Reducing speed to save lives and eliminate life altering injuries is a cornerstone of Vision Zero. Unlike the traditional approach, Vision Zero brings a safe systems approach to transportation planning, priorities, and implementation. A safe systems approach recognizes that humans are going to make mistakes, and seeks to design a system that allows for these mistakes, rather than expecting perfect behavior to minimize death and injury.

Vision Zero calls on cities to manage safe speeds for everyone, whether they are driving, walking, or bicycling. Learn more about why speed matters most here. Safe speeds are especially important to help protect the most vulnerable on the road, and the difference of just 5 or 10 miles an hour can literally mean life or death in a crash.

National Study Urges Safety Over Speed & Vision Zero Approach

More than 10,000 people lose their lives each year in speeding related crashes, accounting for ⅓ of all traffic crashes across the United States. We know what works to improve safety on our roadways, but a lack of national leadership and on-the-ground action has allowed thousands more lives to be lost each year.

We commend the work of the National Transportation Safety Board, the nation’s leading authority on crashes and prevention strategies, and its landmark study, published in August 2017, for recognizing the deadly problem of speed and calling for action to dramatically reduce speed-related deaths and injuries.

The study calls the problem of speed underestimated and underappreciated, and explicitly emphasizes the need for reform of outdated practices and policies, including allowing greater local control of managing speed. Read our response to the study, which includes details on study recommendations and findings.

Effective Solutions to Slow Speeds

Three strategies are proven to be particularly effective in managing safe speeds.


Street design is one of the single-most important strategies to slow speeds and make streets safe for everyone. Design techniques like roundabouts, speed humps, medians, and road diets are all proven solutions to slowing speeds and making streets safe.

Safe street design is the foundation for a Safe Systems approach. We simply cannot educate or enforce our way out of traffic safety problems. Cities must build a foundation of streets, sidewalks, and bikeways that prioritize safety over speed.

Streets with these designs are also referred to as Complete Streets, to accommodate everyone on the road, whether they are walking, bicycling, or taking transit. The National Complete Streets Coalition has a wealth of resources on this subject and how Complete Streets can help to build complete neighborhoods.

The Federal Highway Administration (FHWA) has numerous resources on traffic calming and extensive research on traffic calming’s benefits to reduce crashes and serious injuries.

The National Association of City Transportation Officials (NACTO) has published a suite of design guides that provide excellent illustrations of design choices.


NTSB’s study recognizes that today’s standards for setting speed limits are, in many cases, outdated and ineffective.

Most states rely on the 85th percentile standard to set speed limits. This policy emerged as early as the 1940s and is based on the assumption that the majority of drivers can operate at reasonable speeds according to weather conditions, traffic, road geometry, and other factors. Yet, this viewpoint means that drivers set the speed limit.

NTSB concludes in its study that using the 85th percentile speed to set speed limits may have unintended consequences, and more specifically, that raising the speed limit to match the 85th percentile speed may lead to higher operating speeds, and hence a higher 85th percentile speed and more dangerous speeds. NTSB recommends revising traditional speed-setting standards to balance with the safe systems approach to incorporate other critical factors, such as crash history and the safety of people walking and bicycling.

Currently, speed limits on many roads are controlled by the state. If a city wants to lower the speed limit on local roads, many are forced to laboriously move state legislation to make the change. We commend cities like Portland, Seattle, New York City, and Boston — all Vision Zero cities — for working on legislative change to lower speed limits for the sake of safety.


Research shows that safety cameras, also known as automated speed enforcement, lead to long-term benefits when implemented smartly and thoughtfully. Communities that permit automated speed enforcement have experienced positive results. Data in NTSB’s report cites the review of 28 ASE studies, which collectively found that cameras reduced crashes between 8-49%.

However, because of restrictive state policies, only 14 states and Washington, D.C. currently allow for these cameras. NTSB’s study calls for states and local cities to authorize the use of automated speed enforcement because of the highly effective nature of the cameras to curb speeding.

The Insurance Institute for Highway Safety (IIHS), estimates that if all U.S. communities had speed camera programs like one in Montgomery County, MD, established in 2007, more than 22,000 fatal or incapacitating injuries would have been prevented on 25-35 mph roads nationwide in 2015.

NTSB recommends in its study that states amend laws and authorize state and local agencies to use and promote the use of automated speed enforcement.