The bill passed the Senate easily, but this week it just squeaked through the House by three votes with opponents saying -- hold on, not so fast.
"Our bottom line is, is this is for safety?" said Dave Carlson with AAA of Idaho. "Show us how it accomplishes that task."
What really concerns the AAA is the difference in speeds that would be created between slower moving trucks and faster moving cars.
"What we are going to do is raise speed on higher ends for cars and those trucks that do not have speed limiters," Carlson said. "So essentially you spread the range between the slowest and fastest vehicles on the roads."
Carlson says that's a recipe for more crashes.
Sen. Bart Davis, (R) Idaho Falls, sponsored the bill.
"I share the concerns for safety," said Sen. Davis, also the Senate Majority Leader. "And that is why the bill was written the way it was."
Davis points out the legislation doesn't raise speed limits everywhere, but gives the Idaho Transportation Department (ITD) the power to decide where to raise the speed limit and by how much -- after engineer and safety studies.
If the bill is signed into law, there's no specific date when speed limits would go up, the timing and locations would be determined by ITD, working with the Idaho State Police.
"Most important -- look at it from a life-safety view," Davis told KBOI News.
The senator says people in Idaho are already driving 80 or 85 miles per hour and the law needs to safely catch up with the times.
Utah recently passed a similar bill, and in Texas, the interstate speed in some places is 85 mph.