What's behind the spike in fatal traffic accidents?

The U.S. is on a pace for what could be the deadliest year on the roads since 2007. According to the National Safety Council, between January and June, about 18,630 people died in traffic accidents across the country -- that's up 14 percent from the same period in 2014 -- and more than 2.2 million were seriously injured.

One factor contributing to the uptick in fatal crashes is the improving economy, National Safety Council president former NTSB chairman Deborah Hersman said.

"They have more disposable income, more Americans are employed, and so they're driving to work, they're taking longer vacations and they're just putting more miles on their car," Hersman said Monday on "CBS This Morning." Gas prices are also 30 percent lower than last year.

Summertime in particular is a deadly period, Hersman said.

"We see spikes in distracted driving, in speeding, and in impaired driving. Lots of weekend parties, long holidays, a lot of alcohol is consumed and so unfortunately we see an uptick in those impaired driving crashes," Hersman said.

Drinking, speeding and using your phone while driving is a "triple threat of danger" on highways, but there's more to danger than just texting and driving.

"It's all distractions. People have got to stay focused on the road," Hersman said. "It just takes a split second, but that's why we see those fatality and injury numbers going up."

Carpooling, particularly for teens who are three times as likely to get into an accident, can also increase the risk of danger on the roads because of said distractions.

"Each additional passenger in the car increases their crash risk -- 44 percent for one additional passenger, and four times the crash risk with four kids in the car. So it's much safer, even though you've got more cars on the road, to keep those kids separated and let them drive themselves to school rather than carpool," Hersman said.

Costs related to crashes are also increasing, with the estimated bill for traffic deaths, injuries and property damage at $152 billion, 24 percent higher than last year.

To be safer on the road, the National Safety Council recommends:

  • Buckle up every passenger on the drive
  • Have a designated driver or arrange alternate forms of transportation
  • Get enough sleep and take regular breaks to avoid fatigue on roads
  • Never use cell phones behind the wheel, not even hands-free
  • Read the Council's "My Car Does What?" and learn how to use your car's safety systems