Risky Speeding Behaviors

Raising speed limits on highways could lead to more crashes on nearby roads, according to new research by the AAA Foundation for Traffic Safety. This "spillover effect" creates unintended safety hazards for local communities that might not be involved in the decision-making process to raise the posted speed limit on a nearby highway.  According to NHTSA, speeding is a significant safety concern, contributing to almost one-third of road fatalities in the past 20 years. 

AAA Foundation researchers investigated whether changes to posted speed limits on interstate highways could cause drivers to adopt risky speeding behaviors on local streets. The study looked at crash data before and after speed limit increases on interstates in Georgia, Michigan, and Oregon. Hot spot analyses were conducted on roads within a 1-mile radius of interstates. Researchers found many instances where speed-related crashes increased on nearby roads following the interstate speed limit change, suggesting that drivers exiting the highway continued their faster tendencies.

“While raising the posted speed limits could seemingly oil the wheels of traffic flow, it may birth unforeseen repercussions in local communities,” said Montrae Waiters, spokeswoman, AAA – The Auto Club Group. “For one thing, higher speeds could result in more severe traffic crashes. Additionally, this new research demonstrates that drivers will be moving faster when transitioning onto local streets, which are designed for slower speeds and diverse road users such as pedestrians and cyclists—not for speeding drivers."

AAA recommends a multi-pronged approach to combat speeding behavior:

Education

·       Public awareness campaigns focused on the riskiest drivers.

Technology

·       Equitably placed automated speed enforcement and screening tools.

Road Design

·       Narrower lanes, speed humps, roadway landscaping, and curb extensions.

By taking a proactive approach, transportation officials can create safer road networks for all communities. The AAA Foundation’s research reinforces the importance of the Safe System Approach (SSA). The SSA is a strategic way of leveraging the engineering and behavioral countermeasures proven effective at preventing traffic crashes and the injuries that can result from them. Explore the Foundation’s guide for implementing the SSA in your community HERE.

"This research has uncovered a potentially lethal consequence of raising highway speed limits," said Jake Nelson, AAA’s director of traffic safety advocacy. "With the U.S. near a record-high traffic death toll, road authorities can use these findings and an effective tool to pinpoint lifesaving solutions to help ensure that we all get home safely each day."

Previous speeding research by the AAA Foundation found that raising posted highway speed limits is associated with increased crash frequencies in some situations. At the same time, changes in travel times were small in response to both raised and lowered speed limits.

About the AAA Foundation

Established in 1947 by AAA, the Foundation for Traffic Safety is a nonprofit, publicly funded 501(c)(3) charitable research and educational organization. The AAA Foundation’s mission is to prevent traffic deaths and injuries by researching their causes and by educating the public about strategies to prevent crashes and reduce injuries when they do occur. This research informs the development of educational materials for drivers, pedestrians, bicyclists, and other road users.