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Paper

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

 
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Publication: Journal of Safety Research
Publication Date: 2023
Summary:

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).

Method
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
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. https://doi.org/10.1016/j.jsr.2023.11.018
Paper

Ecommerce and Environmental Justice in Metro Seattle

 
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Publication: Research in Transportation Economics
Volume: 103
Publication Date: 2023
Summary:

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. https://doi.org/10.1016/j.retrec.2023.101382
Paper

Seattle Microhub Delivery Pilot: Evaluating Emission Impacts and Stakeholder Engagement

 
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Publication: Case Studies on Transport Policy
Publication Date: 2023
Summary:

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. https://doi.org/10.1016/j.cstp.2023.101119.
Paper

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

 
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Publication: International Journal of Environmental Research and Public Health
Volume: 16 (19)
Pages: 3565
Publication Date: 2019
Summary:

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. https://doi.org/10.3390/ijerph16193565
Paper

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

 
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Publication: Transportmetrica B: Transport Dynamics
Volume: 11 (1)
Pages: 1384-1405
Publication Date: 2023
Summary:

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
Paper

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

 
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Publication: Journal of Transport Geography
Volume: 112
Publication Date: 2023
Summary:

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. https://doi.org/10.1016/j.jtrangeo.2023.103692
Paper

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

 
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Publication: Transport Reviews
Publication Date: 2023
Summary:

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: https://doi.org/10.1080/01441647.2023.2247165
Paper

Do Parcel Lockers Reduce Delivery Times? Evidence from the Field

 
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Publication: Transportation Research Part E: Logistics and Transportation Review
Volume: 172 (2023)
Publication Date: 2023
Summary:

Common carrier parcel lockers have emerged as a secure, automated, self-service means of delivery consolidation in congested urban areas, which are believed to mitigate last-mile delivery challenges by reducing out-of-vehicle delivery times and consequently vehicle dwell times at the curb. However, little research exists to empirically demonstrate the environmental and efficiency gains from this technology. In this study, we designed a nonequivalent group pre-test/post-test control experiment to estimate the causal effects of a parcel locker on delivery times in a residential building in downtown Seattle. The causal effects are measured in terms of vehicle dwell time and the time delivery couriers spend inside the building, through the difference-in-difference method and using a similar nearby residential building as a control. The results showed a statistically significant decrease in time spent inside the building and a small yet insignificant reduction in delivery vehicle dwell time at the curb. The locker was also well received by the building managers and residents.

Recommended Citation:
Ranjbari, A., Diehl, C., Dalla Chiara, G., & Goodchild, A. (2023). Do Commercial Vehicles Cruise for Parking? Empirical Evidence from Seattle. Transportation Research Part E: Logistics and Transportation Review, 172, 103070. https://doi.org/10.1016/j.tre.2023.103070 
Paper

The Isolated Community Evacuation Problem with Mixed Integer Programming

 
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Publication: Transportation Research Part E: Logistics and Transportation Review
Volume: 161
Pages: 102710
Publication Date: 2022
Summary:

As awareness of the vulnerability of isolated regions to natural disasters grows, the demand for efficient evacuation plans is increasing. However, isolated areas, such as islands, often have characteristics that make conventional methods, such as evacuation by private vehicle, impractical to infeasible. Mathematical models are conventional tools for evacuation planning. Most previous models have focused on densely populated areas, and are inapplicable to isolated communities that are dependent on marine vessels or aircraft to evacuate. This paper introduces the Isolated Community Evacuation Problem (ICEP) and a corresponding mixed integer programming formulation that aims to minimize the evacuation time of an isolated community through optimally routing a coordinated fleet of heterogeneous recovery resources. ICEP differs from previous models on resource-based evacuation in that it is highly asymmetric and incorporates compatibility issues between resources and access points. The formulation is expanded to a two-stage stochastic problem that allows scenario-based optimal resource planning while also ensuring minimal evacuation time. In addition, objective functions with a varying degree of risk are provided, and the sensitivity of the model to different objective functions and problem sizes is presented through numerical experiments. To increase efficiency, structure-based heuristics to solve the deterministic and stochastic problems are introduced and evaluated through computational experiments. The results give researchers and emergency planners in remote areas a tool to build optimal evacuation plans given the heterogeneous resource fleets available, which is something they have not been previously able to do and to take actions to improve the resilience of their communities accordingly.

Recommended Citation:
Krutein, K. F., & Goodchild, A. (2022). The isolated community evacuation problem with mixed integer programming. In Transportation Research Part E: Logistics and Transportation Review (Vol. 161, p. 102710). Elsevier BV. https://doi.org/10.1016/j.tre.2022.10271
Paper

Testing Curbside Management Strategies to Mitigate the Impacts of Ridesourcing Services on Traffic

 
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Publication:  Transportation Research Record: Journal of the Transportation Research Board
Publication Date: 2020
Summary:

Increased use of ridehailing leads to increased pick-up and drop-off activity. This may slow traffic or cause delays as vehicles increase curb use, conduct pick-up and drop-off activity directly in the travel lane, or slow to find and connect with passengers. How should cities respond to this change in an effort to keep travel lanes operating smoothly and efficiently? This research evaluates two strategies in Seattle, WA, in an area where large numbers of workers commute using ridesourcing services: (i) a change of curb allocation from paid parking to passenger load zone (PLZ), and (ii) a geofencing approach by transportation network companies (TNCs) which directs their drivers and passengers to designated pick-up and drop-off locations on a block. An array of data on street and curb activity along three study blockfaces was collected, using video and sensor technology as well as in-person observations. Data were collected in three phases: (i) the baseline, (ii) after the new PLZs were added, expanding total PLZ curb length from 20 ft to 274 ft, and (iii) after geofencing was added to the expanded PLZs. The added PLZs were open to any passenger vehicle (not just TNC vehicles), weekdays 7:00–10:00 a.m. and 2:00–7:00 p.m. The results showed that the increased PLZ allocation and geofencing strategy reduced the number of pick-ups/drop-offs in the travel lane, reduced dwell times, increased curb use compliance, and increased TNC passenger satisfaction. The two strategies, however, had no observable effect on travel speeds or traffic safety in the selected study area.

Recommended Citation:
Ranjbari, Andisheh, Jose Luis Machado-León, Giacomo Dalla Chiara, Don MacKenzie, and Anne Goodchild. “Testing Curbside Management Strategies to Mitigate the Impacts of Ridesourcing Services on Traffic.” Transportation Research Record, (October 2020). https://doi.org/10.1177/0361198120957314.