The research is clear, increased driver speeds lead to more dangerous roads. For example, increasing the state maximum speed limit by 5 mph results in an 8% increase in the fatality rate on interstates and freeways, and a 4% increase on other roads. Speed is even more dangerous for pedestrians; research shows that a person hit by a car traveling at 35 mph is five times more likely to die than a person hit by a car traveling at 20 mph. These facts highlight the important role speed limits play in creating safe streets, and is one of the reasons the Colorado DOT (CDOT) is rethinking how it determines appropriate limits.
speed limit
State DOTs are helping locals set lower speed limits
In response to mounting safety issues, more transportation agencies are recognizing the importance of managing traffic speeds—a shift from long-held practices that prioritize vehicle speed. In the long run, this will require widespread changes in road design that reinforce lower travel speeds through physical and visual cues. Until then, however, authorities are turning to more immediate strategies like setting lower speed limits in urbanized areas. As the leading authorities across much of the U.S., state DOTs are stepping up to the task.
Speed limit standards are an essential step toward safer streets
New considerations for setting speed limits have the potential to shift the practice away from the historic norm of service to drivers, and toward the safety and accommodation of all users.
Safety and speed management: Speeding into a crash?
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.
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.
In Ohio, speed limits go up—and with them crashes, injuries, and deaths
Like many other local, state, and federal transportation agencies, the Ohio DOT has a zero crash death goal. However, a 2013 law to raise speed limits on nearly 1,000 centerline miles is making that goal harder to reach, according to a recent study by the state Department of Public Safety.
Study of variable speed limits highlights the trade-off of throughput and safety
Varying a posted speed limit based on current conditions can improve operations and safety in congested work zones, a team from Missouri found. This study from the University of Missouri-Columbus explores this phenomenon in a congested work zone in St. Louis, Missouri. The findings? Results depend on whether DOTs are looking to prioritize safety over capacity.
Researchers explore links between speed and safety
As states experiment with increasing and lowering speed limits on rural highways, questions still remain as to what effects those changes might have on safety. At this year’s annual meeting of the Transportation Research Board, researchers trying to answer some of those questions found that slower is safer.
Vision Zero spreads across the U.S.
In 1997, Sweden undertook a road safety project with an ambitious goal: No traffic fatalities or serious injuries. A core principle of Vision Zero was that, “Life and health can never be exchanged for other benefits within the society.” Now the goal of zero traffic deaths is spreading in the U.S., principally in cities, but some states have also adopted Vision Zero plans.