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State leaders push for higher truck load limits

MnDOT wants to let big trucks haul larger loads, but wear on bridges and roads is an issue.

By Dan Browning, Star Tribune

Last update: August 27, 2007 – 10:53 PM

State transportation leaders want to ease restrictions on the weight trucks carry on Minnesota roads, despite concerns that heavier loads may shorten the lifespan of bridges.

Trucks moving certain farm and timber products already have permission to carry extra loads, thanks to recent state laws passed at the request of those industries.

Advocates for a broader change to the state's weight restriction argue that the step would make hauling more efficient and help them compete with the Dakotas and Canada, which allow heavier trucks.

Opponents contend big trucks are a safety hazard and will wear out bridges faster. And in the aftermath of the Interstate 35W bridge collapse, some lawmakers say potential damage to bridges -- and who pays for it -- must be a part of the discussion.

But the need for more efficient shipping methods is growing.

The North American Free Trade Agreement has dramatically increased international trade. "Just-in-time delivery" methods demanded by big-box retailers have turned highways into rolling warehouses. And now, Midwestern states such as Minnesota are seeking better ways to move corn to ethanol distilleries.

Gov. Tim Pawlenty's administration met resistance when it proposed a general elevation of truck weight restrictions in 2006. So in this year's session, MnDOT put the proposal on hold and lent its support to industries pushing their own legislation as long as they followed agency recommendations, said Betsy Parker, MnDOT's government affairs director. They include adding axles to spread the weight over more tires, and posting restrictions or closures on bridges that can't bear heavier loads.

MnDOT still backs higher weight restrictions because of a 2006 study that concluded they would make deliveries more cost-efficient and may even do less damage to pavement, according to Cecil Selness, the agency's director of freight and commercial vehicle operations. "The other part that we looked at is, if you can carry more per truck you can reduce overall the amount of trucks that are in the traffic mix, and that has a positive effect," Selness said.

U.S. Rep. Jim Oberstar, a Minnesota Democrat and chairman of the House Transportation and Infrastructure Committee, said in a recent interview that MnDOT's cost-benefit claims are unproven. He said he has been fighting proposals to allow heavier trucks on interstates for many years because of safety concerns and because the shipping industry has not been willing to pay for the damage it would do.

"And one of the consequences of increased weight is the effect on bridges and road surfaces," Oberstar said. "If they deteriorate faster, then someone has to pay for that."

The nonpartisan Congressional Research Service said in a 2005 report that growing reliance on trucks to move grain has led to increasing concerns with wear and tear on rural roads and bridges.

A MnDOT study recommends allowing heavier trucks on state and some county roads even though it would cost about $2.7 million a year in additional bridge costs. MnDOT's Selness said he assumes the expense would be paid like any other highway project; the study didn't address funding.

Steven Frank, president and CEO of the American Automobile Association of Minneapolis, said it wasn't much of a study at all; he called it an "advocacy project."The foregone conclusion was that truck weights would be increased, and it was just a matter of determining the best way to get it done," Frank said.

Study recommendations

The "Minnesota Truck Size and Weight Project" study, conducted for MnDOT by Cambridge Systematics Inc. of Bethesda, Md., offered a number of recommendations, including an expansion of the state's system of heavy-duty roadways and more "flexibility" for weight limits and vehicle configurations.

The report recommends increasing truck weights from the current 80,000 pound cap to between 90,000 and 108,000 pounds, depending on the number of axles and how they are configured.

Nearly everyone seems to agree that regardless of their effect on pavement, heavier trucks wear out bridges faster.

A 2003 study by the University of Minnesota concluded, "Any increase in legal truck weight would shorten the time for repair or replacement of many bridges."

Most modern bridges could tolerate a 20 percent increase in truck weight with no reduction in lifespan, the study says, but that strain could shorten the life of older steel bridges by up to 42 percent. "Unfortunately, most Minnesota steel girder bridges were designed before fatigue-design specifications were improved in the 1970s and 1980s," it adds.

Selness acknowledged that MnDOT's truck weight proposals would accelerate bridge deterioration. But the heavier trucks would only be allowed on spans MnDOT's engineers deem adequate, he said.

The truck-weight study concluded that heavier trucks and changes to seasonal road restrictions would cost about $8.2 million a year in additional pavement and bridge expenses. But it also concluded that the changes would net $45.38 million a year in overall benefits -- including a savings of $2.47 million from added safety.

Frank, the AAA executive, said MnDOT's study failed to adequately consider the amount of traffic that would be diverted from interstates.

"Heavy trucks on two-lane roads are two times more dangerous than they are on the interstate highways," he said.

A MnDOT study of freight transportation needs in 13 of the state's southwestern counties made similar points.

"Safety is an increasing concern on rural roadways," where 70 percent of Minnesota's crash fatalities happen, according to a draft report provided to the Star Tribune.

Some haulers OK with limits

Not all haulers want to increase payload caps. Representatives of the Aggregate & Ready Mix Association of Minnesota and the Minnesota Trucking Association said they are satisfied with current limits. But others say heavier loads will help Minnesota compete.

Wayne Brandt, executive vice president of Minnesota Forest Industries and Minnesota Timber Producers Association, said it got a bill passed in 2004 to allow 90,000-pound loads of timber to be hauled in six-axle trucks from the woods to the mills. Now the industry wants flexibility to haul finished paper products between regional distribution hubs.

Brandt said that the Minnesota mill and forest product associations have supported fuel tax increases for some time to pay for better roads and bridges. "We have no interest in wrecking the roads," he said. "We want them to be safe."

Bruce Kleven, a lobbyist for the ag industry, said heavier loads would reduce the number of trips for farmers by 10 to 12 percent, which produces less pollution and higher profits. "I know this bill is probably more sensitive now with the collapse," he said. "I want to be clear that the farm groups were never in favor of doing something to increase wear and tear on the roads and bridges."

Parker, MnDOT's legislative liaison, said she would not know until the fall whether the Pawlenty administration would push an across-the-board increase in truck weight limits next year.

State Rep. Loren Solberg, chair of the Ways and Means Committee, said he agreed to sponsor MnDOT's bill to increase truck weights this year but at the agency's request, did not take any action on it. "They wanted to have some discussion on it," he said. "I guess this [bridge collapse] incident will really bring out the discussion."

State Sen. Dick Day, a Republican from Owatonna who sits on the Transportation Committee, said his colleagues have passed higher load limits in recent years for sugar beets, carrots and some forest products, so it only seems fair to give corn farmers in his district similar breaks. But not at any cost.

"If someone could say that ...over a long period of time this is going to make a weaker structure, either in bridges or roadways, we'd all be pretty much fools if we continued to do that and not lower weights or change what we're doing," Day said.

Dan Browning • 612-673-4493

Dan Browning • dbrowning@startribune.com

Editorial: Truck weights need better enforcement

Bridges, roads suffer when trucks are too heavy.

Published: September 21, 2007

Nothing beats up roads -- or bridges -- like heavy trucks. That's why wise legislators were already saying no in 2006 to proposals from the Minnesota Department of Transportation and business interests to allow heavier trucks on state roadways. They already knew then that without a plan to shore up the state's aging bridges, heavier trucks would only create a higher risk of catastrophe.

Today, Minnesotans know two things that those legislators didn't know then. One, they know that bridges indeed can fall, with deadly consequences. And two -- thanks to the reporting of the Star Tribune's Dan Browning -- they know that Minnesota is just barely enforcing the truck weight limits it has now.

It isn't known yet whether those two things are connected. Federal officials analyzing the twisted wreckage of the Interstate 35W bridge have said that they consider structural fatigue, the result of excessive weight loads, a possible culprit for its collapse.

But legislators should know enough now to vow to address the truck weight issue, as they consider how to improve Minnesota's transportation infrastructure. They were right in 2006 to refuse to increase weight limits before raising revenue to pay for road and bridge upgrades. In light of Browning's report, they should add this resolution: Heavier trucks should not be allowed until MnDOT devises and the Legislature funds a workable system for enforcing weight limits.

The weight-enforcement regime Minnesota has now simply doesn't work. Spending cuts have reduced hours and staffing at weigh stations by half or more around the state. Metro traffic congestion has made stopping trucks nearly impossible. Haulers find the state's complicated rules hard to understand. They face increasing financial incentives to cheat, and a shrinking chance that they'll get caught. It's easy to see why citations for overweight trucks in Minnesota have dropped 21 percent since 2002, even as truck traffic volume has climbed.

The extent of the problems with the state's bridges and with truck-weight enforcement may be new information to many Minnesotans. But it is not news to MnDOT. That's why it's baffling that the agency would appeal to the Legislature in 2006 to allow heavier trucks on state highways, before first addressing bridge and enforcement inadequacies.

Perhaps MnDOT's focus was on the prospect of requiring big trucks to have more axles, to distribute their weight more evenly; that proviso would ease the impact on road surfaces. But a 2003 study by the University of Minnesota advised MnDOT that bridges are another matter. "Any increase in legal truck weight would shorten the time for repair or replacement of many bridges," the report said.

In Minnesota, of all places, that warning deserves heed.

September 21, 2007

Dear Editor:

I am extremely concerned about the editorial in the Friday edition of the Star Tribune regarding truck weights. I am even more perplexed as to how you can make these statements without providing any supporting data or documentation.

The article clearly reflects a jumping to wild conclusions that are effectively erroneous! You are incorrect on several points; each of which I would like to address.

• First of all, the Legislature NEVER voted on any Mn/DOT proposal to increase truck weights. While a bill was introduced, legislators never said “yes” or “no”.

• Second, the Star Tribune implies that heavy trucks caused the 35W bridge to collapse; yet there is not one report or governmental agency that has cited this as a cause.

• Third, bridges are engineered to handle legal weights as well as a certain number of legal, permitted, overweight loads.

• Fourth, the paper has implied that trucking is somehow not paying its fair share. That is simply not true and once again, you have failed to validate with any supporting data or documentation. Trucks make up four percent of the registered vehicles in the state, and account for eight percent of the vehicle miles driven, but pay a whooping thirty-five percent of all state and federal taxes and fees collected. Those numbers are documented statistics and validate the reality that you have failed to mention.

Under no circumstances would we ever put our name on each of our trucks and trailers unless we were certain that they are running safely and within legal weight parameters. To do anything less is just plain stupid.

Jack Shawn

Chair, Minnesota Trucking Association

www.mntruck.org

Heavier vehicles take toll on roads

Rapidly increasing weight load is ‘beating up’ nation’s highways, bridges

The Associated Press

Updated: 6:49 p.m. ET Aug 10, 2007

WASHINGTON - Just like Americans themselves, the nation’s roads and bridges are carrying much more weight today.

Added to an aging and deteriorating highway system, that means more safety problems, delays and repair costs for drivers, experts said.

In just a decade, from 1995 to 2005, the weight load on urban highways increased by half. Since 1970, the weight carried on rural highways has gone up nearly 7½ times, according to Federal Highway Administration statistics.

And it’s not just more traffic. It’s the heavier trucks.

“The number of trucks and the number of heavy trucks have gone up dramatically since 1965,” said Mark Hallenbeck, director of the Washington State Transportation Center at the University of Washington.

“The warehouses that used to fill up are now driving down the road next to you,” he said.

And that, he added, is “beating up” American roads.

'We need to ask the questions'
The number of tractor-trailer truck miles driven on American roadways has well more than doubled to more than 145 billion miles a year since 1980, increasing faster than the rate of smaller trucks or cars, according to federal statistics.

“If we’re doubling our loads, we need to look at our infrastructure to be able to carry that,” said James Garrett, co-director of the Center for Sensed Critical Infrastructure Research at Carnegie Mellon University. “We need to ask the questions.”

That’s why some engineering experts speculate that the wear and tear over the years of heavier loads could be one of the factors that triggered the collapse of the interstate bridge in Minneapolis last week.

More weight wouldn’t be a problem if the highway system was regularly and adequately maintained because well-kept roads and bridges can handle the added weight, said University of Texas civil engineer professor C. Michael Walton.

The American Society of Civil Engineers gave the nation’s roads a “D” grade and the bridges a “C” grade in 2005.

Trucks singled out
One of the factors was the increased weight, said John E. Durrant, the society’s managing director of engineering programs. Extra weight from increased truck traffic over time will push a bridge that’s already susceptible to fatigue “to reach the end of it’s life sooner,” he said.

Clayton Boyce, a spokesman for the American Trucking Association, said it is unfair to single out trucks.

“Yes, it is an increase in traffic and, yes, it’s an increase in cumulative weight, but there has been a similar increase in the number of automobiles,” Boyce said.

Mark Berndt, chairman of the truck weight committee for the National Academies of Sciences’ Transportation Research Board, said the United States has some of the strictest weight limits of any industrialized nations, limiting trucks on the federal interstate system to 80,000 pounds, a limit that has been around for decades. State roads, however, can allow heavier trucks.

Trucks in Europe can go up to 97,000 pounds and Canada and Mexico allow up to 100,000 pounds, he said.

“There’s no doubt that the truck has more of an impact on a bridge than a car, but it’s really being driven by the nature of our economy,” said Berndt. “Certainly truck traffic has increased far more than anyone predicted. That’s been one of the big issues in transportation in the last 10 to 15 years.”

Bigger, heavier loads
Berndt, who recently studied rural Minnesota truck traffic, said that mostly farmers who used to drive small trucks are now using bigger and heavier tractor trailers.

America is gaining a great economic advantage by using more and heavier trucks, said Walton. But the next step is to take just part of the cost savings and translate that into fixing roads and bridges, he said.

Boyce said his trucking group supports an increase in gasoline tax as long as it is targeted to fixing roads.

“We’ve gone too long really making just incremental improvements to the interstate program. We haven’t kept up with maintenance,” he said.

The problem boils down to basic engineering. When engineers design bridges and roads there are two factors to balance: load, the force weighing on the structure, and resistance, the ability to withstand that force.

What’s happening is that loads are increasing while time, weather and fatigue weakens resistance.

Bridge problem is pure weight
Heavier loads cause different problems for bridges and roadways. For bridges the problem is pure weight.

Bridges are designed to withstand up to twice as much as the anticipated weight loads, said W. Gene Corley, a forensic engineer with the Skokie, Ill.-based engineering firm CTL Group.

But when a bridges can’t handle the weight, states put up load limits, restrict the size of trucks using them.

A 2006 Department of Transportation Inspector General study checked out 43 bridges in Massachusetts, New York and Texas and found that at least 12 of them allowed vehicles to cross that were heavier than the bridge’s maximum weight limit. And 11 of those did not have the required posting signs.

The collapsed Minnesota bridge had no weight limits but was categorized as structurally deficient, one of over 73,000 U.S. bridges with that designation last year. The federal government usually places bridges that have weight limits on the functionally obsolete list, which includes another more than 80,000 bridges.