Nashville, TN – Drivers desiring faster commutes might view a higher speed limit as helpful, but is it always the safest choice? And what about the safety needs of pedestrians, cyclists, and others?
A new study by the AAA Foundation for Traffic Safety finds that raising posted speed limits may do little to save time and increase traffic flow but could lead to more crashes, injuries, and deaths.
The AAA Foundation’s research results varied across all 12 roadway sites examined. All had new posted speed limits— six raised and six lowered— and included various road types. Click here to view the full report
Key Findings
- Raising posted speed limits was associated with increased crashes on two of three interstate highways.
- Lowering posted speed limits led to fewer crashes in many cases examined. But the likelihood of speed limit violations increased after lowering posted speed limits, suggesting the need for better public awareness education tied to these changes.
- Changes in travel times were small in response to both raised and lowered speed limits.
“Our study found no one-size-fits-all answer regarding the impact of changing speed limits,” said Megan Cooper, spokeswoman, AAA – The Auto Club Group. “AAA urges transportation officials to apply a “holistic” approach when setting or changing posted speed limits and prioritize safety over speed and capacity.”
Dangers of Speeding
Speeding is a critical factor in vehicle crashes across the nation. According to the National Highway Traffic Safety Administration (NHTSA), there were more than 42,000 traffic deaths in 2021 and again in 2022, the highest levels in 16 years. NHTSA reports that speeding was a factor in nearly 29% of the fatalities in 2021 and 27% in 2022.
AAA recommends that changes in posted speed limits should consider a range of factors, including but not limited to the type of road, surrounding land use, and historical crash data. AAA supports automated speed enforcement, but programs must be carefully implemented to maintain community support, prioritize equity and consistently drive improved safety.
“The movement in statehouses to raise speed limits is happening across the country in at least eight states this year,” said Jennifer Ryan, director of state relations for AAA. “But the benefits are overrated, and the risks are understated. Increasing speed limits does not always yield the positive results envisioned by traffic planners.”
This study is the third phase of the AAA Foundation research examining the effect of posted speed limit changes on safety. In the Foundation’s first study, traffic engineers were asked how posted speed limits are set and what factors they consider in changing them. In the second phase, crash testing revealed that small speed increases have severe and potentially deadly effects on crash outcomes.
About the AAA Foundation for Traffic Safety
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.
About AAA – The Auto Club Group
The Auto Club Group (ACG) is the second largest AAA club in North America with more than 13 million members across 14 U.S. states, the province of Quebec, and two U.S. territories.
ACG and its affiliates provide members with roadside assistance, insurance products, banking and financial services, travel offerings, and more. ACG belongs to the National AAA Federation with more than 62 million members in the United States and Canada. AAA’s mission is to protect and advance freedom of mobility and improve traffic safety.
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