In the past eight years, three men have died after smashing into the barrier wall of Interstate 375, an elevated 1.2-mile route that veers off toward downtown.
A motorcyclist hurtled over the wall in 2001. Two years ago a diesel tanker slammed into the wall and sparked a 30-foot-high explosion that rained burning fuel. This week, a 23-year-old driver lost control and plummeted 45 feet to his death.
The state blames speed and distractions. But commuters and safety advocates suggest the exit's design emphasized cost over safety. They call it outdated and unsafe.
"This is an incredibly dumb design. And everybody knows it," said Gerald Donaldson, senior research director for the nonprofit Advocates for Highway and Auto Safety. "But they did it to save money, they did it to save concrete, they did it to save time."
He said the ramp is a rarity in highway design, an upward-swooping left-side exit with 2-foot-9-inch barriers.
The left exit is counterintuitive, forcing drivers to slow down in the fast lane. The road's elevation occludes a clear view of what lies around the corner. And the short, angled barrier walls do little to keep vehicles on the road, he said.
State officials disagree. About 23,000 people use the interchange daily, according to 2007 figures, and the only fatal accidents were caused by motorists' mistakes that designers could not predict, said Britton Hardy, district roadway engineer for the state Department of Transportation.
"It's basically not an issue," Hardy said. "If it were a problem, we would have to figure out some way to solve it."
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The $3 million "North Bay Drive,'' as it was called, opened in 1978 and immediately turned heads because of its size and height.
Patients at the former St. Petersburg Osteopathic Hospital, a facility whose rooftop sat 15 feet away from the roadway, requested rooms away from the constant rumble of the road, a Times story said that year.
Little has changed with the exit in more than 30 years, save the monthlong closure and reconstruction after the tanker inferno.
"The motor vehicle fleet changes, people change, but the built interstate system is glacial," Donaldson said. With higher speed limits, bigger vehicles and more highway research, designs like I-375 have become outdated, he said.
DOT officials have no problem with the design. They say left-hand exits are used nationwide and are not uncommon on local highways.
Not everybody agrees.
"Left-hand lanes are always more complicated for people, just in terms of handling them or getting to them," said Joan Claybrook, a former head of the National Highway Traffic Safety Administration.
Doug Hecox, spokesman for the Federal Highway Administration, said left-hand exits are not as common but often necessary when space and finances are tight.
Of the 53 exits on I-275, only three — 31st Street South, I-175 and I-375 — are on the left, according to FDOT district manager Kevin Dunn.
Engineers gradually are embracing the ''jughandle left'' design, which creates a staging area that clearly separates the left exit lane, eliminating any possible surprise.
DOT officials aren't interested.
"People make that ramp everyday and have no issues," said spokeswoman Kris Carson. "If you're going the legal speed limit then it shouldn't be a problem."
FHP records indicate that, besides the three deadly accidents, troopers have responded to about half a dozen crashes along the ramp since 2003. Two St. Petersburg motorists, Darrell Scott, 22, and Pamela Butler, 17, died on the ramp three years after its opening.
The accidents show design is as important as driver ingenuity, Donaldson said.
"You never surprise them,'' he said. "And having a left-hand exit is an inherent surprise."
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Surprise is what makes the exit's barrier wall so dangerous, some motorists say.
The speed drops quickly from 65 mph to 50 mph. Then motorists are confronted with a more than 90-degree turn, bordered by a 2-foot-9-inch barrier wall.
"When you're so high up there you should have some better protection," said Edward Ringwald, a city employee who drives the exit every day. "If you've not slowed down in time, you'll end up going off that ramp."
The walls, known as "New Jersey barriers," have been a national roadway standard for decades, said the DOT's Hardy.
Developed in the 1950s, the barriers were never formally crash tested. But actual road experience indicated the walls were capable of redirecting a semitrailer truck at 60 mph, he said.
The protection hasn't changed much since because roadway engineers "haven't found a reason to change it," said Hardy.
On this point, federal highway official Hecox agrees.
"Their job is to bring a vehicle to a stop. More times than not, they work," he said.
But Donaldson suggested the current wall height is impractical. Given the varying centers of gravity of all road vehicles, barriers should measure 54 inches tall — nearly 2 feet taller than I-375's walls, he said.
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In all three fatal accidents, safety advocates and DOT officials agree, several factors were involved.
In the 2001 crash, investigators believe Barry John Roberts II, 20, of St. Petersburg, was driving his sport motorcycle at 80 mph.
Truck driver Ronald Kennedy, 47, of Zephyrhills, confused the exit with the highway seconds before his diesel tanker exploded. He was killed in the crash.
And preliminary reports from the Florida Highway Patrol estimate Leonardo Llana, 23, of Clearwater, was speeding more than 93 mph around the corner when he crashed this week.
Neither Roberts nor Kennedy had been drinking. The FHP has yet to say whether Llana had been drinking.
All three accidents occurred after sundown.
Ringwald said low lighting and inadequate signage on the exit may have contributed to its danger.
"Unsafe. Very unsafe," Ringwald said. The DOT is "skimping on signs there instead of protecting the public."
Hardy said two overhead signs and yellow "LEFT" placards notify drivers of the exit beforehand. Two streetlights, a high-mast lamp and barrier reflectors illuminate the road at night.
Visibility concerns aside, exits like I-375 are dangerous, said Donaldson, The few tragedies are more a testament to drivers' reactions than highway design, he said.
"This isn't just an issue of making a smooth travel surface," Donaldson said. "It's a public health issue. And (engineers) have public health responsibilities."
Times researcher Mary Mellstrom contributed to this report. Drew Harwell can be reached at firstname.lastname@example.org or (813) 226-3386.