FRANKLIN, Tenn. - Traffic was backed up for miles on Interstate 65 southbound lane after an exit sign tumbled onto the highway.

Parts of the signs were removed off the interstate before afternoon rush hour traffic.

The sign advertised the Cool Springs Boulevard exit or exit 68B.

"We were just going and thought it was smooth sailing, and all of a sudden we saw people just slowing down," said a motorist.

"You don't think a light is going to fall on you, or a sign is going to drop on you, or anything," said a motorist.

The cantilever sign fell 11:30 a.m. near Cool Springs Boulevard, which leads to CoolSprings Galleria, a local mall.

The 15,000-pound sign did not hit any vehicles.

Tennessee Department of Transportation officials said worn metal contributed to the fall.

"I was right here in the parking lot, and I heard this thing snap. It was a loud popping sound, and then the crash, and a lot of cars screeching and swerving and I looked up and that had fallen over," said Mark Myers, an eyewitness who works as a security guard.

Even TDOT officials are scratching their heads. Could metal fatigue be to blame?

"We have had some issues with the bolts, the sign structure. We've had some issues with the bolts breaking, but never a failure of this nature that caused it just to completely collapse on the roadway," said TDOT spokeswoman BJ Doughty.

"We'll be taking a close look at not just this sign, but we'll be looking at all the cantilever signs we have all over the state," she said.

The sign didn't crash on anyone, but it caused a chain reaction crash that sent four people to the hospital.

"There's nothing you can do, it is just one of those freak accidents that is not supposed to happen," said a motorist.

The sign was installed 15 years ago. The last time it was inspected was in 2000, with some follow-up maintenance in 2002.

TDOT said it is following federal guidelines in taking care of the exit signs.

The four people taken to the hospital included two children; the adults suffered minor injuries.

I'm glad no one was killed. That thing would chop a car in half.

I know. Every time I drive under one of those things I think "what if?" That's just freaky.

That's what I think when I cross a bridge, especially after last year.

Strangely, that's actually never come to mind, but after reading this story, I'll be reminded of this. I'm glad that no one was injured.

^ I know. Luckily this was lunch time and not rush hour. During rush hour, traffic on this stretch of road is bumper to bumper for miles, and the speed is only about 40-45 mph. In fact, this exit during rush hour has traffic just sitting there. This could've been so much worse.

that sign chopped into the road!

omg that could have been fatal to anyone
glad no one got hurt

I don't think I want to drive for awhile...