Skip to content
Technical Report

Managing Increasing Demand for Curb Space in the City of the Future

Download PDF  (3.42 MB)
Publication Date: 2022

The rapid rise of on-demand transportation and e-commerce goods deliveries, as well as increased cycling rates and transit use, are increasing demand for curb space. This demand has resulted in competition among modes, failed goods deliveries, roadway and curbside congestion, and illegal parking. This research increases our understanding of existing curb usage and provides new solutions to officials, planners, and engineers responsible for managing this scarce resource in the future. The research team worked with local agencies to ensure the study’s relevance to their needs and that the results will be broadly applicable for other cities. This research supports the development of innovative curb space designs and ensures that our urban streets may operate more efficiently, safely, and reliably for both goods and people.

The research elements included conducting a thorough scan and documenting previous studies that have examined curb space management, identifying emerging urban policies developed in response to growth, reviewing existing curb management policies and regulations, developing a conceptual curb use policy framework, reviewing existing and emerging technologies that will support flexible curb space management, evaluating curb use policy frameworks by collecting curb utilization data and establishing performance metrics, and simulating curb performance under different policy frameworks.

Recommended Citation:
Chang, K., Goodchild, A., Ranjbari, A., and McCormack, E. (2022). Managing Increasing Demand for Curb Space in the City of the Future. PacTrans Final Project Report.
Technical Report

Understanding Pacific Highway Commercial Vehicle Operations to Support Emissions Reduction Programs

Download PDF  (3.95 MB)
Publication: Transportation Northwest (TransNow)
Publication Date: 2011
This research, enabled by a data collection effort at the international commercial vehicle crossing at Blaine, WA, addressed three key questions regarding commercial vehicle border operations and near border operations. First, what are the unique features of border operations at Blaine, WA, that are not captured within the standard simulation tools (such as Border Wizard)? Second, what logistical inefficiencies are created by the border that increase empty miles traveled, emissions and total travel time between origin and destination? Third, what has the impact of electronic manifest filing been on primary inspection time? The research objectives were to (1) describe near border operations and identify possible solutions to reduce empty truck miles, (2) improve the understanding of the relationship between primary processing time and border crossing time, and (3) identify the impact of ACE (the commercial trade processing system being developed by Customs and Border Protection to facilitate legitimate trade and strengthen border security) electronic manifest filing on primary processing and primary processing time. The report is organized as follows: Chapter 1 describes near border operations through analysis of survey data, current knowledge of the impact of policy on near border facilities, and suggests changes to improve near border operations. Chapter 2 describes the features of processing at Blaine discovered during the data analysis that contribute processing time and border crossing time. Chapter 3 evaluates the impact of ACE on interview time, and compares interview times, crossing times, and volume in the 2009, 2006, and 2001 studies.




Authors: Dr. Anne Goodchild, Matthew Klein
Recommended Citation:
Goodchild, A., & Klein, M. (2011). Understanding Pacific Highway Commercial Vehicle Operations to Support Emissions Reduction Programs (No. TNW2010-11). Transportation Northwest (Organization).
Technical Report

An Examination of the Impact of Commercial Parking Utilization on Cyclist Behavior in Urban Environments

Download PDF  (2.70 MB)
Publication Date: 2016

There is little research on the behavioral interaction between bicycle lanes and commercial vehicle loading zones (CVLZ) in the United States. These interactions are important to understand, to preempt increasing conflicts between truckers and bicyclists. In this study, a bicycling simulator experiment examined bicycle and truck interactions. The experiment was successfully completed by 48 participants. The bicycling simulator collected data regarding a participant’s velocity and lateral position. Three independent variables reflecting common engineering approaches were included in this experiment: pavement marking (L1: white lane markings with no supplemental pavement color, termed white lane markings, L2: white lane markings with solid green pavement applied on the conflict area, termed solid green, and L3: white lane markings with dashed green pavement applied on the conflict area, termed dashed green), signage (L1: No sign and L2: a truck warning sign), and truck maneuver (L1: no truck in CVLZ, L2: truck parked in CVLZ, and L3: truck pulling out of CVLZ).

The results showed that truck presence does have an effect on bicyclist’s performance, and this effect varies based on the engineering and design treatments employed. Of the three independent variables, truck maneuvering had the greatest impact by decreasing mean bicyclist velocity and increasing mean lateral position. It was also observed that when a truck was present in a CVLZ, bicyclists had a lower velocity and lower divergence from right-edge of bike lane on solid green pavement, and a higher divergence from the right-edge of bike lane was observed when a warning sign was present.

Authors: Dr. Anne GoodchildDr. Ed McCormackManali Sheth, David S. Hurwitz, Masoud Ghodrat Abadi
Recommended Citation:
Hurwitz, David S., Ed McCormack, Anne Goodchild, Masoud Ghodrat Abadi, and Manali Sheth. An Examination of the Impact of Commercial Parking Utilization on Cyclist Behavior in Urban Environments. 2018.
Technical Report

Transit Corridor Study

Download PDF  (6.60 MB)
Publication Date: 2021

This study is sponsored by Amazon, Bellevue Transportation department, Challenge Seattle, King County Metro, Seattle Department of Transportation, Sound Transit, and Uber, with support from the Mobility Innovation Center at UW CoMotion.

Population and extended economic growth in many Seattle neighborhoods are driving increased demand for private car travel along with transportation services such as ridehailing and on-demand delivery. Together, these trends are adding to existing demand for loading and unloading operations throughout the city, and exacerbating traffic congestion. Anecdotal evidence indicates that passenger/delivery vehicle stops at or next to transit stops can interfere with bus operations, causing longer or more volatile delays. The increased travel times and reduced reliability further erode the attractiveness of transit to travelers. Thus, it is important to understand how transit, ridehailing, and goods delivery vehicles interact in terms of both operations and travel demand.
This project focuses on the analysis of open-source transit data to screen for locations with slow and/or unreliable bus travel times, and couple that data with interference observation, environmental, and traffic-related data to potentially predict the likely causes. We have developed tools to identify transit corridors with high levels of interference from other road users, including passenger cars, ridehailing vehicles and goods delivery vehicles. These tools are applied to transit corridors in Seattle and Bellevue, and methods have been developed to identify likely sources of interference from available data.
We drew on multiple data sources for identifying high-interference corridors in the region, including:
  • a virtual workshop with participants from beneficiary agencies and stakeholders to solicit input;
  • an online crowdsourcing survey to engage the community and gather feedback from all road users;
  • route-level ridership data from King County Metro; and
  • aggregated pick-up/drop-off data on ridehailing activities from SharedStreets.
Data was consolidated and 10 corridors were selected based on their likelihood of containing interference between buses and other road users, transit ridership levels, and stakeholder and community feedback.
In addition, we have developed a tool for identifying corridors with slow and/or unreliable bus travel times from open-source real-time transit data. We implemented a pipeline for ingesting and analyzing King County Metro’s real-time Generalized Transit Feed Specification data (GTFS-RT) at 10-second intervals. Using this pipeline, active bus coordinate and schedule adherence data has been scraped and stored to an Amazon Web Services (AWS) server since September 2020. We developed efficient methods to aggregate tracked bus locations and assign them to roadway segments, and quantified delays in terms of schedule deviation and ratio of median to free-flow speeds, among other metrics. We have developed a web based visualization tool to display this data, and it is being updated daily with aggregated performance metrics from our database.
To collect ground truth validation data along selected corridors, we implemented an online data collection tool for field observations, and recruited research assistants to observe bus operations along the study corridors and record information on bus traversals and instances of interference. This dataset is analyzed alongside the GTFS-RT data, environmental, and traffic related data to identify instances of delay and predict the likely causes.
Field data was collected for three weeks along eight of the selected corridors in March 2021, but was later paused due to depressed levels of transportation activity during the COVID-19 pandemic and the current unstable condition of travel choices and city traffic (and thus interferences). Preliminary analysis on the collected data revealed that there is not a substantial effect shown in the GTFS-RT data when a bus is interfered with; however, there were not a lot of interference observations in the collected field data. So, it remains to be seen whether the lack of an identifiable effect is due to the lack of ground truth data, lack of precision in the automatic vehicle location system, or the relatively low impact of an interference when compared to the effects of general traffic congestion, signals, and other roadway conditions. A linear regression model was also generated to determine the extent to which roadway characteristics can predict segment performance, which produced mildly predictive results.
As businesses and transit services continue to reopen, there will likely be an increase in the amount of transit interference experienced between buses and other roadway users, which will potentially allow for the gathering of more ground truth validation data. Field observations will resume in late Summer/early Fall 2021 and will continue until enough data is collected to either (1) model connections between observed interference and bus delays in the GTFS-RT data; or (2) determine whether significant delays cannot be linked to observed instances of interference in the study corridors. The GTFS-RT data scraping will continue daily, and summarized in the developed interactive visualization tool.
The major anticipated benefits of the project can be summarized as follows:
  • This work will help identify network-wide road and route segments with slow and/or unreliable bus travel times. We may also be able to identify main causes of delay in the study corridors.
  • Moreover, we expect that this work will generate reusable analytical tools that can be applied by local agencies on an ongoing basis, and by other researchers and transportation agencies in their own jurisdictions.
  • The outcomes of this work will enable identifying corridors with slow and/or unreliable bus travel times as candidates for specific countermeasures to increase transit performance, such as increased enforcement, modified curb use rules, or preferential bus or street use treatments. Targeting such countermeasures towards priority locations will result in faster and more reliable bus operations, and a more efficient transportation network at a lower cost to transit agencies.
Authors: Dr. Andisheh Ranjbari, Zack Aemmer, Borna Arabkhedri, Don MacKenzie
Technical Report

Structural and Geographic Shifts in the Washington Warehousing Industry: Transportation Impacts for the Green River Valley

Download PDF  (2.45 MB)
Publication: Transportation Northwest (TransNow)
Publication Date: 2009
Establishment level employment data indicate that the warehousing industry has experienced rapid growth and restructuring since 1998. This restructuring has resulted in geographic shifts at the national, regional, and local scales. Uneven growth in warehousing establishments across the Pacific Northwest has likely exerted a significant impact on the regional transportation system, but the extent of these transportation impacts remains unknown. Identifying these impacts is the goal of our proposed study. Recent and ongoing research indicates that growth in the warehousing industry is profound. County Business Patterns data published by the US Census Bureau indicates that at the national level, the number of warehousing establishments grew by just over 100 percent from 1998 to 2005. In 1998 there were 6,712 warehousing establishments in the US. By 2005, that number had increased to 13,483. Although a wide range exists within the warehousing industry, interview data collected by the authors of this proposal indicate that each warehouse handles between 25 and 100 trucks, or 50 and 200 trips, hence the location of warehousing establishments has a significant impact on transportation systems. At the county level, we see that in Washington, King County experienced the strongest absolute growth, adding 59 establishments to the 61 reported in 1998. In relative terms, however, Pierce County added warehousing establishments at a faster rate (159 percent) than any other county. The preliminary data produced in Goodchild and Andreoli’s report clearly indicate that there has been strong growth in warehousing establishments at the national and state levels, but that the growth has not been even across states and counties. From a transportation perspective, these findings suggest that future research needs to focus on how these structural and geographic shifts impact regional and local transportation systems.



Authors: Dr. Anne Goodchild, Derek Andrioli
Recommended Citation:
Goodchild, A., & Andrioli, D. (2009). Structural and Geographic Shifts in the Washington Warehousing Industry: Transportation Impacts for the Green River Valley (No. TNW2009-04). Transportation Northwest (Organization).
Technical Report

An Evaluation of Bicycle Safety Impacts of Seattle’s Commercial Vehicle Load Zones

Download PDF  (1.30 MB)
Publication Date: 2015

The Seattle Department of Transportation (SDOT) partnered with the University of Washington to explore how commercial vehicle parking in Seattle’s downtown area affects the safety of bicyclists. The hypothesis was that increased truck access to SDOT’s commercial vehicle loading zones (CVLZs) can positively contribute to bicycle safety. Because CVLZs provide truck drivers with more access to legal parking, their presence could reduce incidences of trucks parking illegally in the street or blocking bicycle lanes, thus reducing the necessity for bicyclists to maneuver around them. This research explored this hypothesis by using four methods, an analysis of bike-trucks accident data, interviews with bicyclists and truck drivers who frequently travel in downtown Seattle, analysis of video recordings of cyclists riding downtown, and observations of truck loading/unloading operations downtown.

The research determined that from bicyclists’ perspectives, illegally parked trucks were a more serious problem than the locations of CVLZs. Therefore, increasing the availability of legal truck parking should have a positive effect on bicyclist safety and level of stress. When trucks park in the bike lane, cyclists are required to maneuver into the stream of traffic, increasing level of exposure and accident risk. Similarly, both the cyclist interviews and video data indicated that construction sites are problematic locations for illegally parked trucks blocking cyclist travel lanes. Better enforcement of parking regulations near construction sites and better site planning would help alleviate a significant amount of conflict between cyclists and parked trucks.

Loading zones on higher speed or busy streets or in areas where cyclists travel downhill increase the danger of those areas. In some areas, it may be possible to relocate loading zones around the corner, onto less busy side streets, to eliminate the need for cyclists to choose between merging into a busy lane to pass a truck or passing close enough to the truck that the delivery operations may put obstacles in the bicyclist’s path. If loading zones are moved, the zones should be situated at the beginning of the block and should allow drivers to still reach the businesses they are serving quickly and without having to maneuver or cross a street. This will encourage the use of the loading zone as opposed to illegal parking.

Recommended Citation:
Butrina, Polina, Edward McCormack, Anne Goodchild, and Jerome Drescher. "An Evaluation of Bicycle Safety Impacts of Seattle’s Commercial Vehicle Load Zones." (2016).
Technical Report

Year Two Progress Report: Technology Integration to Gain Commercial Efficiency for the Urban Goods Delivery System, Meet Future Demand for City Passenger and Delivery Load/Unload Spaces, and Reduce Energy Consumption

Download PDF  (2.46 MB)
Publication: U.S. Department of Energy
Publication Date: 2021

The objectives of this project are to develop and implement a technology solution to support research, development, and demonstration of data processing techniques, models, simulations, a smart phone application, and a visual-confirmation system to:

  1. Reduce delivery vehicle parking seeking behavior by approximately 20% in the pilot test area, by returning current and predicted load/unload space occupancy information to users on a web-based and/or mobile platform, to inform real-time parking decisions
  2. Reduce parcel truck dwell time in pilot test areas in Seattle and Bellevue, Washington, by approximately 30%, thereby increasing productivity of load/unload spaces near common carrier locker systems, and
  3. Improve the transportation network (which includes roads, intersections, warehouses, fulfillment centers, etc.) and commercial firms’ efficiency by increasing curb occupancy rates to roughly 80%, and alley space occupancy rates from 46% to 60% during peak hours, and increasing private loading bay occupancy rates in the afternoon peak times, in the pilot test area.

The project team has designed a 3-year plan to achieve the objectives of this project.

In Year 1, the team developed integrated technologies and finalized the pilot test parameters. This involved finalizing the plan for placing sensory devices and common parcel locker systems on public and private property; issuing the request for proposals; selecting vendors; and gaining approvals necessary to execute the plan. The team also developed techniques to preprocess the data streams from the sensor devices, and began to design the prototype smart phone parking app to display real-time load/unload space availability, as well as the truck load/unload space behavior model.

In Year 2, the team executed the implementation plan:

  • oversaw installation of the in-road sensors, and collecting and processing data,
  • managed installation, marketing and operations of three common locker systems in the pilot test area,
  • tested the prototype smart phone parking app with initial data stream, and
  • developed a truck parking behavior simulation model.
Recommended Citation:
Urban Freight Lab (2021). Year Two Progress Report: Technology Integration to Gain Commercial Efficiency for the Urban Goods Delivery System.
Technical Report

The Final 50 Feet of the Urban Goods Delivery System: Pilot Test of an Innovative Improvement Strategy

Download PDF  (3.07 MB)
Publication: Pacific Northwest Transportation Consortium (PacTrans)
Publication Date: 2019

This report presents a pilot test of a common carrier smart locker system — a promising strategy to reduce truck trip and failed first delivery attempts in urban buildings. The Urban Freight Lab tested this system in the 62-story Seattle Municipal Tower skyscraper in downtown Seattle.

The Urban Freight Lab identified two promising strategies for the pilot test: (1) Locker system: smaller- to medium-sized deliveries can be placed into a locker that was temporarily installed during the pilot test; and (2) Grouped-tenant-floor-drop-off-points for medium-sized items if the locker was too small or full (4-6 floor groups set up by Seattle Department of Transportation and Seattle City Light).

Users picked up their goods at the designated drop-off points. Flyers with information on drop-off-points were given to the carriers. UFL researchers evaluated the ability of the standardized second step pilot test to reduce the number of failed first delivery attempts by (1) Collecting original data to document the number of failed first delivery attempts before and after the pilot test; and (2) Comparing them to the pilot test goals.

Recommended Citation:
Goodchild, A., Kim, H., & Ivanov, B. Final 50 Feet of the Urban Goods Delivery System: Pilot Test of an Innovative Improvement Strategy. (2019)
Technical Report

Safe Truck Parking in PacTrans Interstate Corridors: I-5 and I-90

Download PDF  (1.46 MB)
Publication Date: 2018

Unresolved safety issues caused by truck parking shortages in high-demand locations are of keen importance to the State Departments of Transportation (DOTs) participating in the Regional PacTrans Center and to the thousands of trucking companies and drivers using the Interstate 5 (I-5) and Interstate 90 (I-90) corridors. Safety issues include serious and/or fatal crashes that may be related to the lack of safe and secure parking, and illegal/unofficial parking on entrance and exit ramps, shoulders, and freeway lanes that create hazards for motorists during severe weather.

WSDOT completed a statewide truck parking study in December 2016, and the Oregon Department of Transportation (ODOT) published a report on truck parking along the US97 corridor in July 2017. Both states are interested in addressing safety issues inherent in the current lack of truck parking capacity. Researchers at the Supply Chain Transportation and Logistics Center (SCTL) at the University of Washington developed this project’s research goals with WSDOT to support their work.


The project goals are to:
  • Provide data-based decision support to WSDOT and neighboring states as they develop solutions for the lack of safe truck parking along the I-5 and I-90 corridors.
  • Develop new and valuable insights from truck drivers’ expertise on safety problems resulting from the lack of truck parking capacity on these corridors.
To achieve these goals, the research team first conducted a research scan of existing studies and other online reports that describe the lack of parking in high-demand locations along the I-5 and I-90 corridors in the PacTrans region.

Future Trends 

SCTL identified three trends in the truck parking industry that will affect the truck parking shortage in the future:
  1. The rising cost of land in growing metropolitan areas will continue to intensify this problem. Rapidly increasing land costs create pressure on truck service firms to either create new revenue streams (charging for parking that was formerly included for ‘free’ along with retail fuel sales) or relocate further from metro centers if they cannot compete with higher-value land uses near highway interchanges. Also, manufacturing and wholesale facilities that generate a high number of truck trips will likely continue to maximize building footprints on parcels, reducing available land for on-site truck parking.
  2. Federal regulatory changes are likely to increase long-haul truck parking demand in the next 10 years. In the short term, the electronic logging device (ELD) mandate beginning in 2018 will change driver behavior. Although some long-haul drivers have not strictly followed federal Hours of Service (HOS) regulations in the past, under the new ELD mandate they are more likely to stop and park for required rest periods because it will be more difficult to evade detection. In the next 10 years, additional federal regulations may be enacted and shorten drivers’ HOS again, thereby increasing demand for more rest stops on the Interstate Highway System and other major truck routes.
  3. In the longer term, emerging autonomous and cooperative truck technologies that address driver fatigue are likely to reduce demand for truck stops in rural areas – but not near cities. The truck driver interviews conducted for this project show that drivers stop for business reasons, not just for safety rest periods.

Finally, SCTL conducted 184 interviews of truck drivers over a three-week time period at two high-demand truck stops on the I-5 and I-90 corridors to determine: (a) origin and destination of trips; (b) connection to the Ports of Seattle and Tacoma; (c) drivers’ perceptions of safety issues caused by a lack of truck parking; (d) types of commodities carried; and (e) why drivers parked at these rest stops.

Key Findings 

The SCTL Center’s research provides new data and insights to answer questions under discussion between state, local, and regional transportation agencies and communities in the central Puget Sound region. The research results supported development of the Washington State Freight Mobility Plan. However the project’s findings have not resulted in public funding for additional parking in high-demand locations near I5 and I-90.

One of the most topical questions is whether the state’s economy and/or the Ports of Seattle and Tacoma benefit from the truck trips that require rest stops near the Seattle-Tacoma Bellevue metropolitan area. This question is central to understanding their proportional roles and funding responsibilities to add parking capacity where it is scarce: in the central Puget Sound region.

  • The on-site truck driver survey showed that there is an extremely strong tie between truck parking activity and the state’s economy: 91% percent of trucks parked along I-90 (at TA Seattle East Travel Center in North Bend) and 87% of those parked along I-5 (at the Mustard Seed in Sumner) delivered goods to businesses and other customers within Washington State. The evidence belies the hypothesis that most trucks using parking facilities in Washington are passing through the state and therefore provide no economic value to it.
  • Most drivers using the two truck parking facilities in central Puget Sound were not going to either the Port of Seattle or Port of Tacoma. In fact, 83% of truck drivers parked near I-90 and 78% near I-5 did not go to either of the two container ports. Although port-related traffic uses iv the truck parking facilities, it is not the major cause of increased parking demand at these locations.
  • Why do truck drivers park in these facilities? Surprisingly, more park there – and park longer – for business reasons rather than for safety reasons. The largest group of drivers (34% of those interviewed at TA Seattle East and 36% at Mustard Seed) said their primary reason for the stop was to wait to meet a specific delivery time at their destination or wait to locate another load. When SCTL compared the number of hours parked with the primary reason for parking, it found that delivery operations were the largest driver for longer stays.

The research findings have been used to communicate the importance of providing truck parking in high-demand areas in Washington State, particularly near I-5 south of Seattle and along I-90 near North Bend, to local officials, WSDOT, and other state officials.

By an overwhelming margin, truck drivers who parked along I-5 and I90 near the Seattle-Tacoma-Bellevue metropolitan area delivered goods in Washington State, providing strong evidence that their activities support the state’s economy and residents.

Recommended Citation:
Giron-Valderrama, Gabriela, Barbara Ivanov, and Anne Goodchild. "Safe Truck Parking in PacTrans Interstate Corridors: I-5 and I-90." (2018).
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.