US-93

Welcome to the online hearing for a 129,000 pound (129k) route application affecting a portion of US-93 in Custer and Butte counties. The requested route is approximately 78 miles from milepost 82.60 to milepost 160.38. The comment period for this hearing closes June 23.

Comments will be reviewed by ITD before a decision is reached. A decision could come as early as July.

 Download application map. 

Amalgamated Sugar Company is applying to utilize commercial loads up to 129,000 pounds on a segment of US-93 for the transportation of lime rock from the US Calcium mine near Darlington to their plants in Twin Falls and Paul.

The purpose of the application is to more efficiently transport 200,000 tons of rock. The route is currently permitted for loads up to 105,500 pounds. Amalgamated Sugar is projecting 4,700 annual trips with loads weighing up to 129,000 pounds versus 5,700 annual trips with loads weighing up to 105,000 pounds.

 You can read the application by clicking here. 

This 78 mile segment of US-93 is a two lane rural principal arterial route with a mix of flat and rolling agricultural and high desert lands passing through the communities of Arco, Moore, Darlington, and Mackay.

The highway can accommodate an overall vehicle length up to 115 feet and a 6.50-foot off-track. Loads weighing up to 129,000 pounds would meet these safety requirements.

All 17 bridges on the segment of highway are already capable of safely carrying 129,000-pound loads.

This segment of highway is asphalt in generally good condition, and is not considered deficient. The speed limit of this section of highway varies between 25 and 65 mph, with traffic volumes ranging from 580 to 2,000 vehicles per day on average. Truck traffic accounts for 2 to 21 percent of all traffic.

There are no runaway truck ramps along this segment of US-93. There are also no permanent or roving Port of Entry sites.

Between 2016 and 2020, there was a total of 146 crashes on this segment of highway which resulted in 50 injuries and five deaths. Of the total crashes, seven involved a tractor-trailer. One of the five deaths also involved a tractor-trailer but no other injuries resulted from the crashes involving tractor-trailers.

There is one church and no other social facilities on this segment of US-93. There is a bike path from milepost 108.8 to milepost 109.24 between lane of travel and parking. No signalized intersections are on this route.

For specific data on pavement conditions, traffic volumes and crashes, read the engineering evaluation.

ITD engineers have evaluated the conditions of the bridges and road as well as safety data for the highway section included in this application. The analysis determined the route is appropriate for 129,000-pound loads. No improvements are necessary for this route to support 129,000-pound trucking, and no additional costs will be passed on to taxpayers.

You can review the full analysis by clicking the button below.

Trucks on highways generate noise, especially impacting residents along rural highways. ITD has heard concerns that heavier trucks will produce more noise. However, in an analysis of noise generated by various truck sizes, ITD has found that heavier trucks do not create more noise than trucks already allowed on these highways.

In regards to compression brakes, ITD does not have the authority to regulate the trucking industry. Those standards are created by the Environmental Protection Agency and enforced by local and state law enforcement agencies.

The primary difference between a 129,000-pound load and a load that weighs 105,500 pounds is of course the weight. Most people can't tell the difference, but visually you can usually identify the heavier load by its extra axles or sometimes the addition of a pup trailer.

To the left, you can see the different legal configurations for commercial vehicles. At the bottom are the configurations for 129,000-pound loads.

Notice how the 129,000-pound configurations require more axles. This spreads out the load over a greater surface area, reducing the impact to the roadway. In testing, ITD has found that 129,000-pound loads are actually less damaging than lighter loads with fewer axles.

More axles also means more brakes. Depending on the type of brakes and how well they are maintained, 129,000-pound trucks can stop as quickly as lighter trucks already on the highway. Heavier trucks are still required to meet stopping standards identified in state and federal regulations.

•  Download existing 129,000-pound routes. 

Before submitting your comment, please finish reading the FAQs below. Written comments can be emailed to officeofthechiefengineer@itd.idaho.gov or mailed to the attention of Freight Program Manager Scott Luekenga at P.O. Box 7129 in Boise, Idaho 83707. Oral testimony can be recorded at (855) 790-4988.

If you have questions you would like to discuss before giving comment, you may call Freight Program Manager Scott Luekenga at (208) 334-8057.

In your comment, be sure to clearly identify whether you support or oppose this application and why.

Q: Why does Idaho have a 129,000-pound route program?

A: In 2013, at the request of the trucking industry, Idaho Legislature authorized the permitting of trucks weighing up to 129,000 pounds to operate on designated Idaho highways. The permitting of 129,000-pound trucks allows for combining shipments, which in turn decreases the number of trips a truck must make, supporting Idaho’s agricultural, forestry, mineral and manufacturing industries. Furthermore, the 129,000-pound route program reduces congestion on state routes, provides for a safer highway system and reduces impact of trucking on the environment.

Q: What are the applicable laws governing the 129,000-pound program?

A: Below are the applicable laws:

• Idaho Code Title 49, Motor Vehicles, Chapter 10 – Weight, Speed and Tire Regulations
• IDAPA 39.03.03 Rules Governing Special Permits - General Conditions and Requirements
• IDAPA 39.03.06 Rules Governing Special Permits for Extra-Length Excess Weight, Up to 129,000 Pound Vehicle Combinations
• IDAPA 39.03.22, Rules Governing Over Legal Permits for Extra-Length Vehicle Combinations

Q: When did Idaho start allowing 129,000-pound trucks?

A: In 2003, as a result of ITD receiving an application to allow trucks weighing up to 129,000 pounds, the Idaho Legislature passed House Bill 395, which created a pilot project to test the effects of increasing the legal truck weights on state highways. The pilot project revealed no adverse impacts to Idaho highways, so in 2016, the 129,000 Pound Program was officially adopted. The interstate system (I-84, I-86, I-15, I-90, I-184) was approved by the federal government on July 1, 2016, to allow 129,000-pound trucks.

Q: What criteria does ITD use to conduct its evaluation of a route in order to ensure the route is suitable for 129,000-pound trucking?

A: ITD operates with the mission of safety, mobility and economic opportunity for all motorists on the state highway system. Criteria used to analyze a route includes a safety analysis of vehicle accidents and fatalities, an assessment of pavement and bridge cracking, roughness or ruts and the route's ability to accommodate off-tracking requirements to include route width and curvature. Additional emphasis is given to residential areas and social infrastructure along with residential and commercial traffic volume.

Q: Is there any reduction of overall trucks on highways as a result of the 129,000-pound program?

A: Reduction in truck traffic varies dependent on the applicant, route, commodities and time of year. Estimates range from 12 percent to 20 percent in reduced truck traffic on approved 129,000-pound routes.

Q: How is a 129,000-pound route approved?

A: Routes are approved by the Idaho Transportation Board following a thorough review of the route. Reviews consist of route analysis and public involvement. Analysis are conducted by ITD’s Office of Highway Safety, Office of Bridge Asset Management, Division of Motor Vehicles and the applicable ITD District Engineer. Public comments are sought during the review process and are incorporated into ITD’s final evaluation, which is presented to the 129,000 pound Subcommittee. The 129,000 pound Subcommittee reviews the evaluation and either endorses or doesn’t endorse the application. The application evaluation is presented to the Idaho Transportation Board for approval or disapproval of the route. If approved, the route goes into effect 14 calendar days after the Transportation Board approves the application.

Q: Do trucks which are over legal limits require a permit to drive on routes approved for 129,000 pound operations?

A: Yes. When a route is designated a 129,000-pound route it means the route has been designated as such and meets all requirements per Idaho Code. All trucks operating on these highways must still be permitted to operate on a 129k approved route per Idaho Rules and Code.

Q: Who grants permits for trucks weighing up to 129,000 pounds on state and federal highways?

A: The Idaho Department of Motor Vehicles is the executive permitting agent for trucks operating on highway systems within Idaho.

Q: Who approves a route for trucks weighing up to 129,000 pounds on local roads?

A: The Local Highway Jurisdiction (LHJ) has the authority to approve a 129,000-pound route request for routes within the local highway’s jurisdiction.

Q: Who can apply for a highway to be designated for a 129,000-pound-use highway?

A: Any company or owner or operator of an overweight or oversized vehicle can apply for a route to be designated as a 129,000-pound route.

Q: Won’t heavier trucks go slower on the highways and cause congestion while ascending a hill?

A: Oversized vehicles must abide by Idaho rules and code regarding speed or at safe speeds given road and environmental conditions on highways. Oversized vehicles must maintain a minimum speed limit of 20 mph while ascending any grade.

Q: What are the non-permitted weight limits on interstates and highways?

A: The Federal Highway Amendment Act of 1974 established allowable legal weight limits on Interstate System Highways at 20,000 pounds for single axles, 34,000 pounds on tandems and total gross loads not exceeding 80,000 pounds.

Q: What are the non-permitted weight limits on non-interstate highways?

A: Allowable legal weight limits on non-interstate highways are set at 20,000 pounds on single axles, 37,000 pounds on tandems and total gross loads not exceeding 80,000 pounds

Q: Do trucks authorized to weigh up to 129,000 pounds damage pavement more than trucks weighing up to 80,000?

A: The impact of a 129,000-pound on pavement structures is less than an 80,000-pound truck by 21 percent. This is because of disbursement of weight among additional axles and the spacing of the axles allows the weight to spread over a greater area, thus reducing the impact on routes.