According to a recent study conducted by the Insurance Institute for Highway Safety (IIHS), in the past 25 years 37,000 additional people have died due to increased speed limits in the United States. Meanwhile, Canada is taking a very different approach to speed, as detailed in the April issue of ITE Journal, which is dedicated to safety through speed management.
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NTSB priority: Roadway speed management
When it comes to speed, delay and congestion usually get more attention than the flip-side problem of excessive speed. Under statute, for example, the federal government requires agencies to track speed reliability and delay. There is no similar requirement for tracking excessive speed, even though the data set provided for monitoring slow traffic could be used for fast traffic as well. However, the National Transportation Safety Board’s new 2019-2020 Most Wanted List, which it identifies as its “premier advocacy tool” in advancing transportation safety improvements, includes highway speed management in its Top 10 list.
Speeding contributes to one-quarter of fatalities, but remains culturally acceptable
As a vehicle’s speed increases, it’s kinetic energy increases exponentially. A small amount of speed reduction can translate into a big reduction of kinetic energy, and reduces the potential severity of a crash. A new report from the Governors Highway Safety Association (GHSA) takes a comprehensive look at speeding on American roadways, including observations about who is speeding, why they are speeding, and what can be done to reduce it.
Variable speed limits effective along Virginia’s foggy highways
Fog can create deadly driving conditions, particularly in mountainous areas. Fog along the 12-mile stretch of highway in Virginia has led to hundreds of crashed vehicles and several deaths over the last couple of decades. In 2016, VDOT launched a system of weather sensors, variable speed limits (VSLs), and dynamic message signs (DMS) meant to slow down drivers during unsafe conditions. This system lowered speeds by an additional 2 to 5 mph, on average, and the number of fog-related crashes seems to have dropped by more than 50 percent. VDOT will continue to monitor the corridor, but the Virginia Transportation Research Council says similar systems should be effective for more widespread use.
85th percentile speed limits: “Fast, Furious & Fatal”
A study by UCLA examines the use of the 85th percentile to set speed limits, including a California law that gives little flexibility to local jurisdictions. The principal author argues that the 85th percentile is not a good standard of safety. She cites an “injury minimization” scheme, and recommends that local governments be freed from the current standard in order to pursue these safer limits.
Lowering speed limits can reduce crashes
Speed limits are often based on observed 85th percentile free flow speeds. Setting them lower, even to address safety concerns, can be difficult once engineering recommendations have been made. A new study, however, bolsters the case for doing so by showing that setting limits just below the observed speeds can reduce crashes, including the most serious ones.
Lowering speed limits can reduce crashes
Speed limits are often based on observed 85th percentile free flow speeds. Setting them lower, even to address safety concerns, can be difficult once engineering recommendations have been made. A new study, however, bolsters the case for doing so by showing that setting limits just below the observed speeds can reduce crashes, including the most serious ones.
Toward livable streets: A review of recent improvements in practice
In the last decade a number of project development and design guides, such as ITE’s “Designing Walkable Urban Thoroughfares,” NACTO’s “Urban Street Design Guide,” and city design guide manuals, have emerged. A new article by Eric Dumbaugh of Florida Atlantic University and Michael King of BuroHappold Engineering, reviews these updated practices. The article finds four general principles of livable streets engineering.
Speeding is akin to an addiction, and roadway design can be an effective treatment
Gerry Forbes, author of the Transportation Association of Canada’s excellent and too-little-known “Speed Management Guide,” suggests in a new ITE Journal article that speeding has some attributes of an addiction. He compares speeding and several addictive substances on dependence and harm, suggesting speeding is right up there with cocaine and heroin. Probably more interesting than this provocative framing is the remedy Forbes suggests. He rejects the idea that speed management is simply a matter for law enforcement.
International review confirms speed management is critical to road safety
Speed reductions can lower crash risks significantly, confirms a new report by the International Transport Forum, an intergovernmental organization of 59 member countries including the U.S. The research report looks at 11 case studies in 10 different countries around the world. In every case, speed increases were associated with more crashes and more severe injuries, while speed decreases were associated with fewer crashes, injuries, and deaths. The relationships, however, are not linear.