Albany -- There are close to two million tractor trailer rigs on our nation's highways.
And while most of them safely make their deliveries every day, it's the ones who don't that we hear about.
Because of the size and weight of the trucks, tractor trailer collisions typically have tragic results.
The big trucks are all around us, from busy interstate highways to narrow back roads, and they can be intimidating to motorists in much smaller vehicles.
Corey Cashion says, "I get a little scared every time I pull up next to one."
That's a common reaction because we've seen the deadly results of truck crashes. In February, a big rig barreled out of control up I-75 in Turner County. Police still don't know why he drove across the median and into oncoming traffic. He crashed and exploded and was killed.
All the driving skills we're taught can't prepare us for an encounter like this. That's why the U.S. Department of Transportation requires truck drivers to get physical examinations every two years.
"There are certain things that would disqualify a driver right off the bat," says Elizabeth Yesbick.
Yesbick is a family nurse practitioner, certified by the DOT to examine truckers. The tests she gives are rigorous.
"How alert are they going to be? Do they have certain medications that could affect that? "Are they one certain medicines that affect their alertness and consciousness?" she says.
While the federal government requires a medical exam every two years for certification, the nurse practitioner or doctor who gives the exam can give truckers shorter medical certificates requiring more frequent exams.
Yesbick says, "For instance, if people have high blood pressure, but they're on medication and it's under 140 over 90, then they get a one year certification instead of the two."
Even shorter medical certificates are sometimes issued, as short as 90 days. That allows medical professionals to keep a closer check on the trucker, or does it?
"There's ways of getting around those laws and a lot of them do it", says Jim Luttrell.
Luttrell drove a truck for 56 years and there's not much he hasn't seen.
"A lot of times if there was a driver or two sitting out there waiting on a load, you'd give them a couple of bucks and they'd fill out the paper for you."
He says there was a time when doctors were frequently bypassed altogether, and medical certificates forged. Luttrell says things are a lot stricter nowadays, but even regular physicals can't guarantee that medical conditions won't arise.
"I had a physical in May and passed it with flying colors, and in July I had a stroke."
While on the road to Pennsylvania, he had a stroke that ended his career. Something that wasn't, and perhaps couldn't, have been detected just two months earlier when he had his physical.
"There are some signs we still look for and by having this every year or two years, even sooner under certain circumstances, then it does require them to come in and perhaps it would be a flag to have further testing for something like that," says Yesbick.
But that's assuming truckers see a doctor if they have medical problems between physical exams.
Jim Luttrell says that's not always the case.
"If a guy's gonna' truck, he's gonna' find a way to do it. A lot of times, rules and regulations don't slow you down," says Luttrell.
"Do you think there are some dangerous truck drivers on the road? 'Absolutely. There sure are,'" says Luttrell.
Larger trucking companies, like Southern Ag Carriers, keep close watch on when drivers' physicals are due.
"You have to stay on top of that, which the doctors that do that for us are D.O.T. certified to do that," says Carroll Harper.
His drivers get letters in the mail from Southern Ag prompting them when it's time for their physicals.
"As a driver, you get aggravated with it sometimes, but if you stop and think, it's for the best for the driver and the general public, also," Harper says.
The general public, in large part, has a fear of these big 18-wheelers. Sonja Giddens says, "They need to make sure they're certified so everybody can be safe."
But safety, says Jim Luttrell, comes down to one thing. "It all depends on the trucker when it comes right down to it."
Commercial truck drivers are held to a much higher standard than the rest of us. Their health is more-closely monitored and some medical conditions are deal-busters for their careers.
If they have seizures, even if controlled by medicine; if they are an insulin-dependant diabetic; or if their blood pressure is higher than 180 over 110, they will not be given a medical certificate.
Truckers want you to know something else - safety depends on you, too. Drive carefully when around these big rigs. Don't pull out in front of them, because no matter how badly they'd like to avoid hitting you, with all that weight they're hauling, it's usually impossible to stop in time to avoid a collision.
A study on driving behavior shows that automobile drivers are to blame 56 percent of the time in crashes with big rigs.