The Safe System Approach: How States and Cities Are Saving Lives
|U.S. cities and States are adopting the Safe System Approach to address inequities in transportation, protect vulnerable road users, and set safer speed limits.|
Over the past decade, many States and local communities have adopted a road safety goal of zero deaths and serious injuries. At the State level, such a goal is reflected in the State’s Strategic Highway Safety Plan (SHSP) through various brandings, such as Toward Zero Deaths, Target Zero, and Destination Zero Deaths. At the local level, this goal is known as Vision Zero. The shared belief that deaths and serious injuries are unacceptable is not new. What is new is the paradigm shift in how transportation agencies are approaching safety to achieve the goal of zero deaths.
Progress is not made simply through branding and taglines. While sharing the message of a commitment to zero deaths is important, it is most useful to know what agencies have done differently from traditional practices to achieve meaningful results. What is the foundation for these successes? For many, it is the Safe System Approach.
Countries that have institutionalized the Safe System Approach since the 1990s, like Sweden and the Netherlands, have seen the fruits of their labor. According to a World Resources Institute analysis of 53 countries, those that have adopted the Safe System Approach saw at least a 50-percent reduction in fatality rates between 1994 and 2015. With this encouraging evidence, the U.S. Department of Transportation has taken the leadership role in helping to advance the Safe System Approach in States and local communities. With support from stakeholders across the public and private sector, implementing the Safe System Approach will aid in saving lives and preventing serious injuries.
“Vision Zero is not a slogan or a tagline. It’s a fundamental shift in how we approach traffic safety. It’s based on Safe System principles, starting with the ethical imperative that everyone has the right to move safely in their communities. It means using the most effective and equitable solutions to prioritize safe mobility for all.”
The following are examples of how two States and two cities committed to the goal of zero deaths by employing the Safe System Approach to address safety for all road users. These States and cities are institutionalizing the approach and using it as a foundation for the policies that affect their operations at both program and project levels.
Safe System: Washington’s Actions for All Road Users
Inspired by peer exchanges with Sweden and the Netherlands as well as Australia’s integration of Vision Zero and sustainable safety into the Safe System Approach, the Washington State Department of Transportation (WSDOT) developed its first SHSP, Target Zero, in 2000. In doing so, Washington became the first State in the Nation to set the goal of zero traffic fatalities. The multidisciplinary Safe System Approach was a natural next step in WSDOT’s progression to performance-based planning, design, and operations (practical solutions) within a multimodal system.
Early on, WSDOT focused on gaining leadership buy-in and support. Significant change initiatives often require leadership from the top to be effective. WSDOT adopted the use of executive orders to drive transformational changes. In 2013, WSDOT developed the Sustainable Highway Safety Program Executive Order. Moving Washington Forward: Practical Solutions followed in 2014 and led to changes in WSDOT engineering practices, providing significant design flexibility and including modal priority and design context in decisionmaking.
The agency also moved boldly to reorganize its structure to better define its hierarchy of responsibilities and activities. Specifically, WSDOT created an Active Transportation Division to position walking, cycling, and other human-scale active modes at the same organizational level as transit, aviation, rail, freight, and central divisions, such as traffic operations, design, and transportation safety and system analysis. The new Multimodal Development and Delivery structure became the home for these divisions, which has resulted in greater collaboration and fostered deeper cross-disciplinary understanding of safety issues, particularly for vulnerable road users. Additionally, WSDOT’s Multimodal Technical Forum supports discussions and activities across these divisions.
WSDOT’s safety policy initiatives benefit greatly from collaboration with the Washington Traffic Safety Commission (WTSC). This partnership is critical to advancing road safety because WSDOT oversees the infrastructure programing while the Commission is responsible for behavioral programing. The two agencies work together to update the SHSP Target Zero. The 2019 update included a chapter on the principles of the Safe System Approach, and the pedestrian and bicyclist safety chapter emphasized systemic engineering (e.g., narrowing lanes, road diets) and operational approaches (e,g., speed management, enhanced traffic control, and delineation for active transportation) rather than the traditional emphasis on an individual’s behavior. While the 2019 SHSP Target Zero included a section on the Safe System Approach, WSDOT and WTSC expect to highlight the principles and elements of the Safe System Approach throughout the plan in the next update. The intent is to clearly outline what the Safe System Approach entails and what is needed from Washington’s safety stakeholders, partners, and the public to achieve a Safe System.
WSDOT has now moved to integrating the Safe System Approach in practice by implementing proactive safety strategies. WSDOT has changed the safety program to de-emphasize reactive safety projects—70 percent of its safety program funding is now targeted toward crash prevention. New safety program initiatives address two core components of the Safe System Approach: reduction of crash forces and shared responsibility, which encourages engineers to design for errors. For example, WSDOT aims to reduce the kinetic energy of a crash by installing roadside safety hardware, reduce crash angles by using roundabouts, and support shorter stopping distance by applying high-friction pavements.
Setting appropriate speeds is key to the Safe System Approach, and WSDOT’s Active Transportation Division and the WTSC’s Cooper Jones Active Transportation Safety Council both provide essential leadership toward that goal. The Active Transportation Division led a multiagency working group that developed an injury minimization policy framework for speed setting based on human injury tolerance rather than the more common speed-setting methods included in the Manual on Uniform Traffic Control Devices. The principles from this approach informed a recent update to the agency’s Traffic Manual, and implementation of this policy will continue in 2022. New funding for speed management in WSDOT’s safety program is anticipated.
People walking and bicycling represent a disproportionate share of Washington State’s fatalities relative to miles traveled by mode, as WSDOT reports annually in its Gray Notebook active transportation safety report. Evaluation of crashes in Washington shows an overrepresentation of fatal and serious crashes involving active transportation within low-income communities and in communities with higher proportions of people with disabilities or who are Black, Indigenous, and people of color. These same locations often suffer from gaps in active transportation facilities. This combination results in people walking and biking, out of necessity, along roadways designed for higher speeds and traffic volumes. Future funding for active transportation projects will be determined based on a systemic analysis of roadway characteristics that prioritizes equity. A recent update to the State’s active transportation plan, available at https://wsdot.wa.gov/construction-planning/statewide-plans/active-transportation-plan, discusses these issues and provides the underlying methodology for identifying and prioritizing infrastructure gaps on State routes.
Given the importance of equity in safety, WSDOT will be incorporating “equity by design” into its implementation of the Safe System Approach. Program and project choices should result in an equitable system that factors in the context of the road and surrounding land use and demographics. Understanding needs through data analysis and evaluation will result in effective, efficient decisions and will inform modifications that do not have to sacrifice safety for mobility.
WSDOT believes in learning from others through peer exchange, knowledge transfer, research, and innovation. WSDOT wishes to play an active role in implementing the Safe System Approach and looks forward to the future. “WSDOT continues to evolve in how it plans, designs, and operates the transportation system, and advancement toward a Safe System will be key to bringing deaths and serious injuries down. Getting to a high level of implementation of the Safe System will take time, but we are committed,” says Barb Chamberlain, director of the WSDOT Active Transportation Division.
|This “self-explaining” road design for active transportation users separates different road users to avoid conflicts and improve safety.|
Using an Equity-Informed Approach in Philadelphia
Philadelphia is taking an equity-informed Safe System Approach to eliminating traffic-related deaths. The ongoing effort seeks to create safe streets and transportation options for all residents.
Philadelphia has one of the highest rates of traffic-related deaths among major American cities. In 2018, the rate of traffic-related deaths per 100,000 residents was nearly triple that of New York City, about 50 percent greater than Chicago, and almost on par with Los Angeles County, according to the National Highway Traffic Safety Administration. Philadelphians also face high rates of unemployment, poverty, and inequity.
In 2016, the city responded by adopting Vision Zero, an initiative to eliminate traffic-related deaths in Philadelphia by 2030. An action plan released in 2017 laid the groundwork for safe roadway interventions.
“The path to achieving Vision Zero is not accomplished easily and requires a fundamental and widespread commitment to systemic change from how we design our roads, to how we teach our kids to walk to school, to how we design vehicles,” said Philadelphia Mayor James F. Kenney in the Vision Zero Action Plan 2025. “It will take all of us to reach zero.”
The Vision Zero Task Force—a coalition of government officials, partner agencies, and community and advocacy groups—collaborated to introduce new transportation programs and policies that prioritize human life above all else. In these first 3 years, Philadelphia Vision Zero initiatives included 58 miles (93 kilometers) of completed safety projects, the launch of a neighborhood slow zone program, and the passage of legislation enabling an automated speed safety camera pilot on Roosevelt Boulevard, one of the deadliest roads in Philadelphia. Among the safety projects, the city built more than 10 miles (16 kilometers) of protected bike lanes, including a parking protected bike lane on Chestnut Street. Data collected before and after installation of the protected bike lane on Chestnut Street showed a 47-percent reduction in the number of vehicles driving over the speed limit during the morning commute and an 81-percent increase in people biking.
|In 2021 pedestrian median islands were installed in Philadelphia at all intersections on North Broad Street from Poplar Street to Cecil B. Moore Avenue, an intervention that has been shown have a 56-percent reduction in crashes involving pedestrians. North Broad Street is on Philadelphia’s High Injury Network; the corridor also connects several business districts and neighborhoods where a majority of residents are Black or African American. Data Sources: Pennsylvania Department of Transportation crash data (2014-2018); U.S. Census Bureau American Community Survey Data (2013-2017). Desktop Reference for Crash Reduction Factors, FHWA-SA-08-011, September 2008, Table 11.|
In 2020, Philadelphia renewed its commitment to Vision Zero with the adoption of a 5-year action plan. The Vision Zero Task Force shifted the city’s approach to a Safe System framework during a tragic year that saw an 82-percent increase in the number of Philadelphians killed in crashes compared to the previous 5-year average. Philadelphia’s Safe System Approach focuses on preventing fatal and serious injury crashes using the pillars of equity, safe speeds, safe streets, safe people, safe vehicles, and safety data. The plan is available at https://bit.ly/3qwNVEk.
By adopting the Safe System Approach, the task force aims to understand the root causes of crash risks across the entire road system and implement proactive safety solutions. One example is a partnership with researchers at the Pedestrian and Bicycle Information Center and the University of North Carolina’s Highway Safety Research Center to conduct a systemic analysis of youth pedestrian crashes to determine what types of street characteristics pose a higher crash risk. Using these results, the city can prioritize proactive interventions across the road network.
This plan also elevates the priority of slowing vehicle speeds to match roadway conditions. Automated speed safety cameras installed on Roosevelt Boulevard in 2020 sought to discourage speeding along the entire corridor. Between 2013 and 2017, 14 percent of all fatal crashes in Philadelphia occurred on this road. Cameras at eight locations on Roosevelt Boulevard captured 224,206 violations in the first month of June 2020. The Task Force and partner agencies found the number of violations dramatically decreased in the following months, resulting in a 93-percent reduction in violations by February 2021. Violations issued for vehicles traveling more than 100 miles (160 kilometers) per hour also decreased, from 75 in the first month to 7 in February 2021.This observed reduction in speeding is a significant step in the right direction to reducing risky driving behaviors, which are directly correlated with fatal and serious injury crashes.
In 2020, the Vision Zero Task Force conducted an equity analysis of the city’s high-injury network, the 12 percent of Philadelphia roads that account for 80 percent of all traffic deaths and serious injuries. The results showed fatal and serious injury crashes were three times more likely to occur in areas where most residents live on low incomes and 30 percent more likely to occur to people of color. Consequently, the plan made a commitment to focus Vision Zero efforts on low-income and minority neighborhoods.
Philadelphia continues to implement roadway interventions, including a new program known as Neighborhood Slow Zones, which focuses on traffic calming on residential streets and near schools. Construction will start in 2022 on the first two slow zones. The locations were selected through a community-driven process and then filtered through an equity and crash rate scoring system to select the first zones for implementation. Community members will collaborate with city staff to identify traffic safety issues and determine the design of the traffic calming treatments. This program seeks to go beyond single-block solutions and improve safety by addressing entire zones within historically underserved areas.
Achieving Pedestrian Safety in California
On average, approximately 3,600 people die on California’s road system annually. This represents an average of 10 deaths per day, and 3 of those are the State’s most vulnerable road users: people who bike and walk. In the United States, approximately 17 percent of traffic fatalities are pedestrians, but this number is 27 percent in California.
These alarming numbers demanded action, which the California Department of Transportation (Caltrans) undertook beginning in 2020. As Caltrans Director Toks Omishakin said in a press release, “At least two pedestrians or cyclists lose their lives on California’s transportation system each day—a number we refuse to accept or normalize. Safety remains our top priority and the department will work diligently until the trend is reversed.”
Caltrans’ work to accelerate pedestrian safety began with the introduction of a new safety paradigm. In order to establish a high-level, ongoing commitment to safety, Caltrans made a few important organizational changes to the department, including the establishment of a new Chief Safety Officer position as well as the establishment of a new Division of Safety Programs. Caltrans also incorporated four safety-focused pillars into its 2020–2024 SHSP as well as the 2020–2024 Caltrans Strategic Plan. One of these pillars is to implement the Safe System Approach. The 2021 California State Transportation Agency’s Climate Action Plan for Transportation Infrastructure details how the State recommends investing billions of discretionary transportation dollars annually to aggressively combat and adapt to climate change while supporting public health, safety, and equity, and explicitly commits to the Safe System Approach.
The institutional commitment to the Safe System Approach enabled Caltrans’ Pedestrian Safety Improvement Monitoring Pilot Program, which had been piloted in 2016, to receive further funding and resources. This pilot identified and investigated pedestrian-related high collision concentration locations and was made permanent in July 2020. In addition, in September 2020, Caltrans introduced a new Pedestrian Systemic Safety Improvement Program that addresses serious pedestrian injuries and fatalities before they occur through a combination of crash modeling, statistical analysis, and risk analysis. The program integrates Safe System elements and principles into a systemic approach to emphasize that safety is proactive and to further the goal of zero deaths.
Caltrans’ two pedestrian safety improvement programs (Pedestrian Safety Improvement Monitoring Program and Pedestrian Systemic Safety Improvement Program) complement each other. While the Pedestrian Safety Improvement Monitoring Program’s approach is reactive in the sense that it focuses on locations that have a history of crashes, the Pedestrian Systemic Safety Improvement Program embodies many principles and elements of the Safe System Approach. The Pedestrian Systemic Safety Improvement Program advances the belief that safety must be proactive—it uses crash data to identify roadways that suffer from recurring safety challenges, but it is also proactive because it provides a mechanism to make improvements at sites that, while they share the same design and operational attributes, have not experienced many, or any, crashes. Both the data-driven and proactive approaches are needed to support pedestrian safety improvements throughout the State highway system.
To develop the Pedestrian Systemic Safety Improvement Program, Caltrans safety staff first gathered and compiled crash data. Then, they teamed up with researchers from the Safe Transportation Research and Education Center at the University of California–Berkeley to develop a pedestrian-specific systemic safety model. The model identifies systemic “hot spots,” or locations that are at high risk for future crashes. These hot spot locations are proactively selected not only based on locations where crashes have occurred but also on their specific features, context, and characteristics—providing a comprehensive, systemic view.
Once the team identified the systemic list, they applied a prioritization process to sort the locations for the most pressing intervention need. This prioritization process was based on multiple variables, including collision rate, pedestrian volume exposure, equity as measured by disadvantaged communities, senior and youth population density, and school proximity. This analysis enabled Caltrans to make the most informed decisions about where California should invest its resources to maximize pedestrian safety benefits.
Last, traffic safety investigators implemented pedestrian safety countermeasures at the selected locations. To accomplish this, they relied on the Pedestrian Safety Countermeasures Toolbox and a companion training course developed by Caltrans. This toolbox, which includes 47 countermeasures, helps investigators select the most appropriate safety countermeasure for each unique location.
|The cover of the Caltrans publication Pedestrian Safety Countermeasures Toolbox.|
As an outcome, in its first year, the Pedestrian Systemic Safety Improvement Program identified more than 500 locations for investigation and improvements. Caltrans is already implementing pedestrian safety measures at target locations, and the Pedestrian Systemic Safety Improvement Program is currently in its second round. The success of the pedestrian program has laid the foundation for the establishment of additional systemic safety programs based on the Safe System Approach.
Other Caltrans safety efforts include establishing policies and standards on proven safety countermeasures, developing local traffic safety plans for each of the 12 Caltrans districts in California, and implementing the results of a research project titled Developing a Safe System Approach to Setting Speed Limits, which is currently underway. In addition, Caltrans will partner with the California Office of Traffic Safety, which is providing more than $8 million in funding for programs implementing safe and equal access to roads for pedestrians. Finally, the California Transportation Commission recently approved $100 million for projects dedicated to pedestrian-focused infrastructure improvements.
Setting Safe Speed Limits in Portland
Everyone deserves to reach their destinations safely. Safe driving speeds reduce the number and severity of crashes. Slower-
moving drivers can stop more quickly to avoid a crash and, when a collision does occur, lower speeds reduce the chance of injury or death.
The city of Portland, OR, is actively managing driving speeds with a four-pronged Safe System Approach: lowering posted speed limits to support safe multimodal travel, redesigning streets, educating drivers, and enforcing speed limits with speed safety cameras. A notable success is Portland’s 5-year transition to setting speed limits based on the Safe System Approach.
Oregon sets speed limits on all streets in the State, regardless of street ownership. Speed limits on roads in Oregon have traditionally been established with an engineering approach that relies heavily on street classification and existing driving speeds, especially the 85th percentile speed (the speed at which 85 percent of drivers are traveling at or below during free flow conditions). This approach typically does not adequately consider vulnerable road users, land uses, or existing infrastructure when determining the posted speed limit.
Portland committed to Vision Zero in 2015, and yet struggled to reduce speed limits on its streets, in part because of State control of speed limit setting, including a speed limit request process that did not consider urban context and a lengthy review time. To address those barriers, the Portland Bureau of Transportation (PBOT) has worked with the Oregon Department of Transportation (ODOT) and other jurisdictions to develop, test, and eventually adopt a speed limit setting process statewide that is proximate to the Safe System Approach, which recommends identifying the safest speed for all road users and then building infrastructure to support that speed.
In 2016, PBOT developed an alternative speed-setting methodology that ODOT agreed to pilot on nonarterial streets in Portland. The alternative methodology identifies appropriate speed limits based primarily on street design and associated crash risk factors for people walking, biking, and driving, such as the presence and quality of bike lanes, sidewalks, and median separators.
The alternative methodology enabled Portland to move quickly in requesting that speed limits be reduced on 46 miles (76 kilometers) of collector streets from 2016 to 2020. The alternative methodology is also simpler, which led to faster ODOT response times (average of 2 months instead of 7 months). However, most of Portland’s 30 High Crash Network streets are functionally classified as arterials, and therefore they were not eligible for the alternative speed-setting method, which significantly limited Portland’s effort to set safe speed limits on its most deadly streets. Despite this limitation, piloting the alternative methodology built understanding and was an important step in transitioning to the Safe System Approach.
In 2019, ODOT convened a roundtable to address speed setting with participation from cities and counties across Oregon. The event took place as PBOT was advocating for the Safe System Approach to speed setting locally, and national and international guidance was emerging with similar recommendations.
Following the roundtable’s recommendations, in 2020, ODOT adopted a new statewide speed setting approach for all street classifications, including arterial streets. The new methodology within city limits primarily relies on context (land use density, nonmotorized activity, and infrastructure), 50th percentile speeds instead of 85th percentile, and setting allowable speed ranges for different land uses and street classifications.
Portland is taking two next steps to advance the Safe System Approach to speed limit setting. First, PBOT is developing comprehensive guidance for speed limit setting for Portland that will identify safe speed limits based on context and human vulnerability. Second, PBOT is working with ODOT to shape guidelines for new statewide legislation that gives Portland and other eligible cities authority to set speed limits as long as State guidelines are followed.
“The 5-year process that Portland has undertaken to transition from a traditional approach to speed limit setting to the Safe System Approach can help provide guidance to other jurisdictions,” says PBOT City Traffic Engineer Wendy Cawley. “Setting a vision, collaborating with partners, taking incremental steps, and centering a methodology on the protection of human life are core elements in the process.”
|The alternative speed setting methodology that ODOT and PBOT piloted relies primarily on street design and crash risk factors for people walking, biking, and driving, compared to the traditional methodology that set speed limits based largely on the speeds people drive during free-flow conditions.|
Providing Valuable Insight
The Safe System Approach offers the necessary strategies for saving lives and helping to eliminate deaths and serious injuries on the Nation’s roadways. Tribal, local, regional, State, and Federal organizations have begun to integrate the approach in their safety programs and projects, and soon will expand the approach beyond the safety disciplines. Examples of successful programs from these organizations can provide valuable insights for others who are planning to advance the approach.
Chimai Ngo is a program manager for zero deaths, safety culture, and transportation safety planning initiatives in the Federal Highway Administration’s Office of Safety. She holds a master’s degree in planning from the University of Virginia.
John Milton, Ph.D., P.E., is the State safety engineer for WSDOT, with 33 years of experience in multimodal safety. He is the chair of the Transportation Research Board’s Safety Section, chair of the World Road Association Technical Committee on Road Safety, and vice chair for the Committee on Safety for the American Association of State Highway and Transportation Officials. He holds a doctorate from the University of Washington.
Lily Reynolds, AICP, is an urban planner specializing in streets, sidewalks, community engagement, and project management. She has extensive experience working with diverse partners to build consensus around complex transportation projects. Currently she is the deputy director of complete streets in the Office of Transportation, Infrastructure, and Sustainability in Philadelphia. Lily holds a master’s degree in urban studies from the Simon Fraser University, Canada, and a bachelor of arts in geography from the University of British Columbia, Canada.
Rachel Carpenter, P.E., was appointed the California Department of Transportation’s first-ever chief safety officer effective January 2020. She is Caltrans’ highest-level subject matter expert on safety and manages the day-to-day operations of the newly established Division of Safety Programs. She holds B.S. and M.S. degrees in civil engineering from Cal Poly, San Luis Obispo and University of California Davis.
Clay Veka is the Vision Zero coordinator at PBOT in Oregon. She has worked in traffic safety for almost 15 years and has her master’s degree in urban design and planning from the University of Washington.
The authors would like to thank Barb Chamberlain at WSDOT; Elizabeth Dobbins at the Philadelphia Office of Transportation, Infrastructure, and Sustainability; Jessica Downing at Caltrans; and Matt Kelly at PBOT for their contributions to this article.
For more information, contact Chimai Ngo at firstname.lastname@example.org.