In 2020, we conducted web searches to locate US municipal Vision Zero initiatives. The search list was based on the US Census of 788 incorporated places with a population size of at least 50,000 at any time between April 2010 to July 2019.¹⁴ Similarly, in 2021 we conducted web searches to find US Vision Zero initiatives supported by metropolitan planning organizations (MPO). MPOs are planning organizations that provide the coordination of transportation, infrastructure, and land use in the US.¹⁵ They have their own structure and may be administered independently or within a municipality, county, highway commission, or some other government organization. The search list was based on the 408 MPOs identified by the US Department of Transportation and Bureau of Transportation Statistics.¹⁵ A protocol for searching was developed, piloted, and refined, with more details provided elsewhere.¹⁰ From these searches, we identified 86 municipal (out of 788 municipalities, 10.9%)¹⁰ and 16 MPO (out of 408 MPOs, 3.9%) initiatives. We also identified several other initiatives through independent searching using the terms “Vision Zero plan” that were not specifically municipal or MPO level but were generally at a larger, regional level.

The municipal and regional (i.e., MPO, transportation planning organization, Council of Governments, and county level) Vision Zero initiatives identified from the searches, described in the prior paragraph, provided the sample from which we then sought to capture Vision Zero plans published at any time through 2022. A protocol and plan abstraction form were developed, piloted, and refined. For the abstraction, we searched the plan for “health” and “public health” (as well as other health-related abbreviations) throughout the document. We identified and coded whether public health officials were involved in the creation of the plan (i.e., plan development) or whether public health was part of the principles guiding the plan’s foundation (Supplemental Table 1). Public health involvement in implementation was assessed through the abstraction of goals, objectives, and actions. Each plan was abstracted by one of two trained coders and checked by a second trained coder.

We focused only on the first Vision Zero plan published by an initiative and therefore did not include plan updates. In total, we identified 64 municipal and 21 regional first-time Vision Zero plans. Among the regional plans, the specific designations varied: 8 counties, 5 MPO/counties, 4 MPO, 2 transportation planning organizations/agencies, and 1 Council of Governments. All regional plans were abstracted (n=21). The municipal plans were sorted by year and every third plan was sampled for abstraction (n=22).

The municipal and regional Vision Zero initiatives identified from the searches provided the sample from which we invited a subset of Vision Zero coordinators for an in-depth interview. We chose initiatives from diverse locations across all five US Census regions.¹⁶ For the municipalities, we required a population size of at least 100,000 as there were so few initiatives in smaller populated municipalities.¹⁰ The interview guide, which is described in a prior publicatoin,¹⁰ was designed to better understand the origin, activities, and key groups involved in Vision Zero initiatives. This study specifically analyzed responses from questions asking about whether public health officials were involved in the Vision Zero initiatives and, if so, to describe how. The interview procedures and guide were reviewed by the University of North Carolina – Chapel Hill Institutional Review Board before initiation.

Municipal interviews were conducted between December 2020 and June 2021 and regional interviews were conducted between October 2021 and December 2021. Interviews were recorded, with permission, and transcribed verbatim. A codebook was developed from the interview questions and then expanded as themes emerged. The transcripts were entered into ATLAS.ti (version 8) for coding and analysis. The data were reviewed line-by-line with codes assigned by two team members and discrepancies were resolved through consensus. To examine the alignment between public health efforts within Vision Zero initiatives and foundational public health functions, we assigned findings to the updated ten Essential Public Health Services framework, describing where and how Vision Zero work was related to and aligned with core public health functions.¹⁷

We identified a total of 64 municipalities with Vision Zero plans, of which a sample of 22 were abstracted, and 21 regional entities with Vision Zero plans. Plans were published between 2014 to 2022, with more first-time plans published in recent years (Supplemental Table 2). Plans were identified in all five US Census regions, with more municipal plans in the Pacific (36.4%) and South (36.4%), and more regional plans in the South (52.4%).

Most plans described key group involvement in developing the plan for both municipal (81.8%) and regional (100%) plans (Table 1). About two-thirds (67.4%) of the plans involved public health officials in the plan development, with a higher percentage for regional (76.2%) compared to municipal (59.1%) plans. Most plans described the principles forming the foundation of their plan (86.4% municipal, 81.0% regional). Only a few plans mentioned public health as part of its principles (22.7% municipal, 14.3% regional). Some examples included:

“The plan is underpinned by several key principles: Traffic deaths and injuries are a preventable, public health issue. Any traffic death is too many.” (Austin, TX; 2016)

Public health officials were specifically identified in the Vision Zero plan development process through community engagement (e.g., conducting community-oriented focus groups; 9.1% municipal, 33.3% regional) and providing data (22.7% municipal, 52.4% regional; Table 1). All plans included a description of goals, objectives, and/or actions. Public health was specifically referenced or officials were implicated in about half of the plans’ goals, objectives, or actions (45.5% municipal, 57.1% regional). They were also identified as responsible for several implementation tasks including future community engagement (31.8% municipal, 42.9% regional), future data efforts (40.9% municipal, 33.3% regional), and mentioned as a source of future funding (13.6% municipal, 4.8% regional). Specific detailed examples of current and future public health involvement in Vision Zero work, as recorded in the plans, are provided in Table 2.

Since we abstracted a sample of municipal Vision Zero plans (22 of 64), we compared characteristics (e.g., plan publication year, number of plans published, US Census region,¹⁶ US Census population from 2019) of those selected to those not selected and highlighted absolute differences of at least 5%. We found a relatively similar distribution of plans by year of publication (Supplemental Table 2). We only abstracted the first plan and found that a lower percentage of municipal plans abstracted had second or third plans compared to those not abstracted (9.0% vs. 28.6%). Fewer abstracted municipal plans were from the Midwest (4.5% vs. 16.7%) and West (4.5% vs. 14.3%), and more municipal plans were from the Pacific (36.4% vs. 28.6%) and South (36.4% vs. 26.2%) census regions compared to plans not abstracted. Abstracted municipal plans were less likely to have a population size of at least 150,000 compared to those that were not abstracted (59.1% vs. 78.6%).

The in-depth interviews provided more context around public health involvement in Vision Zero initiatives. We conducted 12 interviews with municipal-level coordinators and 10 interviews with regional-level coordinators (Supplemental Table 3). The majority of both the municipal and regional level initiatives were located in the South (33.0% municipal, 40.0% regional) and West (33.0% municipal, 40.0% regional) census regions. Almost half of both municipal (42.0%) and regional (40.0%) level initiatives participating in the interviews had Vision Zero plans.

Most initiatives either involved or planned to involve public health officials at the local level. However, one municipal Vision Zero coordinator stated, “Our state Department of Health is very involved in transportation issues.” They went on to describe key state-level involvement in training, education, and funding for their Vision Zero initiative.

We categorized public health involvement in Vision Zero initiatives according to the ten Essential Public Health Services framework.¹⁷ Interviewers discussed how public health officials were involved in their Vision Zero initiative with quotes that aligned with eight services: assess and monitor population health; investigate, diagnose, and address health hazards and root causes; communicate effectively to inform and educate; strengthen, support, and mobilize communities and partnerships; create, champion, and implement policies, plans, and laws; enable equitable access; build a diverse and skilled workforce; and improve and innovate through evaluation, research, and quality improvement (Supplemental Table 4). Of the ten essential services, public health was not identified to utilize legal and regulatory actions nor to build and maintain a strong organizational infrastructure for public health.

Several Vision Zero initiatives did not presently incorporate public health officials into their work. Reasons included that the pandemic took time spent on this initiative, lack of staff qualified to act as a liaison, and staff turnover such that those previously involved were not replaced. Two regional entities described less emphasis on current public health involvement. One interviewee stated, “We work closely with our public health department when I worked for a city and I was part of Public Works, and we work closely with Planning as well. … For us, because we’re an MPO, [it] is a bit different, right? We do have, you know, partnerships with public health agencies in our region. They are …practitioners who attend our working group meetings…. They’re concerned about bicyclists and pedestrian safety as well. They have high injury networks that they have developed, and so the partnerships exist but you have to think, again, at a scale like ours, of [xx] million people…” [the partner engagement is less]. Another interviewee stated, “I wouldn’t say it’s something that… I have heard emphasized a lot. It’s something that I would like to see emphasized more, not just in our work but in planning, and specifically transportation planning generally, but… we don’t have anybody on staff who’s got a public health or epidemiology skill set. I would love to have that capability. I think it’s really important and I think it is kind of where we’re going. But we’re not there yet.”

While public health officials may serve different roles at a local compared to a regional or state level, public health can generally be framed according to the major functions described by the ten Essential Public Health Services.¹⁷ This framework includes equity placed in the center of the ten functions broadly grouped into (i) assessment, (ii) policy development, and (iii) assurance. From the interviews, we assigned functions described or assigned to public health officials using this framework and identified quotes aligning with eight of ten core functions. Quotes from the Vision Zero plans also supported many of these functions. Next, we further synthesize and discuss key takeaways according to these functions.

This project had several strengths and limitations. First, we searched systematically for US municipal and regional Vision Zero initiatives and their plans. Nevertheless, we still may have missed an initiative or plan based on dates of our searches, particularly from a Vision Zero initiative in the early stages of development. However, our identification of plans and initiatives are similar to methods reported by others with a differing methodologic approach over an overlapping time period.²³ Second, while we abstracted all first-time regional Vision Zero plans, we sampled municipal plans for abstraction. While the year of plan publication was similar, there were some differences in the number of plans, US census region, and population size between plans selected compared to those not selected for plan abstraction (Supplemental Table 2). Third, reliance on plans to understand the contribution of public health may not capture the full breadth of their engagement or the specific types of public health partners involved in the initiative. The addition of in-depth interviews helped to provide further context and understanding of public health involvement in Vision Zero. We encourage initiatives to provide more detail in plans about the involvement of experts in their plan development. Fourth, although we aimed to include a diverse set of initiatives, the interview sample may not reflect the breadth of Vision Zero initiative experiences since by design we did not include initiatives in the early development phase and focused on initiatives at municipalities with a population size of at least 100,000 persons. Further exploration would be worthwhile to identify adaptations of Vision Zero with small-to-mid-sized municipalities.

While public health and transportation are two distinct disciplines, both rely on community engagement, use data to inform decisions, pilot projects to inform future decisions, and ultimately work to keep populations safe.^{17, 24, 25} We found public health entities were involved in assessment, policy development, and assurance for Vision Zero initiatives. Integration of public health into Vision Zero efforts will enhance the success of overlapping goals from each discipline related to improved public safety and ultimately a reduction in serious and fatal traffic-related crashes.