Legislators are expected to weigh a bill allowing trucks to pull loads up to 129,000 pounds on approved state highways.

The current limit on many highways is 105,500 pounds. However, a decade-long pilot program has allowed the heavier weight on some highways in southern Idaho and an Idaho Transportation Department report states that amount hasn't had a significant effect on the roads and safety.

Proponents of the bill, which has been printed but not heard yet by the Senate Transportation Committee, say it would promote interstate commerce because some neighboring states have higher truck weight limits and it would mean fewer loads to get goods to market, saving money and time.

"We need to have the same for Idaho so our local industries have the same benefit and can successfully compete in increasingly global markets," said Jim Riley, a Coeur d'Alene attorney who represents a group of shipping and trucking interests.

But Lynn Humphreys of the Post Falls Highway District and a Kootenai Metropolitan Planning Organization board member said he believes having the heavier weight allowed on highways statewide would be a mistake.

"There's concerns about the impact it would have on single-span bridges," he said.

He also said many of North Idaho's curvy and mountainous highways aren't as conducive to the heavier loads as the longer, flat stretches in southern Idaho are.

Humphreys said the Idaho Association of Highway Districts is fine with allowing the highways approved in the pilot program to continue to have heavier loads, but doesn't support expanding the routes into North Idaho.

He said the long-term road effects, including those associated with approved routes under the ITD study, remain sketchy.

"I don't believe they've gone far enough with the study to make a really intelligent determination whether they've harmed any bridges and roads down there," he said.

Riley said the increased capacity on any state highway would need approval from both the Idaho Transportation Board and local jurisdictions.

The bill does not pertain to interstates and makes the routes under the pilot project permanent. The pilot program granted by the Legislature expires in June.

The Idaho Transportation Board has not taken a position on proposals relating to truck weights.

Bills dealing with increasing capacity on Idaho's highways have been floated multiple times before.

"This issue comes up fairly often and will continue to do so as businesses try to move their products less expensively," said Sen. Shawn Keough, R-Sandpoint.

Post Falls Mayor Clay Larkin said the city has previously opposed such measures due to public safety and road preservation concerns.

He said the opposition still stands today.

But proponents say the bill makes roads safer, will mean less wear on the highways and is a win for the environment because raising the weight limit will take one out of every five trucks off the road due to less trips for shippers.

Truck study

• For more information on the state's pilot program featuring a 129,000-pound limit on trucks on highways in southern Idaho, visit http://itd.idaho.gov/newsandinfo/Docs/129000 Pound Pilot Project Report.pdf.