Rolling Heavy

One day you decide you want to open a shipping company. You buy a truck, a trailer, find space to operate, line up your first customer and stock the truck as full as possible and head on down the road, right? Wrong. There are a number of issues and requirements that must be addressed first, one of them being weight.

Currently, the federal government limits the weight of commercial vehicles to 80,000 pounds on the federal interstate system, except for a few states who have received exceptions for up to 100,000 pounds. A number of groups are urging the government to increase weight limits on these roads nationwide. But why do we care about weight?

Weight has a surprising impact on nearly every facet of the transportation life cycle - from cost, to safety, to engineering.

Drift back to high school physics. Force, in its simplest definition, is that which causes an object to change its velocity, or speed. This is usually calculated by mass (weight of the object) multiplied by the acceleration, therefore, the more something weighs, the more force it requires to achieve the same acceleration. While the specific calculations needed to move these trucking trailers is best left to engineers, it is easy to see that increased weight means extra engine power and therefore, more fuel is required. The harder engines work, the more they consume and the more a fleet has to pay to feed them. Whether it is higher speed or added weight, small changes can have a big impact on the bottom line and fleets must balance increased fuel use with the increased efficiency of running heavier loads.

But how does additional weight and fuel impact safety? Well, that same equation that shows more weight takes more power to move also shows that more weight means more power required to stop. Often this stopping power equates to stopping distance. It's no new concept that the faster you drive the more time it takes to stop; the same is true with weight, the more weight behind you the longer the distance needed to slow down. This can have a profound impact in split-second situations where a tractor-trailer may need to reduce speed quickly for their own (and others?) safety.

What does this mean for engineering? Roads are designed to handle a certain amount of wear and tear created from volume of traffic, freezing and thawing, and yes, weight. The closer traffic weight gets to the designed maximum weight limits, the quicker a road breaks down. While an increase to maximum commercial weights can be changed with a simple signature of Congress, the amount of weight roads can handle is not so easily improved. And the impact increased weight would have on road design and maintenance costs must be considered before changes are made.

Recently though, the transportation sector has something to be excited about. The U.S. Department of Transportation will soon be teaming with state agencies to study what effects trucks running heavier than currently allowed have on safety. This is an integral step in properly analyzing the increase in weight so many fleets and industry groups are pushing for.

After all, knowledge is power, and we're not just saying that because we're data geeks either.

This entry was posted on April 30th, 2012 by jhubbard and is filed under Recent News & Updates.