The Federal Bridge Gross Weight Formula (also known as Bridge Formula B and the Federal Bridge Formula) is a mathematical formula in use in the United States by truck drivers and Department of Transportation (DOT) officials to determine the appropriate maximum gross weight for a commercial motor vehicle (CMV) based on axle number and spacing. The formula is part of federal weight and size regulations regarding interstate commercial traffic (intrastate traffic is subject to state limits). The formula is necessary to prevent heavy vehicles from damaging roads and bridges. CMVs are most often tractor-trailers or buses, but the formula is of most interest to truck drivers due to the heavy loads their vehicles often carry.
Early 20th-century weight limits were enacted to protect dirt and gravel roads from damage caused by the solid wheels of heavy trucks. As time passed, truck weight limits focused primarily on gross weight limits (which had no prescribed limits on length). By 1974, bridges received special protection from increasing truck weight limits. The bridge formula law was enacted by the U.S. Congress to limit the weight-to-length ratio of heavy trucks, and to protect roads and bridges from the damage caused by the concentrated weight of shorter trucks. The formula effectively lowers the legal weight limit for shorter trucks, preventing them from causing premature deterioration of bridges and highway infrastructure.
Compliance with the law is checked when vehicles pass through a weigh station, often located at the borders between states or on the outskirts of major cities, where the vehicle may be weighed and measured. The one exception to the formula allows a standard five-axle semi-truck configuration to weigh the maximum legal gross weight. This exception was specifically requested by the American Trucking Associations to allow tank trucks to reach the maximum legal gross weight without violating the bridge formula law.
Read more about Federal Bridge Gross Weight Formula: History, Usage, Bridge Collapse, Formula Law, Exception, Issues, Bridge Formula Table
Famous quotes containing the words federal, bridge, gross, weight and/or formula:
“There are always those who are willing to surrender local self-government and turn over their affairs to some national authority in exchange for a payment of money out of the Federal Treasury. Whenever they find some abuse needs correction in their neighborhood, instead of applying the remedy themselves they seek to have a tribunal sent on from Washington to discharge their duties for them, regardless of the fact that in accepting such supervision they are bartering away their freedom.”
—Calvin Coolidge (1872–1933)
“I was at work that morning. Someone came riding like mad
Over the bridge and up the road—Farmer Rouf’s little lad.
Bareback he rode; he had no hat; he hardly stopped to say,
“Morgan’s men are coming, Frau, they’re galloping on this way.”
—Constance Fenimore Woolson (1840–1894)
“I am haunted by interrupted acts,
introspective as a leper, enchanted
by a repulsive clew,
a gross and fugitive movement of the limbs.
Is this the love that shook the lights to flame?”
—Muriel Rukeyser (1913–1980)
“I falter where I firmly trod,
And falling with my weight of cares
Upon the great world’s altar-stairs
That slope thro’ darkness up to God,”
—Alfred Tennyson (1809–1892)
“So, if we must give a general formula applicable to all kinds of soul, we must describe it as the first actuality [entelechy] of a natural organized body.”
—Aristotle (384–323 B.C.)