Safe System Success Stories: from Principles to Practice

We’re encouraged to see more communities evolving their early-stage Vision Zero work to a more in-depth, systemic approach that focuses on upstream road safety solutions and institutionalizing change. This broader Vision Zero approach builds on initial plans, policy language and attention to high-injury hot spots toward a more holistic Safe System approach that identifies and proactively addresses crash risks, preventing severe crashes before they happen.

On September 10, 2026, Vision Zero Network was proud to join the Insurance Institute for Highway Safety (IIHS) in co-hosting a webinar to showcase what this evolution to a Safe System approach looks like on the ground. Building on the newly released Safe System Success Stories — case studies developed by IIHS, Vision Zero Network, ITE, UNC Highway Safety Research Center, and Fehr & Peers — the conversation featured three agencies working to move the Safe System approach from principle into everyday practice: Arlington County, Virginia; Santa Rosa, California; and the Minnesota Department of Transportation.

The examples, from a dense inner-ring mid-Atlantic county, to a mid-size city in California's North Bay, to a Midwestern state whose transportation department maintains more than 10,000 miles of rural two-lane highway were united in making safety the default in how they plan, fund, and build.

It’s All About Physics

The Safe System approach is grounded in physics. Faster speeds and heavier vehicles mean more kinetic energy in a crash, and greater likelihood of serious injury.

Communities have three levers to pull to reduce serious injuries. Each one targets a different way that kinetic energy puts people at risk.

1. Exposure (how much people drive). Communities lower exposure by making it easier to get around without a car and by reducing how much people need to drive. Austin, for example, is reframing its long-range planning and development review around access and mode shift, expanding transit so fewer trips have to happen by car.
2. Severity (how fast vehicles travel and how heavy they are). Communities lower severity by setting speed limits to survivable levels and backing them with self-enforcing street design, so slower speeds happen by design rather than by enforcement. Cleveland, for example, scaled up speed tables citywide after a pilot brought average speeds down by nearly 8 mph.
3. Likelihood (how often road users come into conflict). Many crashes trace back to the moments where people and vehicles are allowed to cross paths. Communities lower likelihood by designing those conflicts out, separating road users in time or space. Philadelphia, for example, used road diets and separated bike lanes to cut conflict points and physically separate people walking and biking from traffic.

The strongest, most effective approaches pull all three levers at once, addressing the "trifecta" of exposure, severity, and likelihood together. These "safety multipliers" work because the pieces reinforce one another to deliver benefits greater than the sum of their parts. For example, a corridor redesign that replaces general traffic lanes with dedicated transit lanes, narrows the remaining lanes and adds median pedestrian refuges, and restricts left turns while adding leading pedestrian intervals pulls all three at once. The transit lanes shift trips out of private cars (exposure), the narrower lanes and refuges bring speeds closer to survivable levels (severity), and the turn restrictions and pedestrian intervals cut the points where people and vehicles conflict (likelihood).

Notably, the "answer" to improving road safety is not any single or even handful of countermeasures (though those are important). The significant and lasting safety gains come when regular decision making and policymaking change, when organizations move from one-off fixes reacting to individual problems toward consistent, systemwide change. 

IIHS’ Jessica Cicchino emphasized that a Safe System is about how tools and strategies are used, rather than the tools themselves. “Meaningful safety gains often come from changing the way that decisions are made, rather than just adding another project.”

Here's how three jurisdictions highlighted in Safe System Success Stories are moving from reactive to proactive safety approaches and starting to institutionalize these changes in their organizational culture.

Arlington County, Virginia: Proactive by Design

Christine Baker, Vision Zero Program Manager for Arlington County, described a program deliberately pivoting from reactive to proactive. The reactive work, like crash reviews and weekly crash tracking, is not going away, she noted, but it does not show the full picture. So Arlington layers two proactive moves on top of it. First, Arlington uses infrastructure, equity, exposure, and conflict data to flag risky conditions, like overly wide lanes, before a crash happens rather than waiting for a crash to prove the point. Second, when a treatment works in one place, the county scales it across whole corridors instead of fixing intersections one at a time.

"We look at systemic safety as you see a problem in one place, and then you try to fix it in all the other places like it. So we don't need to wait for a crash to happen to take action."

-Christine Baker, Arlington County

That scale-up mindset shows up most clearly in two types treatments Arlington took from a small pilot to standard practice.The first treatment is turn hardening, a low-cost treatment many agencies could use but don't. Arlington piloted hardened centerlines at five intersections, choosing sites by crash history, exposure, and geometry. The pilot worked, with 16% more cars turning below 10 mph, so the county expanded turn hardening to more locations. A companion downhill bike lane and right-turn conflict pilot, using flex posts and mini speed humps, got 34% more vehicles turning below 10 mph. Because right hooks are Arlington's most common bike crash type, turn hardening is now becoming a standard treatment. 

The second treatment is speed management, which follows the same pilot > learn > scale path. Because a county board moratorium blocked new permanent speed humps, staff used tactical, temporary versions as a way to reintroduce them and prove the case. Across three rounds of the pilot in 20 mph school-zone slow zones, screening candidate streets with data and then narrowing with lidar, the speed humps cut the share of cars going over 20 mph by 67%. Arlington is now working back toward permanent asphalt tables and cushions. The county also began installing school-zone speed safety cameras in three phases in fall 2024, and both driver speeds and crashes have declined in those corridors.

Baker suggests thinking of the Safe System approach as layers of safety nets, each catching what the others miss.

"There's no magic bullet, but there are combinations of things that will keep building that safety net and help to reduce crashes."

-Christine Baker, Arlington County

Santa Rosa, California: Safety as the Core Organizing Principle

After Arlington showed what a Safe Systems approach looks like on the ground, the City of Santa Rosa emphasized the importance of addressing less glamorous – but immensely important – organizational practices. Dan Hennessey, Director of the Transportation and Public Works Department, Santa Rosa, explained that “Vision Zero was not going to be just another program that we added to the city's workload … What we changed was the way we make decisions. We changed who gets asked what. We changed what gets funded. We changed how projects get reviewed. We changed our standards, and importantly, we were willing to completely eliminate or redesign projects that no longer make sense."

"Safe System isn't primarily a transportation project; it's really an organizational change project." 

-Dan Hennessey, City of Santa Rosa

This organizational change is particularly prominent – and impressive – in the way Santa Rosa analyzed its Capital Improvement Program (CIP) and rewrote it to align it with a "safety by default" approach. The reframe changed the questions staff were asking, from "does this project meet current standards?" to "Is this project safe?" and "How does this project prevent death and serious injury?"

This included cutting projects that did not meet these safety minimums. Exhibit A: a major, long-planned, $60 million roadway-widening project (which was also the focus of a lawsuit). Planned to be built next to a high school and a community park, it was, upon review, a poorly conceived project. With a safety-first lens, the project was reassessed and found inconsistent with the city’s safety goals and was removed from the CIP.

“We stopped treating the CIP list as a neutral set of projects, but as a statement of values instead," Hennessey explained. Rather than having a "safety" category, the City is working to actually build safety into every program and every standard, so that every dollar becomes a safety dollar. Note that this is something many communities and plans claim – but it's rarely followed through with action and, most importantly, with dollars.

Along with rewriting its CIP, Santa Rosa also dropped level-of-service analysis as a default requirement, updated design standards, and cancelled or redesigned projects that no longer made sense. These fundamental changes go far beyond strong commitments and language in a plan and move to meaningful, life-saving action. This includes changing how the City engages the public when it comes to safety projects.

"We don't need a community to vote on whether lower impact speeds are safer. We don't need to ask whether a shorter pedestrian crossing is safer. Our job as professionals is to know what we think and engage the public on things where the input actually improves or shapes outcome in some meaningful way," Hennessey explained.

Another message from Santa Rosa regarding funding, as Hennessey encouraged: "Save yourself first" when it comes to ensuring your transportation system – plans, policies, funding decisions – are truly aligned with safety. While receiving grants is useful, of course, these are not usually improving your community's core operating systems in fundamental, lasting ways. "You don't need hundreds of people," he explained. "You need a few people willing to change the system."

Vision Zero work is hard, Hennessey reminded the audience. In the end, advancing it can't rely on popularity, outside funding, or "silver bullet" strategies. It is built on leadership, consistent effort, and a willingness to change the system. And that means digging deep to examine and, where needed, change the money, processes, standards, and decisions that shape what actually gets built.

"We could have the best Vision Zero plan in the world and still fail to produce safe streets if our internal machinery stayed the same. So we attacked that machinery."

-Dan Hennessey, City of Santa Rosa

Minnesota: Patience, data, and a 30-year story

Derek Leuer of the Minnesota Department of Transportation (MnDOT) offered a long view on the Safe System approach and some reassurance for agencies not making as much visible progress yet. "Don't feel bad if you don't have a centerline rumble strip policy ready to go right today,” he shared. “For MnDOT, this has been almost a 30-year story to get to where we got." 

Minnesota's rural two-lane highways carry a disproportionate share of the state's fatal crashes, and crossover head-on crashes are a big piece of it. Rather than assume the cause, MnDOT reviewed 251 fatal crash reports and found the biggest problems came not from drivers attempting to pass each other but from drivers drifting over the centerline or losing control. That finding focused the state's attention on centerline rumble strips, which are proven to reduce fatal head-on crashes by 44%.

Even then, the path wasn't smooth. A 2011 statewide policy triggered fierce, coordinated noise complaints, including legislative inquiries, media stories, and a moratorium. Instead of retreating, MnDOT engineered its way through, developing the quieter sinusoidal "mumble strip," which delivers the same tactile warning to drivers without the roadside noise that drew complaints. It has since drawn zero noise complaints statewide in nearly a decade, and fatal head-on crashes on the state's two-lane roads have trended down since the rollout, even as traffic volumes and vehicle sizes grew. The practice moved from a tech memo into the state's official traffic engineering manual, and then past even that:

"It's become cultural…I think these would get done even if we took it out of our traffic engineering manual, because we also have the value."

-Derek Leuer, Minnesota DOT

That's institutionalization in its truest form: a safety practice that proved itself, despite early concerns, and became standard across the state, no longer needing project-by-project review to happen.

Our Key Takeaways

Across three very different contexts, the same themes surfaced about adopting and institutionalizing a meaningful Safe System approach, including the following:

• Change the system, not just the project. The biggest gains came from changing how budgets are allocated, how projects are reviewed, and how standards align with safety, not from adding another layer of safety commitments that live in words more than action.
• Be proactive. Don't wait for a crash to reveal a risk you can already see. Use data to find and fix risky conditions before they cause harm.
• Pilot, learn, scale. Arlington's tactical speed humps and turn hardening show how small, well-measured experiments build the case for lasting change, then spread it systemwide.
• Institutionalize until safety becomes culture. Despite initial pushback, Minnesota's rumble strips became routine because the value of safety was prioritized across the agency. Instead of giving up when the first effort stumbled, safety leaders innovated to keep striving toward their safety goals.
• Use the authority you already have OR Start with what you control. The budget decisions, standards, and project-development processes your own community controls are more powerful than any outside grant, because they drive the organizational and cultural shift toward a Safe System. You don't need to convince everyone; a few committed people, backed by leadership willing to hold the line, are enough to change the system.

Read more in the Safe System Success Stories about these and other communities’ experiences working to identify and proactively address crash risks before they occur, scaling up what works, and investing in true organizational culture change to advance Vision Zero.