Interstate 75 stretches 1,787 miles from Miami to Sault Ste. Marie, Mich., on the Canadian border. But in few places is it more scenic than in the rolling countryside of southern Tennessee—or more deadly. There, where the route follows the Tennessee River valley, blinding fogs had led to mass collisions four times in the past 16 years. But none equaled the calamity at about 9:30 AM on Dec. 11. A sudden, impenetrable fog became a shroud for 12 travelers who were killed as 83 vehicles piled up, leaving more than 50 other people injured. The toll could have been worse had it not been for the extraordinary bravery of ordinary people. One woman in particular, Chattanooga housewife Bonnie Whaley, is credited by numerous witnesses with saving lives by running up the highway to warn off oncoming traffic.

Low-visibility pileups are a constant threat: Just last week, dozens of cars were involved in a fatal collision in Utah. Correspondent Gail Wescott spoke to Whaley and other survivors of the 1-75 disaster about their ordeal in the fog.

ALLEN RODGERS, 39, an engineering consultant for AT&T, set out that morning from Woodstock, Ga., bound for a job in Athens, Term., with two colleagues, Dave Clark and Brent Shaw, both 33.

RODGERS: I was driving my '86 Mercury Topaz. It's silver, the exact same color as fog. I think it was just beyond Cleveland [Tenn.] that I noticed signs that said DENSE FOG NEXT 5 MILES. From a rise we could see huge black smoke and some white smoke coming up from [what looked like] low clouds.

CLARK: It looked like a mushroom cloud.

RODGERS: I said, "Well, I guess we're coming up on a nuclear holocaust." I was joking around. Suddenly we were in the fog. Very quickly, it was so thick that you couldn't see 10 to 20 feet.

CLARK: Then out of nowhere I saw this lady waving her arms up and down, and I said, "What is she doing?"

RODGERS: Everything started happening very fast. I saw this black man on my left. He had a stick with a T-shirt or something tied around it, and he sort of lunged out at us. And out of the other corner of my eye I saw this woman standing on the edge of the pavement screaming and waving her arms up and down, going, "SLOW DOWN! SLOW DOWN!" We were right where a lane pulls away to go up an exit ramp, and in that little triangle where it's just gravel and dirt, I saw this black man just crawling. We saw him stand up, fall down; his face was all bloody. Dave jumped out to help the guy. I managed to pull up in front of a truck stopped on the ramp, and I parked and got out. It was like stepping into a nightmare. [They were at about the midpoint of the three-quarter-mile string of crashes.] I could see right away how close we had come to wrecking. If it hadn't been for that woman, we would have' been next.

BONNIE WHALEY, 48, was driving her '89 Nissan from Chattanooga to Knoxville to visit her brother-in-law: It was a real pretty day when I left the house. I wasn't even thinking about fog because it was sunny and very clear. I had just crossed the Hi-wassee Bridge when a highway patrol trooper passed me. And then I couldn't believe it; he just disappeared, just totally disappeared, blue light and all, right in front of me. By now I was in the fog and could see about a car length ahead. It got worse very fast. And I remember this quietness, this short silence, and hearing a voice inside me tell me to pull over on the shoulder. I did, and about one second later there was a terrible crash right next to me. My window was down and glass flew into the car and all over me. I wasn't cut. I jumped out and started running south, back down the highway. I was thinking, "Oh, please, God, don't let this happen to anybody else." And I started flagging down anybody I could. The sounds were awful. Screams and explosions and crashes.

There was this propane tanker that stopped when I waved it down, and then—it was horrible—this Toyota crashed into the rear of it, and one of those piggyback trucks smashed into it. The Toyota just crushed to nothing, it was about three feet long and somehow, miraculously, an 11-year-old girl got out of it. [Her grandmother, the driver, was killed.]

TOM GRAHAM, 35, of the Tennessee Highway Patrol, whom Whaley saw pass, was the first trooper on the scene: The dispatcher called and said there was a massive problem near exit 36.1 started running into fog as I approached that exit. It was like suddenly having a blanket thrown across your windshield. The first thing I saw was a tractor-trailer stopped in the right-hand lane. I went left onto the median to avoid hitting it. while the red pickup behind me crashed into it. The drivers got out, and we all just stood there. At times you couldn't even see your shoes. We heard the sound of brakes as another, oncoming tractor-trailer sideswiped the red pickup. We could hear crashes everywhere. There was no safe place to be. The median was no safer than the middle of oncoming traffic, with cars swerving in all directions. There was also no safe way to drive. It wasn't safe to go fast, of course, but it wasn't safe to slow down or stop either.

That Toyota that was mashed between the tanker and the tractor-trailer—it actually cushioned the crash between the two trucks. And the tanker was carrying 10,000 gallons of propane. It took 12 minutes to close off the interstate, but a lot happened in such a short time.

RODGERS: While I was flagging down cars, this guy came up to me and said, "That lady in the van right there is dead." We could hear explosions. Cars were blowing up, and you could hear people screaming in the distance. All of a sudden this group of people came out of the fog walking up the middle of the road. They
had this blank stare on their faces, and we said, "Where are you from?" They said they were from the southbound lanes and that there was a chemical spill there and no one could breathe. So that added to the stress of the situation. Just one thing after another. The thought that all these people just got up that morning just like I did and nobody knew they were going to die that day. It happened so fast.

WHALEY: You could smell the gasoline, and you could smell this terrible smell that you knew was hair burning.

But there were nice things too. At one point three truckers, whose names I don't know, and I had prayer together. We just stood there and held hands and prayed.

Finally, at around 11:30 A.M., the fog lifted.

RODGERS: When it lifted, it went away in five minutes. It was like someone just blew it away. Once again, just like that, it was a bright, blue, sunshiny day, beautiful. We'd been there two hours; it seemed like a week. Then for the first time we could see the whole expanse, the smoke and the wreckage, and it was unbelievable.

CLARK: One trailer was actually melted. You just can't believe you could be puttin' along on a nice day and be about five miles from where you're going and get in the middle of something like that.

RODGERS: I keep seeing those cars. You see those vehicles reduced to nothing, and it makes you realize how vulnerable you are.