An Arizona lawmaker wants to remind slow drivers — frequently — that state law requires them to stick to the right lane.

Rep. Bob Thorpe, R-Flagstaff, has introduced a bill that would require the Arizona Department of Transportation to place signs with the reprimand every 50 miles on rural state highways.

He wants the state to spend $200,000 on the effort and have the signs in place by 2022, installing then as they conduct other maintenance work along the roads.

Arizona has about 10,500 miles of rural state highways, counting each mile in both directions, according to ADOT.

"This is what both Oklahoma and Texas do to try to remind people not to impede the left lane," Thorpe said. "It was a request from constituents up in my district asking for this."

Thorpe said he approached ADOT about the idea and the 50-mile intervals were their suggestion. So was keeping the signs to rural areas, he said.

"When you are in the metro areas, the Phoenix area, you don't want to necessarily restrict all lane use," Thorpe said. "You want to keep as much flow going as possible."

I-17 grade north of Phoenix is an annoyance

Thorpe travels frequently between his home in Flagstaff and the Capitol on Interstate 17, and said he sees his share of annoyingly slow drivers in the left lane.

"When you go past Black Canyon City, it is a pretty steep grade," he said about the northbound side. "What will happen on that grade is you have a truck doing 45 passing one doing 44. And that truck will be in the left lane for the next three or four miles if not longer."

He said on a recent trip heading southbound downhill on that same stretch, he saw a flatbed truck stay in the left lane for the entire length of the hill.

He proposed a similar law last year without an appropriation tied to it that didn't advance, he said.

"Last year when I ran the bill, I must have had 20 or 30 people approach me at the Capitol," he said. "They were irked. This is a pet peeve for them."

State law already includes a passage directing slow traffic to stay right, that reads:

"On all roadways, a person driving a vehicle proceeding at less than the normal speed of traffic ... shall drive the vehicle in the right-hand lane then available for traffic ... except when overtaking and passing another vehicle ... or when preparing for a left turn."

The fines for violating that statute are set by local justice courts, according to Department of Public Safety spokesman Bart Graves.

Thorpe's bill says that by Sept. 1, 2022, ADOT "shall erect signs every 50 miles on highways in rural areas notifying the public of the requirements of this subsection."

His bill does not include required language of the signs, though black and white signs that read "Slower traffic keep right" are commonly used for such purposes.

House Bill 2535 has been assigned to Transportation and Appropriations committees and has not yet been scheduled for a hearing.