Skip to content

Evaluation of Bicyclist Physiological Response and Visual Attention in Commercial Vehicle Loading Zones

Download PDF  (8.04 MB)
Publication: Journal of Safety Research
Publication Date: 2023

With growing freight operations throughout the world, there is a push for transportation systems to accommodate trucks during loading and unloading operations. Currently, many urban locations do not provide loading and unloading zones, which results in trucks parking in places that obstruct bicyclist’s roadway infrastructure (e.g., bicycle lanes).

To understand the implications of these truck operations, a bicycle simulation experiment was designed to evaluate the impact of commercial vehicle loading and unloading activities on safe and efficient bicycle operations in a shared urban roadway environment. A fully counterbalanced, partially randomized, factorial design was chosen to explore three independent variables: commercial vehicle loading zone (CVLZ) sizes with three levels (i.e., no CVLZ, Min CVLZ, and Max CVLZ), courier position with three levels (i.e., no courier, behind the truck, beside the truck), and with and without loading accessories. Bicyclist’s physiological response and eye tracking were used as performance measures. Data were obtained from 48 participants, resulting in 864 observations in 18 experimental scenarios using linear mixed-effects models (LMM).

Results from the LMMs suggest that loading zone size and courier position had the greatest effect on bicyclist’s physiological responses. Bicyclists had approximately two peaks-per-minute higher when riding in the condition that included no CVLZ and courier on the side compared to the base conditions (i.e., Max CVLZ and no courier). Additionally, when the courier was beside the truck, bicyclist’s eye fixation durations (sec) were one (s) greater than when the courier was located behind the truck, indicating that bicyclists were more alert as they passed by the courier. The presence of accessories had the lowest influence on both bicyclists’ physiological response and eye tracking measures.

Practical Applications
These findings could support better roadway and CVLZ design guidelines, which will allow our urban street system to operate more efficiently, safely, and reliable for all users.

Authors: Dr. Ed McCormackDr. Anne Goodchild, Hisham Jashami, Douglas Cobb, Ivan Sinkus, Yujun Liu, David Hurwitz
Recommended Citation:
Jashami, Hisham, Douglas Cobb, Ivan Sinkus, Yujun Liu, Edward McCormack, Anne Goodchild, and David Hurwitz. “Evaluation of Bicyclist Physiological Response and Visual Attention in Commercial Vehicle Loading Zones.” Journal of Safety Research. Elsevier BV, December 2023.

Ecommerce and Environmental Justice in Metro Seattle

Download PDF  (8.55 MB)
Publication: Research in Transportation Economics
Volume: 103
Publication Date: 2023

Urban distribution centers (UDCs) are opening at unprecedented rates to meet rising home delivery demand. The trend has raised concerns over the equity and environmental justice implications of ecommerce’s negative externalities. However, little research exists connecting UDC location to the concentration of urban freight-derived air pollution among marginalized populations.

Using spatial data of Amazon UDCs in metropolitan Seattle, this study quantifies the socio-spatial distribution of home delivery-related commercial vehicle kilometers traveled (VKT), corresponding air pollution, and explanatory factors. Results reveal that racial and income factors are relevant to criteria air pollutant exposure caused by home deliveries, due to tracts with majority people of color being closer in proximity to UDCs and highways. Tracts with majority people of color face the highest median concentration of delivery vehicle activity and emissions despite ordering less packages than white populations. While both cargo van and heavy-duty truck emissions disproportionately affect people of color, the socio-spatial distribution of truck emissions shows higher sensitivity to fluctuations in utilization.

Prioritizing environmental mitigation of freight activity further up the urban distribution chain in proximity to UDCs, therefore, would have an outsized impact in minimizing disparities in ecommerce’s negative externalities.

Recommended Citation:
Fried, T., Verma, R., & Goodchild, A. (2024). Ecommerce and Environmental Justice in Metro Seattle. Research in Transportation Economics, 103, 101382.

Seattle Microhub Delivery Pilot: Evaluating Emission Impacts and Stakeholder Engagement

Download PDF  (2.87 MB)
Publication: Case Studies on Transport Policy
Publication Date: 2023

Urban freight deliveries using microhubs and e-cargo cycles have been gaining attention in cities suffering from congestion and emissions. E-cargo cycle deliveries and microhubs used as transshipment points in urban cores can replace trucks to make cities more livable. This study describes and empirically evaluates an e-cargo tricycle pilot conducted with multi-sector stakeholders in Seattle to report the potential benefits and pitfalls of such practices. The pilot held stakeholder workshop sessions to collect inputs of interest and expectations from the project. Mobile devices used by drivers on e-cargo tricycle and cargo van routes collected delivery data to use for empirical assessment. Total vehicle miles traveled and tailpipe carbon emissions served as performance metrics when comparing e-cargo tricycle and cargo van deliveries. The results showed the net-benefit of the microhub and e-cargo tricycle routes depend on the upstream operations when replenishing packages.

The participatory approach to pilot design also provided insights into the factors of a successful pilot, with implications for scaling future e-cargo cycle delivery systems in North American cities. Namely, microhubs’ ability to host alternative revenue sources and value-added services is a boon for long-term financial competitiveness. However, lack of digital/physical infrastructure and work training/regulations specific to e-cargo cycle delivery operations present a barrier.

Recommended Citation:
Gunes, Seyma, Travis Fried, and Anne Goodchild. “Seattle Microhub Delivery Pilot: Evaluating Emission Impacts and Stakeholder Engagement.” Case Studies on Transport Policy. Elsevier BV, November 2023.

Intersections and Non-Intersections: A Protocol for Identifying Pedestrian Crash Risk Locations in GIS

Download PDF  (1.35 MB)
Publication: International Journal of Environmental Research and Public Health
Volume: 16 (19)
Pages: 3565
Publication Date: 2019

Intersection and non-intersection locations are commonly used as spatial units of analysis for modeling pedestrian crashes. While both location types have been previously studied, comparing results is difficult given the different data and methods used to identify crash-risk locations. In this study, a systematic and replicable protocol was developed in GIS (Geographic Information System) to create a consistent spatial unit of analysis for use in pedestrian crash modeling. Four publicly accessible datasets were used to identify unique intersection and non-intersection locations: Roadway intersection points, roadway lanes, legal speed limits, and pedestrian crash records. Two algorithms were developed and tested using five search radii (ranging from 20 to 100 m) to assess the protocol reliability. The algorithms, which were designed to identify crash-risk locations at intersection and non-intersection areas detected 87.2% of the pedestrian crash locations (r: 20 m). Agreement rates between algorithm results and the crash data were 94.1% for intersection and 98.0% for non-intersection locations, respectively. The buffer size of 20 m generally showed the highest performance in the analyses. The present protocol offered an efficient and reliable method to create spatial analysis units for pedestrian crash modeling. It provided researchers a cost-effective method to identify unique intersection and non-intersection locations. Additional search radii should be tested in future studies to refine the capture of crash-risk locations.

Authors: Haena Kim, Mingyu Kang, Anne Moudon, Linda Ng Boyle,
Recommended Citation:
Kang, Mingyu, Anne Vernez Moudon, Haena Kim, and Linda Ng Boyle. 2019. Intersections and Non-Intersections: A Protocol for Identifying Pedestrian Crash Risk Locations in GIS. International Journal of Environmental Research and Public Health 16, no. 19: 3565.

Simulation-Based Analysis of Different Curb Space Type Allocations on Curb Performance

Download PDF  (3.49 MB)
Publication: Transportmetrica B: Transport Dynamics
Volume: 11 (1)
Pages: 1384-1405
Publication Date: 2023

Curbspace is a limited resource in urban areas. Delivery, ridehailing and passenger vehicles must compete for spaces at the curb. Cities are increasingly adjusting curb rules and allocating curb spaces for uses other than short-term paid parking, yet they lack the tools or data needed to make informed decisions. In this research, we analyze and quantify the impacts of different curb use allocations on curb performance through simulation. Three metrics are developed to evaluate the performance of the curb, covering productivity and accessibility of passengers and goods, and CO2 emissions. The metrics are calculated for each scenario across a range of input parameters (traffic volume, parking rate, vehicle dwell time, and street design speed) and compared to a baseline scenario. This work can inform policy decisions by providing municipalities tools to analyze various curb management strategies and choose the ones that produce results more in line with their policy goals.

Authors: Thomas MaxnerDr. Andisheh RanjbariŞeyma Güneş, Chase Dowling (Pacific Northwest National Laboratory)
Recommended Citation:
Thomas Maxner, Andisheh Ranjbari, Chase P. Dowling & Şeyma Güneş (2023) Simulation-based analysis of different curb space type allocations on curb performance, Transportmetrica B: Transport Dynamics, 11:1, 1384-1405, DOI: 10.1080/21680566.2023.2212324

Ecommerce and Logistics Sprawl: A Spatial Exploration of Last-Mile Logistics Platforms

Download PDF  (3.64 MB)
Publication: Journal of Transport Geography
Volume: 112
Publication Date: 2023

The rise of ecommerce helped fuel consumer appetite for quick home deliveries. One consequence has been the placing of some logistics facilities in proximity to denser consumer markets. The trend departs from prevailing discussion on “logistics sprawl,” or the proliferation of warehousing into the urban periphery. This study spatially and statistically explores the facility- and region-level dimensions that characterize the centrality of ecommerce logistics platforms. Analyzing 910 operational Amazon logistics platforms in 89 U.S. metropolitan statistical areas (MSAs) between 2013 and 2021, this study estimates temporal changes in distances to relative, population centroids and population-weighted market densities. Results reveal that although some platforms serving last-mile deliveries are located closer to consumers than upstream distribution platforms to better fulfill time demands, centrality varies due to facility operating characteristics, market size, and when the platform opened.

Ecommerce has transformed the “consumption geography” of cities. These transformations have major implications for shopping behaviors and retail channels, last-mile operations and delivery mode choice, the management and pricing of competing uses for street and curb space, and the spatial ordering and functional role of logistics land uses. In the latter case, researchers have observed a diversification of logistics platforms to more efficiently serve home delivery demand. These platforms range from “dark stores” and “microfullfilment centers” that fulfill on-demand deliveries and omni-channeled retail without a consumer facing storefront, multi-use urban distribution centers that convert unproductive sites (e.g., abandoned rail depots) to more lucrative land uses, and “microhubs” that stage transloading between cargo vans and e-bicycles suited for dense urban neighborhoods.

Logistics spaces play an important role in improving urban livability and environmental sustainability. Planning decisions scale geographically from the region-level to the curb. Facilities such as urban consolidation centers and loading zones can mitigate common delivery inefficiencies, such as low delivery densities and “cruising” for parking, respectively. These inefficiencies generate many negative externalities including climate emissions, air and noise pollution, congestion, and heightened collision risks, especially for vulnerable road users such as pedestrians and bicyclists. Limited commercial data has made it difficult, however, to observe spatial patterns with regards to ecommerce logistics platforms.

Using detailed proprietary data, this paper explores the evolving spatial organization of ecommerce logistics platforms. Given the company’s preeminence as the leading online retailer in the U.S., the paper presents Amazon as a case study for understanding warehousing and distribution (W&D) activity in the larger ecommerce space. Utilizing proprietary data on Amazon logistics facilities between 2013 and 2021, this research explores the geographic shape and explanatory dimensions of ecommerce within major U.S. metropolitan areas. In the following section, this study defines the state of research related to broader W&D land use and its implications to ecommerce’s distinct consumption geography. Afterwards, two methodologies for measuring logistics centrality are tested: a temporally relative barycenter-based metric, the prevailing method in literature, and another GIS-based, population-weighted service distance metric. The two measurements reveal nuances between facility- and region-level differences in the spatial organization of ecommerce platforms, which has yet to be fully researched. After presenting results from an exploratory regression analysis, this study discusses implications for future urban logistics land use and transport decisions.

Recommended Citation:
Fried, T., & Goodchild, A. (2023). E-commerce and logistics sprawl: A spatial exploration of last-mile logistics platforms. Journal of Transport Geography, 112, 103692.

Seeking Equity and Justice in Urban Freight: Where to Look?

Download PDF  (2.37 MB)
Publication: Transport Reviews
Publication Date: 2023

What do equity and social justice mean for urban freight planning and management? New Urban Freight Lab paper reviews transportation and mobility justice theory and finds that urban freight issues are absent from these discussions, which primarily concern passenger and personal mobility. When urban freight is considered, authors usually discuss topics such as emissions, pollution, congestion, noise, and collisions. This paper looks more in-depth at urban freight justice, including access to essential goods, community governance, employment opportunities and barriers, and regional and global perspectives.

Urban freight systems embed and reflect spatial inequities in cities and imbalanced power structures within transport decision-making. These concerns are principal domains of “transportation justice” (TJ) and “mobility justice” (MJ) scholarship that have emerged in the past decade. However, little research exists situating urban freight within these prevailing frameworks, which leaves urban freight research on socio-environmental equity and justice ill-defined, especially compared to passenger or personal mobility discussions. Through the lens that derives from TJ and MJ’s critical dialogue, this study synthesizes urban freight literature’s engagement with equity and justice.

Namely, the review evaluates:

  • How do researchers identify equitable distributions of urban freight’s costs and benefits?
  • At what scale do researchers evaluate urban freight inequities?
  • And who does research consider entitled to urban freight equity and how are they involved in urban freight governance?

The findings help inform researchers who seek to reimagine urban freight management strategies within broader equity and justice discourse.

Decades-long growth in urbanization and the more recent surge in e-commerce have spurred concerns around the uneven impacts of freight’s swelling urban footprint. Transport scholars note increasing conflicts between freight vehicles and vulnerable road users, like bicyclists and pedestrians in dense urban areas. Meanwhile, environmental justice (EJ) scholars have long measured unequal exposure to freight traffic pollution along socio-economic and ethnic lines.

However, relatively few urban freight studies engage with social equity. Those that do usually avoid critical discussions contained in justice-oriented theory, instead portraying the movement of goods as an “apolitical science of circulation”. In the U.S., for instance, politicizing urban freight overlooks a history of city industrial zoning practices, infrastructure construction, exclusionary decision-making, and consequent path dependency that placed key logistics facilities including highways, manufacturing plants, warehouses and distribution centers disproportionately near low-income households and non-white, populations of color. The longitudinal effects of these institutional decisions are still largely visible today.

Transportation research also inconsistently defines and measures equity. In a review of equity in transportation literature, Lewis et al. describe equity as an empty conceptual space that “authors then fill … either explicitly with clearly defined arguments or implicitly with whatever idea of justice intuitively comes to mind” (p. 2). Arbitrarily engaging with equity concepts, the authors argue, creates confusion that is both normative (e.g. what does an equitable urban freight system look like?) and positive (e.g. what measurable thresholds determine whether an urban freight outcome is inequitable?). Consequently, most equity research measure unequal distributions of burdens and/or benefits but spend less time identifying when and why unequal distributions are unjust.

Therefore, this paper synthesizes prevailing discourse around equity and, by extension, justice in transportation research and urban freight literature.

Authors: Travis FriedDr. Anne Goodchild, Ivan Sanchez Diaz (Chalmers University), Michael Browne (Gothenburg University)
Recommended Citation:
Travis Fried, Anne Goodchild, Michael Browne & Ivan Sanchez-Diaz (2023). Seeking Equity and Justice in Urban Freight: Where to Look? Transport Reviews, DOI:

An Empirical Analysis of Passenger Vehicle Dwell Time and Curb Management Strategies for Ride-Hailing Pick-Up/Drop-Off Operations

Publication: Transportation
Publication Date: 2023

With the dramatic and recent growth in demand for curbside pick-up and drop-off by ride-hailing services, as well as online shopping and associated deliveries, balancing the needs of roadway users is increasingly critical. Local governments lack tools to evaluate the impacts of curb management strategies that prioritize different users’ needs. The dwell time of passenger vehicles picking up/dropping off (PUDO) passengers, including ride-hailing vehicles, taxis, and other cars, is a vital metric for curb management, but little is understood about the key factors that affect it. This research used a hazard-based duration modeling approach to describe the PUDO dwell times of over 6,000 passenger vehicles conducted in Seattle, Wash. Additionally, a before-after study approach was used to assess the effects of two curb management strategies: adding PUDO zones and geofencing. Results showed that the number of passenger maneuvers, location and time of day, and traffic and operation management factors significantly affected PUDO dwell times. PUDO operations took longer with more passengers, pick-ups (as opposed to drop-offs), vehicle´s trunk access, curbside stops, and in the afternoon. More vehicles at the curb and in adjacent travel lanes were found to be related to shorter PUDO dwell times but with a less practical significance. Ride-hailing vehicles tended to spend less time conducting PUDOs than other passenger vehicles and taxis. Adding PUDO zones, together with geofencing, was found to be related to faster PUDO operations at the curb. Suggestions are made for the future design of curb management strategies to accommodate ride-hailing operations.

Authors: José Luis Machado LeónDr. Anne Goodchild, Don MacKenzie (University of Washington College of Engineering)
Recommended Citation:
Machado-León, J.L., MacKenzie, D. & Goodchild, A. An Empirical Analysis of Passenger Vehicle Dwell Time and Curb Management Strategies for Ride-Hailing Pick-Up/Drop-Off Operations. Transportation (2023).

Estimating Truck Trips with Product Specific Data: A Disruption Case Study in Washington Potatoes

Publication: Transportation Letters: The International Journal of Transportation Research
Volume: 4 (3)
Publication Date: 2013

Currently, knowledge of actual freight flows in the US is insufficient at a level of geographic resolution that permits corridor-level freight transportation analysis and planning. Commodity specific origins, destinations, and routes are typically estimated from four-step models or commodity flow models. At a sub-regional level, both of these families of models are built on important assumptions driven by the limited availability of data. This study was motivated by a desire to determine whether efforts to gather corridor-level freight movement data will bring significant new insights over current approaches to freight transportation modeling. Through a case study of Washington State’s potato and value added potato products industry, we show that significant insight can be gained by collecting commodity-specific truck trip generation and destination data: the approach allows product specific truck trips to be estimated for each roadway link. When considering a network change, the number of affected trips can be identified, and their re-route distance quantified.

Authors: Dr. Anne Goodchild, Derik Andreoli, Eric Jessup
Recommended Citation:
Derik Andreoli, Anne Goodchild & Eric Jessup (2012) Estimating truck trips with product specific data: a disruption case study in Washington potatoes, Transportation Letters, 4:3, 153-166,

SimMobility Freight: An Agent-Based Urban Freight Simulator for Evaluating Logistics Solutions

Publication: Transportation Research Part E: Logistics and Transportation Review
Volume: 141
Publication Date: 2020

Despite significant advances in freight transport modeling in recent years, there is still lack of available tools for evaluating novel logistics solutions. We introduce the framework of SimMobility Freight, which is part of SimMobility, a multi-scale agent-based urban transportation simulation platform. SimMobility Freight is capable of simulating commodity contracts, logistics and vehicle operation planning and parking decisions in a fully-disaggregate manner. This allows us to evaluate alternative logistics solutions and measure their impacts. To illustrate its capability, we conduct an analysis of delivery time window regulations, assessing the policy impacts.

Authors: Dr. Giacomo Dalla Chiara, Takanori Sakai, André Romano Alho, B.K. Bhavathrathan, Raja Gopalakrish, Peiyu Jinge, Tetsuro Hyodo, Lynette Cheah, Moshe Ben-Akivae
Recommended Citation:
Sakai, T., Romano Alho, A., Bhavathrathan, B., Chiara, G. D., Gopalakrishnan, R., Jing, P., Hyodo, T., Cheah, L., & Ben-Akiva, M. (2020). SimMobility Freight: An Agent-Based Urban Freight Simulator for Evaluating Logistics Solutions. Transportation Research Part E: Logistics and Transportation Review, 141, 102017.