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The AAA Foundation for Traffic Safety has been examining topics related to posted speed limits and speeding since 2017 and has published several documents thus far that described practices for setting posted speed limits in the U.S.; the impact of speed increases on driver safety from vehicle crash tests; and traffic fatalities in relation to […]
Speeding is a significant safety concern and has contributed to almost one-third of road fatalities in the past 20 years. This research investigated whether changing to higher posted speed limits on Interstates can cause spillover effects, or a systemic propagation of speeding behaviors that results in more crashes at nearby road segments. Findings presented in […]
Speed is a contributor to both crash frequency and crash severity. This project explored efforts to reduce speed and evaluated their effectiveness in improving safety for pedestrians and bicyclists. Phase 1 was a program scan that identified countermeasures in use throughout the United States. Based on the scan, the team evaluated automated speed enforcement and […]
This study examined the effects of posted speed limit changes on traffic safety by conducting before-and-after assessments using crash and speed data from multiple sites. Despite numerous studies reporting the negative impacts of increased speeds on traffic safety, many states have raised their posted speed limits. In response, the AAA Foundation for Traffic Safety (AAA […]
In 2020, there were 11,258 people killed in speeding-related crashes, accounting for 29% of all fatal crashes in the United States. Additionally, 87% of all speeding-related traffic fatalities on American roads occurred on non-interstate roadways. To help reduce the number of speeding fatalities on the roads, NHTSA has developed a new 2022 safety campaign to […]
The “85th percentile rule” is commonly used to set speed limits in jurisdictions across the U.S. Modern interpretations of the rule are that it satisfies key conditions needed for safe roadways: it sets speed limits deemed reasonable to the typical, prudent driver, reduces the problematic variance in travel speeds among vehicles, and allows law enforcement […]
A systematic and ongoing method of measuring vehicle speeds was introduced in South Australia in 2007 in order to assess the effects of speed reduction countermeasures and to monitor the speed behavior of South Australian motorists over time. More than 100 sites around South Australia have speed measurements taken for a one week period at […]
