How Much Weight Matters?

Enforcement Vs. Reality

By Tom Kelley

Any veteran of driving Michigan’s highways and surface roads can attest to the fact that extremely heavy (120,000 pounds and up) trucks can adversely affect roads and bridges, especially those that are out of date or built with substandard materials. But, this presents the obvious

question: Just how heavy is heavy?

If you’re looking at the letter of the law, being as little as 1,001 pounds overweight can land you in trouble in some states. On the other hand, if you’re looking at the spirit of the law, in most circumstances there is no significant impact caused by as much as 10,000 pounds of excess weight. Unfortunately, most enforcement situations tend to gravitate toward the letter of the law, rather than the spirit of the law, so the accuracy of your truck’s weight becomes fairly important.

Perhaps the most notorious of weight enforcement scenarios involves the use of portable scales. Even when properly calibrated and set up on perfectly level ground, the typical 1,600-pound margin of error on a portable scale is well outside the 1,000-pound “grace” allowance for excess weight. When these scales are used on uneven ground, that 1,600-pound error can balloon dramatically. How many parking areas or road shoulders have you ever seen with a perfectly level 10′ x 150′ area?

So, just how many trucks are actually running overweight? According to the ATA, statistics for one year showed that 160 million trucks were stopped and weighed. In that same year, 600,000 citations were issued for trucks that were overweight. This says that trucks were in compliance with the weight laws 99.5% of the time. That one-half of one percent running overweight is a far cry from the “killer truck”

statistics often quoted by the various anti-truck lobbying groups that oppose efforts to raise the current weight limits.