PowerPoint Presentation
ND Truck Weight Education
Leanna Emmer, NDLTAP Technical Resource Representative
With the current axle configuration under your vehicle, how much
weight can the vehicle legally gross?If you added additional axles
or increased the distance between axles would that increase that
vehicles carrying capacity...increase the amount of product your
vehicle can legally gross?Today, we are going to review the legal
axle weight and gross vehicle weight limits allowed on a
truck-tractor semitrailers traveling on NDs roadway system. We will
cover what elements are used to determine the legal weight limits
on a vehicle combination.
Go Live. Introduce the on-line ND Truck Weight Calculator. The
on-line truck weight calculator was created to enable a user a
motor carrier, government officials, law enforcement - to more
easily determine legal weight allowed on their truck-tractor
semitrailer when traveling on roadways in the state of North
Dakota. It was created so a user could more easily determine if
they were able to increase their vehicles weight capacity by adding
additional axles or increasing distance between axles.
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Legal Vehicle Weights
Vehicle Axle weights and gross vehicle weights for ND highway
system are set by law. Factors looked at when determining the legal
gross vehicle weight of a vehicle combination are the axle
configuration, tire width, and bridge length - measurements between
axles and axle groups . 2
Legal Gross Vehicle Weight
Laws set the maximum legal axle weight limits and gross vehicle
weight limits for North Dakotas road system.
****(screen)
When determining legal weights on a vehicle combination, the
factors used for the state/local road system are slightly different
than the factors used for the interstate system. 3
Axle ConfigurationSingle Axle Up to 20,000 poundsNumber of
tires/axle
Axle configuration is factor is determining allowable weight on
a vehicle combination.
Single axle, tandem axle, triple axle, split axle
Maximum weight on a single axle up to 20,000 poundsWhat defines
a single axle.... Measurement from axle center to the center of the
next axle is 8 feet or more.
Number of tires is also a determining factor - 2 or 4 tires.
Increasing the number of axles under a vehicle configuration,
may increase GVW limit allowed for that particular vehicle
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Axle ConfigurationTandem AxleUp to 34,000 poundsUp to 19,000
pounds/axle-state/local roadsUp to 17,000 pounds/axle-interstate
system
> 40 inches< 8 feet
Tandem axle is legal up- 34,000 lbs
What is a tandem axle??? 2 consecutive axles that have a
distance of more than 40 inches but less than 8 feet from hub
center to hub center.5
Axle ConfigurationGroup of 3 or more axlesUp to 48,000 pounds
state/local roadsUp to 19,000 pounds/axleDetermined by bridge
length interstate systemUp to 17,000 pounds/axle
> 40 inches
> 40 inches
Group of 3 axles, group of 4 axles.legal GVW on state/local
roads up to 48,000 poundsOn the interstate system, determined by
distance in feet/inches from the center of the 1st to the center of
the last axle in a groupFor state, local and interstate system,
require more than 40 inches from axle center to axle center in
order for each axle to be recognized as an individual axle. 6
Tire Width Linear and Metric
Tire width is a factor in determining legal weight on an
axleTire width from the manufacturers reading on the tire
sidewall.
No tire can exceed 550 pounds per inch of tire width weight
calculator does the calculation
The greater the tire width, the more weight allowed, not to
exceed the gross axle weight caps set by state law.
There is an exception
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Tire Width550 pounds per inch of tire width
Number of tires per axle
550 x 2 tires x 11 tire width = 12,100 pounds
550 x 4 tires x 11 tire width = 20,000 pounds
Number of tires per axle is also a factor.
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Exception
When travel is on the interstate system, the weight allowed on
the steering axle is determined by the manufacturers axle
raring.
The axle weight rating is stamped on a plate, which is generally
found on the inside driver door panel or inside the drivers
step.
Typically the axle rating ranges from 12,000 to 20,000 pounds.
It is dependant on the vehicle...what that vehicle is being used
for...heavy haul, over the road, etc9
North Dakota Axle Weight Limitations - Tire Width
Axle weight limitations chart show maximum legal axle weights
based on 550 pounds per inch of tire width calculation10
Bridge Length Federal Bridge Formula
Bridge length is also a factor in determining legal gross weight
on axle groups, combination of axle groups and the GVW
What is bridge length....start out by looking at the measurement
from axle center to consecutive axle centerThese distances from
axle center to axle center are used to determine bridge
lengths.
Bridge length is the measurement from the center of the first
axle in a group to the center of the rearmost axle in that same
group. Bridge length is the measurement from the center of the
first axle in a group of axles to the center of the rearmost axle
in the next group. Bridge length is the measurement from the center
of the first axle to the last axle of a vehicle combination.11
Bridge Length Interstate System
1294541146438917454367
Established when a vehicle is traveling on the interstate
system, must comply with interior and exterior bridge length
Start out by looking at the distance from axle center to
consecutive axle centerThese distances from axle center to axle
center are used to determine bridge lengths. Examples of interior
bridge lengthsMeasurement of 89 from the center of the first axle
in a group to the center of the rearmost axle in that same group.
Chart shows 89 = 43,000Measurement of 174 from the center of the
first axle in a group of axles to the center of the rearmost axle
in the next group. Steering axle to center of last drive axle 174 =
49,000 lbs. Or 543 is an interior bridge lengthIt is also the
measurement from the center of the first axle to the last axle of a
vehicle combination, exterior bridge length of 67 = 94,000 lbsBy
increasing the distance between axle groups, or increasing the
number of axles under a vehicle....MAY increase gross vehicle
weight allowed on a vehicle combination.12
Bridge Length State/Local Roads
12945411464367
On state/local road system, vehicles must comply with exterior
bridge length....measurement from the center axle on a tractor to
the center of the rearmost axle on a trailer.Start out by looking
at the distance from axle center to consecutive axle center.
Calculator will add those measurement to come up with exterior
bridge length for this vehicle combinationBy increasing the
measurement between axle groups, may increase gross vehicle weight
allowed on a vehicle combination.13
Weight limitations chart....Row at the top shows number of axles
in consideration.Left column measurement in feet to be
considered......
Ex: Bridge length measurement is used to determine gross weight
allowed on a group of axles...3 axles 8 ft = 42,000Bridge length
measurement is used to determine gross weight allowed on 2 or more
axle groups. 5 axle...46 ft = 77,000 lbs.Bridge length is
measurement is used to determine gross vehicle weight of a vehicle
or vehicle combination 14
Elements Axle/Gross Weights
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So when I worked for the ND Highway Patrol, a carrier would come
into the office or I would visit with them on the phone. Want to
know how much weight their vehicle could legal gross.I would get a
piece of paper and start asking questionsAxle configuration 5
axleTire width, - generally went with the standard 11 tireNumber of
tires per axle
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http://dotsc.ugpti.ndsu.nodak.edu/TWC/ND Truck Weight
Calculator
Plug the numbers from all our elements into the on-line truck
weight calculator, it will automatically produce legal axle
weights, gross vehicle weight allowed on a vehicle combination.
Can access and use the On-line truck weight calculator on your
Smartphone and I-pad or laptop
Go Live!!!!17
QUESTIONS?ND Local Technical Assistance
[email protected](701)328-9855
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