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Freight and Transit Lane Study (Task Order 7)

The City of Seattle Department of Transportation (SDOT) engaged the Urban Freight Lab to conduct research on the impacts of a Freight and Transit-Only (FAT) Lane in place in January 2019. The research findings will be used to understand the FAT Lane’s performance towards achieving city goals and to guide the development of future FAT Lane projects.

The Seattle Freight Master Plan includes a FAT Lane strategy to reach the city’s economic goals:

  • (2) Economy – Provide a freight network that supports a thriving and diverse economy for Seattle and the region.
  • (2.4) Maintain and improve truck freight mobility and access between and within the city’s MICs and to the regional highway system
  • (2.4.2) Explore and test the use of truck-only lanes to improve freight mobility on city streets with high truck volumes

SDOT’s key research interests in this project are to:

  1. Document whether the FAT Lane’s benefits to truck drivers were strong enough to attract heavy freight vehicles from using other downtown streets. This will be measured by comparing truck volume on the Lane during implementation to volume after it was closed.
  2. Determine whether passenger cars followed the posted FAT Lane restrictions. This will be measured by documenting the number of cars violating the rule.
  3. Document transit use during the implementation period.


The Alaskan Way Viaduct, a major freight thoroughfare in Seattle, was closed on January 11, 2019 significantly reducing capacity in the already congested road network in Greater Downtown Seattle. To improve freight and transit access to commercial and industrial areas in the city, the City of Seattle Department of Transportation, in partnership with the WSDOT, temporarily installed two blocks of a Freight and Transit Lane on Alaskan Way.

The FAT Lane was in the curb lane only, on southbound Alaskan Way (at street level, not on the Viaduct). The 2-block segment is north of Little H on Alaskan Way, which provides access to Colorado and Alaskan Way. The FAT Lane supported Port of Seattle operations.

Research Tasks:

The following tasks will be completed by the Urban Freight Lab:

Task 1 – Research Scan


  1. Conduct a short research scan of published reports that provide data-based evidence of the results of FAT Lane projects.
  2. Write a 2-3 page summary of the results of other FAT Lane projects

Task 2 – Analysis of video data


  1. SDOT will provide video of the FAT Lane segment taken when the Lane was open and after it closed, to the UFL. The UFL will categorize and count vehicles in the lane as follows:
    • Transit/bus
    • Passenger/car
    • Truck/freight:
      1. Drayage with container
      2. Drayage without container
      3. All other trucks/freight vehicles. This category includes: delivery vans/trucks, construction and waste vehicles, and if readily apparent service commercial vehicles.
    • Other vehicles, e.g. those lacking differentiating features to categorize.
  2. UFL will analyze the count data and include key findings in the final report. The analysis will include:
    1. A comparison of truck volume on the Lane during implementation to the volume after it was closed. This may include time of day, day of week, or other factors.
    2. The number of passenger cars in the Lane during implementation. e.g. the number of violators.
    3. The UFL researchers will also explore whether comparing data collected in the Greater Downtown Cordon study to data collected in this study yields valid findings.

Ballard Cordon Data Collection for Trucks and Cars (Task Order 8)

The Ballard Cordon Data Collection for Trucks and Cars is an analysis research project to be conducted by the Urban Freight Lab for the City of Seattle Department of Transportation (SDOT). Truck and car counts will be collected by reviewing video data for Major Truck Streets using the same Federal Highway Administration (FHWA) vehicle classification and additional large classifications as was developed and performed in the Greater Downtown Seattle Area Cordon Data Collection for Trucks and Cars project. This will enable SDOT to consider the impacts of various economic growth scenarios, advanced freight vehicle technologies, and other drivers (social, demographic, and policy changes) on truck routes.

Task 1 – Kickoff Meeting
SCTL will hold a kick-off meeting to:

  1. Identify count locations from which 48-hour and 72-hour data will be gathered and processed throughout the City.
  2. Identify prioritized count locations generally in the Ballard neighborhood and Ballard Interbay North Manufacturing and Industrial Center (BINMIC) for which a preliminary analysis will be provided.

Task 2 – Corridor Data Analysis
SCTL will review collected truck and car counts from video data recorded:

  1. SCTL will provide analysis regarding directionality, type, and any trends observed in the transcribed video based on developed typology of truck and van vehicle types for the video count data provided.
  2. The analysis will be divided into three categories:
    • A review of all cordon counts, including cordon counts around the downtown core
    • A review of Major Truck Street corridors on which counts were taken
    • A review of counts related to the BINMIC​

Task 3 – Reporting
The Urban Freight Lab will produce a written report documenting the methodology used and explaining the data collection, with simple descriptive statistics.

Technical Report

Characterization of Seattle’s Commercial Traffic Patterns: A Greater Downtown Area and Ballard/Interbay Vehicle Count and Evaluation

Download PDF  (5.59 MB)
Publication Date: 2021

Seattle now ranks as the nation’s sixth-fastest growing city and is among the nation’s densest. As the city grows, so do truck volumes — volumes tied to economic growth for Seattle and the region as a whole. But many streets are already at capacity during peak hours and bottleneck conditions are worsening. This project is designed to deliver critical granular baseline data on commercial vehicle movement in two key areas of the city to help the city effectively and efficiently plan for growing freight demand.

This timely research from the Urban Freight Lab (UFL) on behalf of the Seattle Department of Transportation produces Seattle’s first complete estimate of Greater Downtown area traffic volumes. And it offers a detailed analysis of commercial vehicle traffic in and around one of the city’s two major industrial centers, the Ballard-Interbay Northern Manufacturing Industrial Center.

These efforts are significant because the city has lacked a comprehensive estimate of commercial vehicle volumes until now. In the Greater Downtown area, the cordon counts (tracking traffic in and out of 39 entry/exit points) alongside traffic volume estimates will provide a powerful tool for local government to model, evaluate, develop, and refine transportation planning policies. This study lays the groundwork for the first commercial vehicle traffic model that will enable the evaluation of different freight planning and traffic management strategies, economic growth scenarios, and application of new freight vehicle technologies. Ballard-Interbay is slated for major infrastructure projects in the coming years, including new Sound Transit stations and critical bridge replacements. This analysis will help inform these projects, which are critical to an efficient, reliable transportation system for goods and people.

One overall finding merits attention as it suggests the need to update some of the freight network element categories defined in the current Seattle Freight Master Plan. The SCTL research team finds that the volume of smaller commercial vehicles (such as pick-ups, vans, and step vans) is significant in both the Greater Downtown area and Ballard-Interbay, representing more than half of all commercial vehicles observed (54% in the Greater Downtown area and 60% in Ballard-Interbay.) Among those smaller commercial vehicles, it is service vehicles that constitute a significant share of commercial traffic (representing 30% in the Greater Downtown area and 40% in Ballard-Interbay.) Among the myriad possible ramifications of this finding is parking planning. An earlier SCTL research paper (1) found service vehicles tend to have longer dwell times, with 44% of all observed service vehicles parked for more than 30 minutes and 27% parked for an hour or more. Given this study’s finding of service vehicles representing a significant share of commercial traffic volume, these vehicles may have a disproportionate impact on parking space rates at the curb.

Comprehensive planning requires comprehensive data. Yet cities like Seattle often lack the detailed data needed for effective freight planning, from peak hours and fleet composition to activity type and gateways of entry/exit. And if cities do have data, they are often too highly aggregated to be useful for management or planning or suffer from lack of comparability or data confidentiality problems.

Currently, urban traffic volume estimates by Puget Sound agencies are limited in spatial and vehicular detail. For example:

  • Seattle Department of Transportation (SDOT) is responsible for recording traffic counts through the year on selected arterial streets in Seattle, providing a seasonally adjusted average weekday total vehicle traffic for all lanes at all count locations.
  • Washington Department of Transportation (WSDOT) provides annual average daily traffic volumes in select locations of their jurisdiction, including the major interstates and state highways in the Seattle area. This data includes truck volume separated into three types: single, double, and triple units.
  • Puget Sound Regional Council (PSRC) regional truck model has three levels of vehicle classification: light commercial, medium trucks, and heavy trucks. This is based on WSDOT Annual Traffic Flow’s count locations and additional manual counts for model validation through the Puget Sound Region.

But none of these existing efforts produce enough detail to understand Seattle’s vehicle movements or connect them with economic activity. To fill the gap, Seattle could consider adopting a standard freight-data reporting system that would emphasize collecting and distributing richer and better data for time-series analysis and other freight forecasting, similar to systems used in cities like Toronto and London. Seattle is a national leader when it comes to freight master plans. This study offers a critical snapshot of the detailed data needed for effective policy and planning, potentially informing everything from road maintenance and traffic signals to electric vehicle charging station sites and possible proposals for congestion pricing. That said, Seattle could benefit greatly from sustained, ongoing detailed data reporting.

Recommended Citation:
Urban Freight Lab (2021). Characterization of Seattle's Commercial Traffic Patterns: A Greater Downtown Area and Ballard/Interbay Vehicle Count and Evaluation.