Why This Fourth of July Could Be Among the Deadliest in Recent Years on the Highways

— -- An estimated 35 million Americans will be on the roads this holiday weekend, according to AAA, and this year could be one of the deadliest in recent memory -- due to drunk drivers, experts said.

The National Safety Council, a nonprofit group, estimates that about 400 Americans will die on the roads this weekend, with drunk driving being the leading cause of fatalities.

"The combination of low gas prices and an improving economy is resulting in more miles being driven on our roads, unfortunately resulting in an increase in the number of deaths," said Ken Kolosh of the National Safety Council.

The Ford Motor Company has a kit using weights and goggles that mimics the effect of drunk driving, and ABC News tried the devices to get a feel for how much control a motorist loses when driving drunk. The sensation is similar to vertigo.

While I strapped on the kit, U.S. Park Police Sgt. Adam Zielinski put me through the paces of a DUI stop, and I was staggering, unable to walk even nine steps in a straight line.

"Do you think that you were able to operate a vehicle safely?" Zielinski asked.

The answer was a clear no when I couldn't even get one foot in front of the other.

And it's not just gas prices that this officer is worried about, it's the calendar, too, because today, a Friday, is a legal holiday, and Saturday is the Fourth of July.

"So you have the possibility of people attending two different events, on a Friday and a Saturday," Zielinski said. "There's just a culmination of different effects that could really be an integral part on how highway safety is this weekend."

Heather Wedel, a spokeswoman for Mothers Against Drunk Driving, said that through through July 5, people can go to Uber.com/MADD and take the pledge to not drink and drive. Uber will match every donation made to MADD through this pledge page, dollar for dollar, up to $25,000, Wedel said, noting that the funds raised will be used to serve victims of drunk driving.