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Process of protection

Cost, median width, traffic and death. They all come into play in the debate over when to install median barriers.

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[Times photos: Jamie Francis]
1. BUSHES: Oleander forms a botanical barrier in the Interstate 275 median and probably is a consistent barrier between Roosevelt Boulevard and 54th Avenue S. The view is from 54th Avenue N overpass.

By LEANORA MINAI, Times Staff Writer
© St. Petersburg Times
published May 10, 2002


ST. PETERSBURG -- Catrice Johnson thinks a barrier in the median of Interstate 275 would have saved her father's life.

"He probably would have hurt himself, but he probably wouldn't have died," said Johnson, 19, one of Joseph Brown's seven daughters.

Brown, 60, was behind the wheel of a northbound 14-ton dump truck that blew a recapped Bridgestone tire Tuesday, crossed the grassy median and struck a southbound van, killing himself and two Georgia men.

The stretch of interstate where Brown lost control does not have a barrier blocking vehicles from crossing over the median. Some stretches of I-275, but not all, have concrete barriers, steel guardrails or bushes in the median to help prevent vehicles from crashing into opposing traffic.

How does the Florida Department of Transportation decide where to protect motorists? Why do some stretches of highway get galvanized steel guardrails or steel-reinforced concrete barriers while other sections stay wide open? And, in the wake of Brown's crash, will a barrier go up in the median near the 26th Avenue S exit?

"If I had one accident every 10 years at that location, you probably wouldn't see any guardrail go up," said Dwayne Kile, a design engineer for the Florida Department of Transportation's Tampa district.

Two or three crashes a year, however, might warrant a review, he added.

"If I don't have any accidents, then there's really no need to expend public funds protecting people from something that doesn't occur," Kile said.

2. GUARDRAILS: This view from the pedestrian overpass at 27th Avenue N, looking north, shows a steel guardrail along the edge of the grass median.

State officials say the stretch where Brown crashed does not stand out as prone to accidents. Because of time constraints Thursday, however, state transportation officials said they could not provide accident statistics for that area of the interstate.

Johnson, Brown's daughter, is adamant: With a median barrier, she said, the dump truck would have had a better chance of staying out of the opposite lanes.

"He just would have had a bad accident," said Johnson, a St. Petersburg resident.

State highway officials say many factors play into whether a median barrier is necessary. There is no hard and fast rule.

Cost is always an issue. And in addition to the traffic volume and accident history along a portion of highway, there is the width of the median to consider. The wider the median, the more space a driver has to recover after losing control. National guidelines recommend barriers whenever a median is less than 30 feet wide.

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3. NO BARRIER: A fatal accident occurred Tuesday when a dump truck crossed this grass median on Interstate 275 and struck a van near 26th Avenue S.

However, highway safety experts are concerned that the national guidelines are outdated. The guidelines, published by the American Association of State Highway and Transportation Officials, are 25 to 30 years old.

A national study is now under way to generate better information about when and where to use median barriers.

"There's serious concern over whether it's applicable to today's highways," said Dean Sicking, director of the Midwest Roadside Safety Facility, a highway design and safety research organization at the University of Nebraska-Lincoln.

"What has happened is our cities have grown outward and as that happens, the traffic volumes in relatively rural areas have exploded," Sicking said.

The grassy median along Interstate 275 where Brown crossed over is 50 feet wide, the Florida Highway Patrol said. The national guidelines consider barriers optional when a median is 30 to 50 feet wide, and unnecessary when it's wider than 50 feet.

Florida, though, has its own stricter guidelines. The state prefers to build barriers along medians that are less than 64 feet wide. But usually that happens only with new construction or highway widening.

"There are roadways in Florida built under earlier criteria, and we haven't really made it mandatory to go back and retrofit everything," said Tom Bane, who develops median barrier standards for DOT.

Would a barrier have blocked Brown from crossing over into lanes with cars coming the other way? "There's a good probability it could have, but there's no guarantee," said Kile, the design engineer for DOT's Tampa district.

Again, it all depends.

The speed of Brown's dump truck and the angle of its impact would have had a lot to do with the outcome, Kile said.

The highway patrol said excessive speed was not a factor in Brown's crash. The speed limit in the area is 65 mph. Brown's truck was veering to the left because the left front tire blew and he lost the ability to steer the truck. As for the angle of impact, a broad swipe or glancing blow of a barrier is better than a head-on collision.

"When you hit the guardrail, it's supposed to flex enough to redirect the car so it's pointed down the road where you can stop," Kile said. "It's not there to snag you and stop you instantaneously."

Engineers also consider what type of barrier to erect. Should it be steel-reinforced concrete when a median is very narrow, such as Interstate 275 at Busch Boulevard? Or are steel guardrails enough?

Steel-reinforced concrete -- 2 feet, 8 inches high and 2 feet wide -- is the best and the most expensive barrier, engineers say. It can deflect a barreling truck better than a steel guardrail does.

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