The 11th Street Bridge Park will be roughly the size of 3 football fields placed end-to-end. The Park will be built on the original pillars of the old freeway bridge crossing the Anacostia River between Wards 6 and 8 and will also connect to a new 16-foot-wide pedestrian and bicycle path that links with the Anacostia River trail [7]. Construction will begin in late 2026 with an expected park opening in 2028.

Our study aims are threefold: (1) to determine the impact of the 11th Street Bridge Park project on the built environments of Wards 6 and 8 that are within the sampling area (1-mile radius) surrounding the new park, (2) to determine the influence of this project on spacio-behavioral characteristics of the park itself, as well as of the sampling areas of Wards 6 and 8 surrounding the park, and (3) to determine the impact of the 11th Street Bridge Park project on individual- and family-level lifestyle behavior changes, as well as on perceptions of neighborhood safety and social connectedness, food security, and gentrification, using an intergenerational approach to gain perspectives across the life course.

The project is led by investigators from the Milken Institute School of Public Health at the George Washington University, along with investigators from 2 other schools of public health at the University of Maryland and Brown University. These academic institutions will then join together with several community partners both west and east of the Anacostia River to execute the project aims (Figure 2).

Building Bridges Across the River (BBAR) is a nonprofit organization housed in Ward 8 that, in collaboration with the District Department of Transportation, oversees the 11th Street Bridge Park in achieving the following primary goals: (1) to build a healthy community in the neighborhoods surrounding the Park, (2) to restore health to the Anacostia River, (3) to enhance connection between the Wards 6 and 8 communities, and (4) to become an anchor for equitable and inclusive economic development in the surrounding neighborhoods.

Joining forces with BBAR is a second nonprofit community organization, the Far Southeast Family Strengthening Collaborative (FSFSC). The mission of the FSFSC is “to act as a catalyst to develop, nurture, and sustain partnerships of residents, agencies, and institutions in the Southeast community and to create a healthy socioeconomic environment through which every child and family has an opportunity to achieve their maximum potential and to lead a productive life.” Among its many programs and services, the FSFSC maintains a Community Engagement Team. Through its projects and activities, the Community Engagement Team strives to build community capacity and bring families together to strengthen community networks. To that end, the FSFSC and the Community Engagement Team provide key elements to our study in their mission and values surrounding health promotion and human and community capital development. The FSFSC and their partner west of the river (Edgewood/Brookland Family Support Collaborative) will assist us in the identification and recruitment of families to participate in aim 3 of this project. In addition, we plan to train and use young people aged 18-25 years, participating in the Community Engagement Team’s Workforce Development Program, as paid community-based research assistants.

Finally, we have recently partnered with the Anacostia Parks and Community Collaborative, which is a network of community leaders and organizations working together to make the Anacostia River and its park system the best possible resource for residents of Wards 7 and 8 in the District of Columbia. The Anacostia Parks and Community Collaborative will continue to advise us in our selection of parks, playgrounds, and trails for auditing in addressing aims 1 and 2.

We plan to use census tracts within a 1-mile radius of the Bridge Park as our study area (Figure 3). Mapping techniques using RStudio (Posit) and ArcGIS were used to define this study area, as well as 2 comparison census tracts in Ward 8 and 1 comparison tract in Ward 7 that are not expected to be affected directly by the Bridge Park. Past research focused on urban built environments (including both food and park space environments) uses a 1-mile radius, as this is commonly defined as a feasible and 10-minute accessible walkability radius among diverse urban populations [18,19].

We plan a quasi-experimental longitudinal study with data collection occurring before the construction of the Bridge Park (baseline) and then once per year (April-October) over 3 years. We will use objective environmental audits and ArcGIS monitoring to address changes in the spacio-physical and spacio-behavioral characteristics of the study area surrounding the Bridge Park and will also rely on device-based and self-reported data from 300 family clusters to determine behavioral changes in physical activity and diet, as well as in perceptions of neighborhood safety, food security, and social capital resulting from the Bridge Park construction. Importantly, we will also monitor several objective indicators and self-reported perceptions of gentrification throughout the study to determine their influence on our environmental, social, and behavioral outcomes of interest. Table 1 provides a list of study variables, along with their method of assessment and timing of assessment.

We plan to recruit 300 family clusters, distributed equally within the census tracts comprising the study area and the comparison tracts. Each family cluster will comprise at least a parent or guardian and 1 child aged 10-15 years of age. To ensure an adequate representation of older participants, we will also enroll a grandparent or other older (>60 years) household member if available. Thus, family clusters will have no fewer than two members and no more than three members from different generations. To be eligible for the study, families must live within the census tracts surrounding the 1-mile radius of the Park (the study area) or in one of the comparison communities, with plans to remain in their residence over the subsequent 3-4 years. Children will be aged 10 to 15 years, which will allow for the accurate self-report of the behavioral variables of interest and will allow us to follow adolescents to age 18 without changing surveys. Adults will be >18 years of age, with no upper age limit.

Study participants will be recruited from community centers, after-school programs, the Children’s Hospital clinic in Ward 8, the DC Healthy Community’s website, churches, and other religious establishments. We will advertise (in English and Spanish) through newspapers, fliers, and social media (X [X Corp] @DCBridgePark and Facebook), as well as by newsletter and in-person visits. To ensure that our eligible study samples are representative of their ward population, we will compare our enrolled study sample with ward-specific census data and then use more targeted recruitment methods if supplementation is needed. The FSFSC currently works with over 800 families within Wards 7 and 8; the Edgewood-Brookland Family Support Collaborative serves over 200 families in Wards 5 and 6; while the Bridge Park newsletter currently reaches about 8200 households within Wards 6, 7, and 8. An enrollment goal of about 5 families per month per ward should allow us to meet our recruitment goal.

For ArcGIS, we will use secondary data sources from Open Data DC and ParkServe about our spacio-physical characteristics of interest (playgrounds, green spaces, hiking trails, sidewalks, food vendors, community gardens, corner stores, etc) to track changes in these features within the study area and the comparison areas before and after Bridge Park completion. We will also analyze raster data from satellites to track greater environmental changes related to air pollution and greenness. Change detection analyses, using pretrained deep learning models in ArcGIS Pro 3.5, can describe and quantify differences between images of the same area at different times. The output from change detection is a “difference raster” where each pixel contains the type or magnitude of change. We plan to supplement these data with those from the DC Office of Urban Agriculture and the DC Office of Planning, Food Policy Division, in assessing the food environment.

The System for Observing Play and Recreation in Communities [20] is a validated direct observation audit tool for assessing park and recreation areas, including the socio-physical characteristics (eg, accessibility, usability, safety, supervision, and organization) of the spaces, as well as the socio-behavioral characteristics (eg, use of specific features by estimated age, sex, and ethnic groupings). The System for Observing Play and Recreation in Communities will be supplemented with the Physical Activity Resource Assessment audit instrument, which addresses the presence and quality of various park and playground amenities (tennis courts, ballfields, drinking fountains, picnic tables, and trash receptacles) [21]. Audit data will be collected at baseline and then once per year (controlling for seasonality) over 3 years by pairs of observers over the course of one week. Data will be collected 3 times/day on 4 days of the week (2 weekdays and 2 weekend days) and entered directly into Microsoft spreadsheets by trained research assistants. We have identified 9 park areas to be audited—3 in our study census tracts west of the Anacostia River (Virginia Ave SE Park, Garfield Park, and Marion Park/Providence Park); 3 in the study tracts east of the river (Anacostia Park [2 locations] and Berry Farm); and 1 park in each of the 3 comparison tracts (Oxon Run [2 locations] and Marvin Gaye Park).

We will assess physical activity in each family cluster once per year over 3 years using both device-measured and self-reported approaches. Participants will first wear a Fitbit for 4 weeks, after which they will complete the self-reported physical activity survey that captures the previous 7 days. In this way, we will have some temporal overlap between device-measured and self-reported physical activity.

Step counts represent the fundamental unit of human movement; they are intuitive and easily understandable, and they translate well into public health recommendations [22]. Steps per day will be collected via Fitbit Charge 2 devices over 4 weeks (controlling for seasonality). Fitbit devices provide a valid and reliable measurement of daily step count as an estimate of accumulated physical activity in children, adolescents, and adults over longer periods of time [23]. Fitbits were chosen to minimize participant burden (eg, ability for family to charge and sync devices themselves at home) over extended wear periods. Moreover, adherence to wearing a Fitbit is often greater than that with accelerometers because there is no need to remove it from the wrist [24]. Participants will be instructed to wear the devices on the nondominant wrist at all times, including when they sleep, shower or bathe, or swim. Each Fitbit will be assigned a unique numeric identifier. We will create a generic account for each profile before providing it to participants during their scheduled baseline visit. Profiles will be linked to Fitabase (Small Steps Labs, LLC), a web-based interface that allows remote access and data download of participants’ Fitbit data. Similar to other studies, we will include all days with >599 daily minutes of waking wear time within each participant’s 4-week study protocol and a minimum of 1000 steps/day [25]. Valid wear time will be defined as having had at least 4 days of wear (3 weekdays and 1 weekend day) per week.

Self-reported physical activity in adults will be assessed with the International Physical Activity Questionnaire–Short Version [26]. This 7-item self-administered questionnaire queries physical activities performed during the previous 7 days. Frequency (days), duration (min), and intensity (metabolic equivalents of tasks [METs]) of moderate- and vigorous-intensity activities (work or leisure time), as well as of walking and sitting, are combined to derive a volume measure, expressed as MET-min/week. Self-reported physical activity among children and adolescents will be assessed using the self-administered Physical Activity Questionnaire for Older Children (PAQ-C) [27] and the Physical Activity Questionnaire for Adolescents (PAQ-A) [28]. The PAQ-C is a 9-item, 7-day physical activity recall instrument designed for use in elementary and middle school-aged children. Each item is scored on a 5-point scale to derive a composite score, with the mean of the composite score being the PAQ-C summary score (ranging from 1 to 5). The PAQ-A is a slightly modified version of the PAQ-C (without the “recess” item) designed for high school students. It is administered and scored in a similar manner as the PAQ-C, except that the composite score is based on 8 items rather than 9. Summary scores for the PAQ-A also range from 1-5. The International Physical Activity Questionnaire, PAQ-C, and PAQ-A were chosen over other surveys, such as the Global Physical Activity Questionnaire [29] and the ACT24 (activities completed over 24 hours) tool [30], because there are validated versions for adults, adolescents, and children, and they assess the previous 7 days rather than only 24 h (thus allowing for a fuller temporal overlap with the Fitbit data).

All researchers and research assistants have taken the Human Investigations Training Course either online (through the National Institutes of Health [NIH]) or in person through George Washington University. Eligible participants will scan the QR code from the study advertisement to gain access to and sign the consent form. The parent or a guardian will be provided with the study information required for informed consent and will decide whether to allow their child to participate. Study information will also be described in age-appropriate terms to the eligible child, who must verbally express their willingness to participate. Participants can also complete all study surveys via REDCap. All surveys used in this study have been translated into Spanish. Other than census tract number, age, sex, and race, we will not gather any identifiable information on participants that could link them to survey responses. Families will each receive up to US $300 in gift cards (US $100 gift card/year) for their participation and return of Fitbits.

Study data will be managed using REDCap electronic data capture tools hosted at George Washington University. REDCap is a secure, web-based application designed to support data capture for research studies, providing: (1) an intuitive interface for validated data entry, (2) audit trails for tracking data manipulation and export procedures, (3) automated export procedures for seamless data downloads to common statistical packages, and (4) procedures for importing data from external sources. REDCap uses various methods to protect and secure data stored in the database. All electronic data will be stored on a password-protected computer. No individuals, other than the professionals directly involved in the study, will be allowed to read data forms. Investigators will be required to respect the confidentiality code. No subjects are identified by name in any of the published literature and only by code in major data storage areas. The master list of participants and ID numbers will be kept in a password-protected computer file on a secure network drive at George Washington (GW). To date, we have never had a violation of confidentiality.

As stated previously, we will leverage a naturally occurring intervention to study changes in the built environment and their effects on several domains of community health. Typically, built environment interventions focus on a single environmental change (eg, complete streets, biking or walking trails, or traffic calming measures) and a single outcome (eg, physical activity, walkability, or food access). Several systematic reviews examining the effects of such changes in the built environment on community physical activity patterns generally report positive findings in both adults and in children [43-45]. We plan to examine several concomitant environmental changes resulting from the new Bridge Park and their effects on multiple behavioral and social indicators of health. One systematic review of self-described “natural experiments” (involving policy and/or environmental changes) cited the utility of such studies for examining complex and multifactorial public health issues (eg, obesity prevention) and for providing “real-world” evidence in situations in which a large randomized-controlled trial is not feasible or ethical [45]. Natural experiments often are criticized for their inability to eliminate bias—particularly bias due to confounding [46], lack of a control group [45], or weak evaluation methods [47]. Our study addresses these limitations by (1) controlling for multiple sources of known and measurable confounding variables (notably, indicators of gentrification) using sophisticated multivariable statistical techniques, (2) using comparison communities not expected to be directly affected by the Bridge Park, and (3) using a longitudinal study design with multiple data collection points over 3 years.

Our approach is consistent with a systems-level ecological model and the PSE public health practice model that both emphasize multiple-sector, multiple-level action that directly affects important social drivers of health [16]. Expertise from investigators at 3 schools of public health, combined with that of our community partners, adds a substantial level of joint scientific- and practice-based rigor that will use a range of objective and self-reported methods to collect primary data, which will be supplemented with secondary data from publicly available sources managed by DC government and the US Census.

We anticipate that the environmental outcomes (spacio-physical and spacio-behavioral changes) proposed in aims 1 and 2 will demonstrate improvements within 1 year post completion within the study area, but not in the comparison census tracts. A 20% improvement in daily step counts would have strong clinical and public health significance [48] and may take up to 2 or 3 years to observe. Meaningful improvements in food choices and perceived food security, social capital, and neighborhood safety may also take up to 3 years to occur. With regard to changes in perceived gentrification, we note that there will be anticipated benefits to the Ward 8 community resulting from the ongoing work of BBAR and their Equitable Development Plan. These benefits include greater access to affordable housing, workforce development, and small business growth, which are important social drivers of health and human capital. Whether these benefits will be distributed equally across the different census tracts in Ward 8 is not clear. The BBAR staff will collect data on these outcomes and provide us with annual reports so that we can account for any effects that changes in these factors may have on our behavioral health outcomes.

There are also some potential challenges that need to be considered with this study. Recruitment of participants from low-resource areas is an issue in any study. Should we fall behind in our recruitment targets, we will work closely with BBAR and the FSFSC’s Community Engagement Team to devise targeted strategies for enhancing recruitment in the different study census tracts. Training and hiring research assistants from the FSFSC Workforce Development Program (who are members of the community) and a research assistant who is fluent in Spanish will also help us achieve our recruitment goals. Maintaining the study sample for aim 3 over 3 years may be challenging due to changes in residence or attrition. First, our chosen statistical method (linear mixed effects model) is fairly robust in handling certain types of missing data (eg, missing at random). Additionally, we use a preventive strategy during the screening process to identify any barriers (ie, anticipated relocation outside of the study area) that may hinder a participant from completing the study. We take note of these potential barriers and use participant-targeted approaches to address them to minimize the risk of attrition. As important is the presence of the entire research staff within the communities (hosting meetings and giving talks) as much as possible. We have been successful in retaining participants in our past community intervention studies by maintaining close contact with them. Study visits for Fitbit set-up will be scheduled based on the participants’ availability, with reminders of upcoming visits and data collection periods being texted or emailed. If a study visit is missed or canceled, it will be rescheduled within 1 week.

Construction delays may also be a challenge to completing our study aims promptly. We do not foresee problems collecting baseline data within our proposed timeline, and, if necessary, we could shorten our follow-up period if construction is delayed. Even with a shortened follow-up, improvements in the built environment features (aims 1 and 2) and step counts (aim 3) should be apparent, even though health status, social capital, or policy changes may take longer.

The ability to synchronize Fitbit data with a cellphone requires participants to have internet. If there is limited or no internet within the participants’ home, we will encourage them to go to the local public library or recreation center, where internet is available for free. Further, there is often conflict on whether to use research-grade or commercial wearable trackers for the objective measurement of physical activity. Whereas Fitbit tends to overestimate steps relative to Actigraph (Ametris) accelerometers, there is evidence of adequate agreement between devices [49]. There is also concern that proprietors of wearable devices will change the algorithms for converting raw data into motion counts over time; however, this issue also occurs when using research-grade accelerometers. Fortunately, any changes in algorithms with the Fitbit will likely affect only the calculations of moderate-to-vigorous physical activity and sleep and not step counts.

By leveraging a large, naturally occurring environmental improvement project that will link 2 socioeconomically different wards in Washington, DC, we can provide evidence of the positive and unintended consequences of the 11th Street Bridge Park to the communities affected by it. Given the consistently strong relationship observed between poverty, low access to health-promoting environmental features, and poor health, findings disseminated from this project could help to inform other urban design projects to provide equitable and sustainable benefits to everyone living in the community.