IOWA CITY, Iowa -
Traffic will be filling Interstate 80 and other roads this Fourth of July weekend.
The lowest gas prices in more than a decade is fueling summer's busiest holiday.
It's also prompting awareness of drowsy driving.
"You can't be on drugs," said Dr. Corinne Peek-Asa, University of Iowa. "You can't be too sleepy. You can't be drinking, and you have to pay attention."
On Wednesday, traffic was leading to the University of Iowa.
That's where the College of Public Health hosted its first-ever Drowsy Driving Summit.
Like drinking, drugs and distractions, drowsy driving can be deadly.
"It diminishes your awareness and reaction time," said Mark Lowe, Iowa Department of Transportation. "Those are two of the main protectors when you're driving."
Drowsy driving is one factor in Iowa and Illinois already reporting more highway deaths this year.
During the summit, participants got to check out a unique driving simulator.
It helps researchers to study accidents while learning ways to prevent them.
"Understanding how medications affect people, how sleep deprivation affects people," said Dr. Peek-Asa. "It gives an environment to manipulate those things without putting anybody at risk."
As millions of cars head out this weekend, this partnership sends a powerful message before hitting the road.
Lowe suggests never trying to drive for as long and far as possible without taking a break.
"Take regular breaks," Lowe said. "Switch drivers, maintain your awareness and really consider your safety the whole way there."