September 1, 2006
States go global for road-safety ideas
By John Gramlich, Staff Writer
Photo courtesy of the Minnesota Department of Public SafetyOn Minnesota's state Highway 55, white dots painted on the road encourage drivers to keep safe following distances. The idea originated in England, according to transportation officials.
Low-cost devices increasingly popping up on treacherous roadways and crammed crossroads across the nation have been used in foreign countries for years.
White, oval-shaped dots painted on roads in Minnesota, Pennsylvania and Washington state to prevent drivers from tailgating - and a similar system using hot-pink markers on the Chesapeake Bay Bridge in Maryland - have British roots. (See related story: State DOTs hope drivers see dots )
An improvement on highway barriers made of flexible cables that soften crash impacts while eliminating crossover collisions has caught on in a handful of states and also derives from the United Kingdom.
And new designs for intersections in Missouri and Utah seeking to reduce delays and dangers associated with making left turns are based on efforts in France and Mexico.
States regularly pick up on road-safety plans developed overseas and the imported ideas often spread from state to state, said Harold Linnenkohl, president of the American Association of State Highway and Transportation Officials (AASHTO).
"We may think we're smart, but we don't have all the ideas," said Linnenkohl, who also serves as commissioner of the Georgia Department of Transportation. "We can learn from each other. The only way we're going to address our needs is by sharing."
On Aug. 11, Washington became the fourth state, along with Maryland and Minnesota this summer and Pennsylvania earlier, to introduce a version of a British anti-tailgating program in the United States.
Washington officials painted white dots on a two-mile stretch of Interstate 5 known for tailgating near Nisqually, about 50 miles southwest of Seattle, and posted signs urging drivers to keep a minimum two dots - or the equivalent of two seconds - apart.
But the state Department of Transportation pulled the plug on the program after only three days. Confused motorists slowed down to read the signs, causing seven-mile backups during the project's first weekend, according to state transportation spokeswoman Lisa Murdock.
"We still believe in the program. We think it works," Murdock said. "We just need to find a better location."
Despite the rough start in Washington, the dots are working in other states, according to transportation officials.
Pennsylvania, which unveiled the plan stateside in 2000, has seen a marked decline in accidents on one stretch of highway featuring the dots. On Minnesota's lone road using the dots, "following distances have increased, which is a good thing," said state Department of Public Safety spokesman Gordy Pehrson.
One reason for the popularity of the dots is their price: installing one test site, including equipment, signs and labor, costs less than $2,000, according to a Federal Highway Administration (FHWA) estimate.
Meanwhile, another low-cost road safety device - highway barriers made of metal cables - has become common across much of the nation. While New York first used low-tension cable barriers as early as the 1960s, a British firm developed more popular, high-tension dividers, according to the FHWA.
High-tension cables require less maintenance than low-tension barriers because they are more likely to stay intact after a collision, experts say.
Like concrete "Jersey walls" often used along median strips or road construction zones, cable barriers prevent vehicles from crossing lanes into oncoming traffic, but for roughly half the price. Transportation experts say the cables also provide more cushioning than concrete barriers, increasing the likelihood that drivers will survive crashes. Officials nationwide have hailed the idea.
In Utah, high-tension cables have been a "tremendous success," with no crossover fatalities in any of the locations where they have been installed, according to Nile Easton of the state Department of Transportation. Twelve people in two years died in crossover collisions on the same roads before the cables were installed, Easton said.
Illinois, Indiana, Ohio and Washington are among a number of states expanding their use of the high-tension cable barriers.
Wisconsin Gov. Jim Doyle (D) on July 25 ordered the state Department of Transportation to install low-tension cable barriers on a stretch of Interstate 43 about 20 miles north of Milwaukee after six people died in recent crossover accidents there. In North Carolina, most of the state's highways now use the low-tension technology, which is cheaper to install.
To gather best practices from other countries, the state highway and transportation officials' association and the FHWA organize international "scanning programs" that allow state officials to travel abroad and meet their foreign counterparts.
Easton said a trip to Mexico gave Utah officials the idea for a "continuous flow intersection" being planned in West Valley City, about eight miles west of Salt Lake City.
The redesigned intersection will divert those turning left into a new far left-hand turn lane before they reach the intersection. Drivers then turn without crossing oncoming traffic.
The plan, significantly cheaper than building a highway interchange, reduces the risk of turn-related collisions and speeds up traffic cycles, according to Easton. And drivers will be able to understand the new intersection immediately, he said.
"It actually becomes very intuitive when you drive through it," he said.
Missouri, meanwhile, is using a similar plan for the country's first "diverging diamond interchange" in Kansas City, based on an existing model near Versailles, France, according to the FHWA. Concrete medians also will direct traffic into a new lane to facilitate left turns.