June 28, 2019 BY Veronica Vanterpoolin Case Studies, News, Webinars

Linking Transportation & Health Systems: Pioneering Collaborative is Model for Vision Zero

Access to comprehensive and accurate data is critical to Vision Zero success. Addressing the public health crisis of nearly 40,000 preventable traffic fatalities annually in this country requires a comprehensive understanding of the who, what, where, when and why of this tragic toll. While data collected from police reports helps answer some questions, it doesn’t fill in all the blanks. This can lead to under-reported injuries that can result in a lack of services and safety interventions for some of our most vulnerable road users.

Thankfully, a new effort - Vision Zero Injury Prevention Research Collaborative (VZIPR), being led jointly by the San Francisco Department of Public Health's Program on Health, Equity and Sustainability (SFDPH-PHES) and Zuckerberg San Francisco General Hospital and Trauma Center (ZSFG) - is working to fill the data gaps in transportation-related injuries and deaths and ensure that all people, especially our most vulnerable, are counted. In our Is There a Doctor on Board one-hour webinar below, we hear from those leading this pioneering and transformative initiative to systematically link police data with data from trauma centers to better capture traffic injuries and fatalities and more fully inform San Francisco’s Vision Zero priorities and investments.

San Francisco’s leaders view traffic injuries and deaths as a public health issue, according to Megan L. Wier, Director of SFDPH-PHES and the co-chair of San Francisco’s Vision Zero Task Force.

Image: SFDPH

City trauma surgeons respond to a serious traffic injury every 17 hours, and 500 people annually are hospitalized in the city’s public hospital with severe traffic injuries. In fact, Wier noted that roughly half of the patients seen at the trauma center are people injured in traffic collisions. These statistics are jaw dropping. But, also of concern is the significant percentage of these cases not captured in police reports, as is the case in most communities. This is how systemically linking police data and trauma data fills in the gaps. This is an important and new approach in the U.S. to get more comprehensive data to advance and target Vision Zero investments.

Filling in the Data Gaps

The data used in this project is pulled from two sources: Police Reported Injury Collisions (as is the main data source in most U.S. communities) and hospital medical records. While police data provides critical details on the location and characteristics of a crash, it is sometimes limited in capturing injury severity beyond what is visible and external to an officer at the scene of the incident, such as a broken bone or bleeding. Also, there seems to be an overall tendency of under-reporting at the scene of the incident. Analysis of San Francisco’s police and hospital data has shown that relying on police data can lead to under-reporting of injuries, particularly for pedestrians and bicyclists, who are less likely to file police reports when in a crash. Approximately 20% of pedestrian injuries and 25% of cyclist injuries seen at ZSFG were not included in police records.

Image: VisionZeroSF

On the other hand, hospitals and trauma centers have better tools to assess injuries and severity more comprehensively than police officers on the scene, so they’re more likely to recognize and capture in reports non-visible but serious injuries, such as concussions or internal bleeding, as well as being able to link interrelated health factors, such as disability status, demographics or homelessness that help contextualize injury impacts. The difference in measurement between the two data sets can be significant: in San Francisco, local police data can miss 24% - 39% of severe injuries suffered by pedestrians and bicyclists later captured at a trauma center or hospital. That’s a significant amount of under-reporting amongst our most vulnerable road users who are at greater risk on the streets due to a variety of factors including limited infrastructure investment and outdated policies.


This discrepancy makes it especially difficult to target inequities in traffic fatalities in communities of concern including older adults, non-English speaking populations, low-income or disabled individuals, minority populations and people experiencing homelessness.

Role of Public Health in Vision Zero

The medical community can play a pivotal role in Vision Zero. In addition to treating injuries and recommending prevention measures, trauma nurses, surgeons, epidemiologists and emergency room physicians are all reliable sources of injury prevention information to influence policymakers, legislators and the media. They can educate these key influencers, help advocate effective policies and laws and partner on public education campaigns. These are examples of how medical professionals at the Zuckerberg San Francisco General Hospital and Trauma Center are engaged in the city’s Vision Zero efforts, according to Dr. Rebecca Plevin, assistant professor of Trauma and Critical Care at ZSFG.

Essential to this data linking project is the city’s full-time Vision Zero epidemiologist, a position funded by the city’s transportation agency, which sees the value in working closely with the public health agency. Shamsi Soltani, SF’s Vision Zero epidemiologist, manages the Transportation-related Injury Surveillance System (TISS) database, and spends time working at ZSFG, offering direct access to colleagues in the medical field. The TISS is a pivotal piece of this initiative: it is a central database that gathers and links hospital, police, emergency response and other data from city and county agencies to help paint a complete picture of the "geographic distributions, causes, costs and consequences of transportation-related injuries in San Francisco."

Soltani’s role as an epidemiologist is integral to this work; she looks at the linked police and trauma center/hospital data and fills in the data gaps by comparing who was transported to the hospital via EMS but not reflected in police reports. Conversely, police data provides important information on where the crashes and injuries are happening and details on the crash characteristics (e.g. speeding, red-light running).

All publicly releasable data is then geocoded on San Francisco’s publicly available database mapping platform, TransBASESF. In addition to showing where injuries are occurring, the mapping tool also allows you to view dozens of additional layers, including land use, demographics such as individuals with a disability, older adults, people of color and percent of households below the poverty line. Another layer, Vision Zero Fatalities Tracking, measures annual fatalities each year since Vision Zero was adopted in San Francisco in 2014 to year-to-date 2019. This data is essential to updating the city’s High Injury Network (HIN), which helps the city recognize the areas with high numbers of fatalities and severe injuries to best focus its efforts on the most problematic areas. It is important to note and praise San Francisco's effort as the first such endeavor in the country to systematically link police and trauma data, map it and analyze it to advance Vision Zero.

Using Data to Prioritize Improvements, Prepare for Emerging Trends

In addition to being a national leader on data, San Francisco has also led the way in prioritizing health equity into its Vision Zero planning and efforts. TransBASESF, coupled with the city’s High Injury Network, provides integral data on fatalities, severe injuries and street conditions specifically in communities of concern (CoC), which include higher densities of older adults, people with disabilities, low-income residents and communities of color. Analysis of the TransBASESF database, for instance, shows that one-third of injuries of seniors and those with disabilities occur on streets that are “traffic calmable” - residential streets eligible for safety improvements in the city’s Traffic Calming Program. And even though only 31% of San Francisco’s surface street network falls within CoC, 51% of the High Injury Network is in CoC. Having this important data overlay helps the city to target its Vision Zero investments on streets and corridors where vulnerable individuals are most at risk.


The data can also shape policy and pilot programs and improve communications across departments, including managing new mobility options such as ride sharing, e-scooters and autonomous vehicle pilots. For instance, new questions were added to SF’s Vision Zero Injury Prevention Research Collaborative trauma registry to better understand the impact of e-scooters, e-bikes and other mobility services on traffic injuries, as well as to guide interdepartmental communication and policy development on these emerging options.

Value-Added Partnerships

A Core Element of Vision Zero is its interdisciplinary, systems-based approach to an admittedly complex problem. An example of this is San Francisco’s acknowledgement of and action in treating traffic deaths as a public health issue, helping move beyond the traditional transportation silo into an interdisciplinary realm, involving health, policymaking and other disciplines. The Vision Zero Injury Prevention Research Collaborative brings transportation planners and engineers together with new partners, including professionals at trauma centers, as well as law enforcement, researchers and advocates.


Additionally, partnering with trauma centers on traffic safety provides access to new avenues of research, exposes and cultivates a new audience of clinicians, hospital staff and others in the medical field to Vision Zero and allows for the development of injury severity and cost analysis data to bolster requests for Vision Zero funding investments and policy change.

Linking Transportation Systems to Health in Your Community

While the scale of this initiative in San Francisco may seem daunting to a smaller community, there are key takeaways that can make the Vision Zero Injury Prevention Research Collaborative a viable initiative in any-sized community:

  • Identify and work with new partners, including champions within hospitals and trauma centers. Data sharing is essential to this effort, so partnering with someone dedicated to getting and sharing data is key.
  • Collaboration is a must. This Research Collaborative became elevated, funded and institutionalized as part of San Francisco’s commitment to Vision Zero in 2014 and a multi-sector approach was mandated by a mayoral directive. The relationships that had already been cultivated among transportation planners and engineers, advocates, health and medical professionals at the onset of Vision Zero in SF were instrumental to the successful collaboration to address data gaps and under-reporting.
  • Start with existing data. Understand different injury data sources (e.g. policy data and hospital data) and the deficiencies and limitations of existing data. One key piece of advice is to not let gaps in data paralyze action. Instead, improving and addressing data gaps should be an ongoing, iterative process. Work with data you do have, and improve it over time.
  • Emphasize the added value and understanding gained from data linkage. For instance, San Francisco could use data to advance its health equity focus amongst vulnerable populations most impacted by transportation network.
  • Align with funding opportunities. Look for opportunities to fund work – what gets funded, gets continued. And be clear that investment to link data across sectors is modest compared to millions invested in infrastructure and in the unfortunate aftermath of treating those injured and killed in traffic crashes.

Getting to zero requires collaboration, new and dynamic approaches, data and focus. There are myriad benefits to data sharing across departments and agencies. In fact, data integration and sharing is the bedrock of NYC’s Vision Zero taskforce and to Vision Zero efforts in cities, across the U.S., including Denver, Boston, NYC, Portland, Seattle and many others. With modest investments and a largesse of commitment, your community can link transportation systems to health too for safer results.

Related News

Calls for Action Heighten on World Day of Remembrance
From Portland to Pittsburgh, Louisville to Las Vegas, and Madison to Montgomery County, Maryland, a record-number of people joined forces to call for an end to the tragic and preventable roadway safety crisis across the nation. On this World Day of Remembrance for Road Traffic Victims (WDoR), more than 75 communities organized rallies, memorial walks …

Calls for Action Heighten on World Day of Remembrance Read More »

Speed Matters: Using Safety Analytics to Fast-Track Projects to Manage Speeds
Managing speeds is a critical – if not the critical – strategy to advance Vision Zero. Recognizing this, communities are looking for ways to more rapidly pilot and implement effective actions to reduce speeds. And, fortunately, funding – including from the new federal Safe Streets and Roads for All (SS4A) grant program – is increasingly …

Speed Matters: Using Safety Analytics to Fast-Track Projects to Manage Speeds Read More »

Achieving Equity in Vision Zero Planning: A Framework for Transformative Change
In the U.S., BIPOC and low-income communities experience an alarmingly high and disproportionate burden of risk on our roadways. The need for change is urgent. And the opportunity is ripe for policymakers, roadway safety professionals and Vision Zero advocates to address this tragic – and preventable – racial and income gap in safety outcomes. Vision …

Achieving Equity in Vision Zero Planning: A Framework for Transformative Change Read More »

Scroll to Top