed a typology, and provided a detailed analysis of vehicle type, such as delivery trucks, construction vehicles, service vans, and waste management vehicles.

A new detailed visualization shows the vehicle distribution, patterns in overall traffic counts, and inflection points throughout the day.

Key findings include:

  • Traffic flow at the 4th Ave. S. and S. Holgate Street intersection consists of:
    • Service vehicles: 18.8%
    • Waste management vehicles: 8.8%
    • Freight is the largest user, with 32.1% of the commercial total
    • Goods delivery vehicles: 33.5%
    • Construction vehicles: 12.8%
    • General small fleet vehicles: 25.7%
  • Commercial vehicles account for 13.8% of all volume on the network
  • Commercial vehicles reach peak counts at 9:45 a.m.
  • Vehicles exiting surpass vehicles entering at 2 p.m.
  • Vehicles entering surpass vehicles exiting at 4 p.m.


About the Urban Freight Lab (UFL): An innovative public-private partnership housed at the Supply Chain Transportation & Logistics Center at the University of Washington, the Urban Freight Lab is a structured workgroup that brings together private industry with City transportation officials to design and test solutions around urban freight management.

About the Supply Chain Transportation & Logistics Center: The Supply Chain Transportation and Logistics Center at the University of Washington is the go-to place to analyze and solve urban goods delivery, sustainability, logistic hubs and ports, and freight system performance management problems that overlay private and public spaces and control. Our work integrates in-depth consultation with industry and the public sector, transformative research, and executive education, and serves the powerful nexus of industry, transportation infrastructure, and policymakers.

In the Media:

Freight Waves: First-of-its-kind study to analyze truck traffic in Seattle downtown core