Idaho frost law restrictions 2021.



2021 Idaho winter frost/spring thaw laws and seasonal weight restrictions.

During the spring months when warmer temperatures cause the road surface to break up and generally deteriorate, the highways most affected are restricted to lower axle weights and speed restrictions.
The District will sign and mark affected state highways the day before the weight and/ or speed restrictions are in effect. The weight and/or
speed restrictions will be enforced the day after the Districts sign and mark the state highway.
On those sections of highways which are posted for legal weight, or to less than legal weight, trucks and buses weighing 10,000 pounds or
more will be restricted to 30 mph in critical areas. Speed zones will be marked with red and yellow markers. A red marker will mean speed
is restricted to 30 mph and a yellow marker will mean that legal speed can be resumed.
For information on operating restrictions for state highways posted for spring breakup limits or to check on a route of travel for construction
restrictions etc., go to 511.Idaho.gov and the trucking page.
It is important for the trucking industry to cooperate and comply with the load and speed limits. If compliance with the load and speed limits
are adhered to, the need for future, more restrictive, limits may be alleviated. Excessive violations may lead to the implementation of more
restrictive limits.

Live map.

This is a excellent reference and resource point for Idaho chain laws and basic seasonal weight restriction information.

 

See also:

Tire chain laws.
Tire chain laws by location.
Trucking regulations.
Federal bridge formula.
Exemptions from seasonal restrictions.

 

Iowa State Shipping Regulations 2021

2021 Iowa state shipping regulations, limitations, rules and laws in the state of Iowa.

 

Iowa



Iowa State Trucking Permit Regulations – oversize shipping and transport.

Legal Loads.

Length: 53’ trailer
Weight:  GVW = 80,000 lbs. Steer 20,000 lbs.
Width: 8’ 6”
Height:  13’ 6”

Routine oversize shipping, trucking and transport permits.

Length:  120’
Weight:  5 axles 92,000 lbs., 6 axles., 7 axles 132,000 lbs.,
Width:  18’
Height:  16’

How to apply for trucking permits.

Iowa DOT
Phone: 515-237-3264
Fax: 515-237-3257

Permits are valid for 5 days.  Single trip oversize trucking permit costs $10. Iowa State Trucking information site.

Pilot Car – Escort Car Requirements.

Length: 80’ to 100’ must have revolving lights.  Over 120’ requires 1 rear pilot/escort vehicle. 10’ overhang requires flashing lights.
Weight: Over 80,000 lbs. GVW requires amber lights.
Width: On Primary Road  Over 12’     1 front pilot car escort vehicle is required. On 2 lane over 14’ one rear pilot car escort vehicle is required. On 4 lane over 14’6” one rear pilot car escort vehicle is required.  On Interstate over 16’6” one pilot car escort vehicle or lighting is required.
Height:  Over 14’4” requires 1 front pilot car escort vehicle with height pole.

Travel Restrictions.

Travel is permitted from ½ hour before sunrise to ½ hour after sunset 7 days per week (see holiday and event traffic below). Trucks can travel 24/7 if the shipment is less than 11’ wide, 100’ long and 14’4” wide.

Holidays and event traffic.

Iowa code specifically states the designated restricted movement holidays are Memorial Day, Independence Day, and Labor Day. No movement will be allowed on these holidays or after 12 noon on days preceding these holidays and holiday weekends that include holidays falling on Monday, except as provided for in Iowa Code 321.457.

Note: If you are not in excess of the following weights/dimensions continuous travel may be permitted. 

Width: 11′.
Height: 14′ 6′
Length: 100′
Weight: Under legal limits.

Always refer to your permit first before movement. If you are not specifically clear on the complete instructions contact the Iowa DOT by phone: 515-237-3264.

The information contained in these pages is research information primarily for use by oversize and overweight trucking company drivers, dispatchers and pilot car companies. While every effort is put into maintaining the accuracy of this information you must absolutely verify this information with the Iowa State DOT Permits office before commencing movement.

iowa-state

2021 frost winter frost laws, thaw laws and weight restrictions.

2021 frost laws, thaw laws and seasonal weight restrictions.

Frost/thaw damages to surface.

Frost/thaw damages to surface.

Learn the details of the winter frost laws, spring thaw laws and seasonal weight restrictions. Details for the USA and Canada by State/Province. Many areas incorporate temporary special weight limits and restrictions (frost or thaw laws) during the winter and spring months of the year. These temporary restrictions are usually referred to as “frost laws” or “thaw laws” and implemented typically during the month or March and April. In some Northern States and Provinces frost laws can still be in effect in July as it’s much colder in the North. Since these restrictions are implemented on a “as needed” basis it is possible many of the official government websites may not have published this temporary restriction in a convenient place as frost laws are also subject to change at any moment based on the temperature of the roads core. You want to be certain to check with the appropriate officials to verify the latest changes in the laws.

2021 United States: Restrictions on winter and spring seasonal weight laws.

Idaho   Iowa   Maine   Michigan   Minnesota    Montana   Nevada    New Hampshire    New York   North Dakota  Pennsylvania    South Dakota    Vermont   Washington    Wisconsin    Wyoming

2021 Canada: Restrictions on winter and spring seasonal weight laws.

Alberta   British Columbia   Manitoba   New Brunswick New Foundland & Labrador  Nova Scotia  Nunavut  Ontario    Prince Edward Island   Quebec    Saskatchewan

Why we have these laws and must protect our roads and highways.

In order to keep the trucking industry operating the Northern US states and Canadian provinces rely on engineers and scientific data to determine which dates frost laws will be in effect. With fairly recent advances in science and technology, data is much more reliable. This helps with the implementation of “Frost Laws” or “Seasonal Weight Restrictions” ensuring they are not implemented to early or late. While no State or Province desires to delay the transportation of goods through their territory it is imperative public assets are protected.

In areas that constantly get negative (ie: -10 below zero) temperatures the amount of damages has forced Northern US States as well as Canadian Provinces to create and enact laws that restrict vehicle weights during the spring and winter months (specifically trucking companies) when the roads and bridges are thawing out. There are all kinds of things that can go wrong with different types of roads and pavements. For example the State of Michigan has implemented permanent frost laws that go into effect during the months of March through May (and in some cases even June). Some routes require legal axle weight limits be decreased by as much as 35%. Some areas and local governments may also limit heavy-haul vehicle speeds to a maximum of 35 miles per hour during frost/thaw law months regardless of posted limits.

Oregon hwy. US 1. Photo courtesy of KDRV.com

One of many examples is in Southern Oregon on old US Highway 1 (which follows the coast line from Mexico to Canada) the road is as much as 16 feet thick as years of pavement (even bricks) has been laid down year after year since the early 1900’s. It should be noted that today’s technology is able to provide us with roads that are flexible due to the engineering of the construction process and the materials used. Excessive weight exerted by overloaded axles (or a weakened supporting base) can cause the pavement to bend or deform. The strength of the road combined with its resistance to bending determines the amount of weight the roadway can handle.

 

See also:

Tire chain laws.
Tire chain laws by location.
Trucking regulations.
Federal bridge formula.
Exemptions from seasonal restrictions.

Iowa frost law restrictions 2021.

2021 Iowa frost laws, seasonal load weight and restrictions.

 

In previous years the general rule seasonal restrictions typically begin around March 15th each year in Iowa. By no means consider this legal advice. Be sure to consult with the Iowa DOT before attempting to travel.

 

Current Iowa route restrictions by Iowa counties map.

Iowa DOT office: 515-237-3264

For more information about Iowa regulations and restrictions try our “Trucking regulations” link below.

See also:

Tire chain laws.
Tire chain laws by location.
Trucking regulations.
Federal bridge formula.
Exemptions from seasonal restrictions.

 

2021 Federal Bridge Formula Weights Explanation.

2021 Easy – Federal Bridge Formula weights explanation.

The Federal Bridge Formula explanation.

Heavy-haul truck drivers should know exactly how to calculate the Federal Bridge Formula. Below is a very simple explanation to ensure compliance.

Explaining the maximum weight any combined set of axles on a truck and trailer can carry to cross a bridge on the Interstate highway system.  The following Federal bridge formula is used for calculating acceptable weights:

W=500 [ LN/N-1 + 12N + 36]

W= the overall gross weight on any group of two or more consecutive axles the the nearest 500 pounds.

L= the distance in feet between the outer axles of any group of two or more consecutive axles.

N= the number of axles in the group that are under consideration.

How do I determine Bridge Formula?

THIS IS A PERFECT EXAMPLE: Bridge formula is 30 times the wheelbase* in centimeters plus 18,000 kg.

*Wheelbase in the above Bridge Formula calculation refers to the maximum axles span (center of the first axle to the center of the last axle of any axle group) in a heavy commercial vehicle.

Axle spacing is another consideration that must be taken into account when looking at the Federal weight compliance laws.  In order to properly protect our bridges the number and the spacing of truck and trailer axles carrying the shipment must be calculated.  So a bridge weight formula applies when the gross weight on 2 or more consecutive axles exceeds the limitations on the formula, except that the 2 consecutive sets of tandem axles may carry a gross weight load of 34,000 pounds each if the overall distance between the 1st and last axle is  over a 36 feet minimum.

Exceptions to the Bridge Weight Formula:

There are exceptions.  Federal law does include an exception to the Federal Bridge Formula and the bridge table. 2 consecutive sets of tandem axles may carry 34,000 pounds each IF the overall distance between the first axle and last axles of these tandems is 36 feet or greater.  For example:  a 5 axle tractor semi trailer combination may carry 34,000 pounds of weight both on the tractor tandem (axles 2 and 3) and the trailer tandem (axles 4 and 5), provided the axles 2 and 5 are spaced at least 36 feet from each other.  Without this exception the bridge formula would allow for actual weight of only 66,000 pounds to 67,000 pounds on tandems spaced 36 feet to 38 feet apart. (References: U. S. Department of TransportationFederal Highway AdministrationFederal Bridge Formula Weights” – FWHA-FBFWHA-FBFF the .pdf)

Note:  In addition to the above formula weights Federal law says that a single axle is limited to a maximum of no greater than 20,000 pounds and that axles that are closer than 96 inches from each other are limited to a maximum weight of 34,000 pounds.  Also that gross vehicle weight be less than 80,000 pounds.

Federal law (23 U.S.C. 127) does include an exception to the Federal Bridge Formula and the Bridge Table—two consecutive sets of tandem axles may carry 34,000 lbs. pounds each if the overall distance between the first and last axles of the tandem axles is 36 feet or more. For example; a five-axle tractor and semitrailer combination may carry 34,000 lbs. pounds both on the tractor tandem (axles 2 and 3) and the trailer tandem (axles 4 and 5), if axles number 2 and 5 are spaced at least 36 feet apart. Without this exception the Federal Bridge Formula would allow an actual weight of only 66,000 pounds up to 67,500 pounds on tandems spaced 36 to 38 feet apart.

2020 Federal Bridge Weight Chart

2
axles
3
axles
4
axles
5
axles
6
axles
7
axles
8
axles
9
axles
Less than 8’3″34,00034,000
More than 8’4″38,00042,000
939,00042,500
1040,00043,500
1144,000
1245,00050,000
1345,00050,500
1446,50051,500
1547,00052,000
1648,00052,50058,000
1748,50053,50058,500
1849,50054,00059,000
1950,50054,50060,000
2051,00055,50060,50066,000
2151,50056,00061,00066,500
2252,50056,50061,50067,000
2353,00057,50062,50068,000
2454,00058,00063,00068,50074,000
2554,50058,50063,50069,00074,500
2655,50059,50064,00069,50075,000
2756,00060,00065,00070,00075,500
2857,00060,50065,50071,00076,50082,000
2957,50061,50066,00071,50077,00082,500
3058,50062,00066,50072,00077,50083,000
31
59,00062,50067,50072,50078,00083,500
3260,00063,50068,00073,00078,50084,50090,000
3364,00068,50074,00079,00085,00090,500
3464,50069,00074,50080,00085,50091,000
3565,50070,00075,00080,50086,00091,500
3666,00070,50075,50081,00086,50092,000
3766,50071,00076,00081,50087,00093,000
3867,50071,50077,00082,00087,50093,500
3968,00072,50077,50083,50088,50094,000
4068,50073,00078,00084,00089,00094,500
4169,50073,50078,50084,50089,50095,000
4270,00074,00079,00084,50090,00095,500
4370,50075,00080,00085,00090,50096,000
4471,50075,50080,50085,50091,00096,500
4572,00076,00081,00086,00091,50097,500
4672,50076,50081,50087,00092,50098,000
4773,50077,50082,00087,50093,00098,500
4874,00078,00083,00088,00093,50099,000
4974,50078,50083,50088,50094,00099,500
5075,50079,00084,00089,00094,500100,000
5176,00080,00084,50089,50095,000100,500
5276,50080,50085,00090,50095,500101,000
5377,50081,00086,00091,00096,500101,500
5478,00081,50086,50091,50097,000102,000
5578,50082,50087,00092,00097,500102,500
5679,50083,00087,50092,50098,000103,000
5780,00083,50088,00093,00098,500104,000
58
84,00089,00094,00099,000104,500
59
85,00089,50094,50099,500105,000
60
85,50090,00095,000100,500105,500