GRAYSON & FANNIN COUNTIES, TEXAS -- At 60 miles an hour, cars go whizzing by.

Now, a newly implemented state law is telling drivers they can go even faster.

In Grayson and Fannin counties, two stretches of highway are getting new speed limits.

"It'll increase to 75," David Selman with TXDOT said.

From the Oklahoma line through Sherman, highway 75 will increase to 75 miles per hour.

In Fannin County, the speed will also jump to 75 along the majority of 121 from south Bonham to the Collin County line.

"A lot of people are already driving those speed limits. So if you're on 75, a lot of people are already driving 75 in those sections," Selman said.

TXDOT studied drivers and found that on highway 75 and 121, drivers are more comfortable moving at a faster pace.

David says upping the speed limits could actually make drivers safer, but that belief isn't gaining momentum with everyone.

"I don't think it's a safe place now. With increasing the speed limits to a higher rate of speed, I think it just makes it more dangerous," Phil Johnson said.

Phil lost his teenage daughter Shelby in a car accident in 2007.

Shortly after her death, he founded Less Tears, More Years, a nonprofit that promotes safe driving.

"I don't think this is going to help. I think this is going to hurt. I think we're going to lose lives strictly because of the speed being a factor. And it's an unsafe speed," Johnson said.

The National Highway Traffic Safety Administration says that speed is one of the main causes of teen traffic fatalities.

"By increasing the speed limit, we're telling our teen drivers and everyone else that the road is safe enough to travel that speed," Johnson said.

The US Census Bureau on Transportation shows that in 2009, Texas had the second-highest fatalities in the nation for cars going over 55 on a highway.

The biggest speed limit increase is happening on the toll road that connects Austin to San Antonio. That highway will reach 85 miles per hour, making it the highest speed limit in the nation.