Rory Rhinesmith, PE

DTSD Deputy Administrator

• Equipment increasing in

size and weight

• Update statutory

definition of IoH

• Need to maintain roads

– balancing agriculture’s

need and town/county

responsibility

• Provide safe roads and

bridges for all

Overall Issue: No envelope vehicle

• Ag equipment inventory being used in Wisconsin is

extremely varied and has non-standard dimensions

and weights as compared to the commercial motor

vehicles that are used in the design of our

infrastructure.

3

Weather

Subgrade material properties

Pavement structures Most common structure types, from WISLR

3-inch CMA over 6-inch base

5-inch CMA over 12-inch base

3-inch HMA over 9-inch base

6-inch HMA over 18-inch base

Pavement structure material properties

IoH categories I, II, III and IV Axle weights (from Minnesota study)

Tire contact pressure (from Minnesota study)

40 different axle loadings

1 vehicle travel speed (10 mph)

Source: LRRB (MN)

• Similar straight trucks

• Same tank capacity

• One with regular radial ply dual tire configuration

• One with a flotation single tire configuration

“No significant benefits were observed between

flotation tires and radial tires in pavement responses.”

MN ROADS STUDY

• 14,050 bridges (over 20’ in length)

• 5217 State Owned (37%)

• 8833 Locally Owned (63%)

8

STATE 37%

COUNTY 22%

CITY/ VILLAGE

9%

TOWNSHIP 32%

<1%

Pavement and Structures

Equipment Analysis

Empty Configuration Loaded Configuration

Impact to Bridges

Impact to Pavements

Analysis to Evaluate

Impacts to Infrastructure

Compared to

Federal

Bridge

Formula

Three categories:

• Category A = Farm tractor

• Category B =

Effective- 4-24-14 11

• Self-propelled combine, forage harvester or self-

propelled fertilizer or pesticide application

equipment but not including manure application

equipment;

• towed tillage, planting, and cultivation equipment

and its towing power unit;

• or another self-propelled vehicle that directly

engages in harvesting farm products, directly

applies fertilizer, spray or seeds but not manure, or

distributes feed to livestock.

• Category C = A farm wagon, farm trailer, manure

trailer, or trailer adapted to be towed by or to tow or

pull, another implement of husbandry.

Weights GENERALLY increased by 15% for IoH and Ag CMV over the Federal

Bridge Formula (FBF).

Maximum GVW 92,000 lbs

Maximum Axle weight 23,000 lbs.

New IoH/Ag CMV Weight Table reflects necessary number of axles and

axle spacing

New IoH/Ag CMV weight allowances DO NOT apply on the Interstate

Highway System

EXEMPTIONS:

• No axle weight limits on empty potato harvester.

• Category B

Effective- 04-23-14

12

2/17/2015 13

What we used from the MnROAD IoH Study:

Farm equipment classification

Tire pressure - and more importantly

contact pressure

Axle weights and measurements

Loaded and unloaded weights

Pavement performance