Infrastructure & Environment

Too Big for The Road

Massive trucks are tearing up fragile state highways. And more of them are out there every year.
by | July 2007
 

In central North Carolina, there's a lazy little stretch of state Highway 751 known as New Hill-Olive Chapel Road. It starts a few miles beyond the southwest suburbs of Raleigh, then winds past fields and trees, across cemeteries and over abandoned railway beds left from tobacco transport routes. But as you drive along, something else really catches your attention: It's full of potholes. As of last year, this 4-mile ribbon of two-lane highway was averaging one pothole or patched piece of asphalt for every 40 yards of road.

The primary reason for the condition of the road isn't age or weather or rush hour traffic. It's 18-wheelers. All day and into the night, weighty big-rigs are roaring down a secondary route that was never meant to carry them.

The extent of this phenomenon on Highway 751 and other North Carolina roads was detailed last year in an in-depth series of articles in the Raleigh News & Observer. But it's a scenario being played out across the country. A demand for cheap products and a national "just-in-time" delivery network has placed trucking companies under economic pressure to move heavier and heavier loads. The federal government mandates weight limits on the interstate system, but state legislatures often opt for more lenient weight rules, and so big carriers make their hauls on state highways and secondary roads.

Over the years many states, either through official policy or by taking no action at all, have actually encouraged freight trucks to carry heavier and heavier loads. The wear and tear being generated by heavy trucks is worsening maintenance needs at a time when states are already underfunding road maintenance by billions of dollars. With the nation's truck traffic expected to increase dramatically over the next decade, it's a problem that will only get worse. Some states have begun to enforce stricter weight limits, but in most, trucks continue to barrel through with increasingly heavy cargo.

PAYING THE PRICE

The nation's economy depends on trucking, but that method of shipment comes with a price. Engineers estimate that a fully loaded truck--a five-axle rig weighing 80,000 pounds, the interstate maximum--causes more damage to a highway than 5,000 cars. Some road planners say that the toll is even higher, that it would take close to 10,000 cars to equal the damage caused by one heavy truck. When the trucks are overloaded, as quite a few of them are, the damage is exponentially worse. Increasing a truck's weight to 90,000 pounds results in a 42 percent increase in road wear. Pavement designed to last 20 years wears out in seven.

"If you have to treat a road in five years instead of eight, or in eight years instead of 12, there's a real cost impact," says Judith Corley-Lay, the chief pavement management engineer for North Carolina's transportation department. At the request of state lawmakers, Corley-Lay recently analyzed truck traffic in the state to determine the cost of overweight trucks. What she found was startling: Heavy trucks are costing the state an extra $78 million per year. And that figure is really just a rough estimate, based on average road types and some guesswork to fill in gaps in traffic data.

The impact of these trucks is most dramatic in states that have allowed certain industries--coal, for example, or logging or steel--to use trucks loaded beyond even the state weight limits. In North Carolina, lawmakers have approved 10 measures in the past 13 years that allow heavier trucks on the state's secondary roadways, according to the News & Observer. But that's not unusual. More than 40 states permit some trucks to carry loads in excess of the 80,000-pound interstate limit. And legislators are under constant pressure to extend weight-limit permits to more categories of vehicles. "Every legislative session, some industry goes to the legislature and asks for an exemption," says Corley-Lay. "Every one of those exemptions means the trucks on the road are heavier."

Right now, 34 percent of the nation's roadways have been estimated to be in poor or mediocre condition by the Federal Highway Administration, and nearly one-third of the country's bridges are structurally deficient. It would take upwards of $200 billion this year simply to maintain the current state of the nation's roads; actually improving them would take billions more. Those challenges will grow much more difficult if, as has been predicted, the total freight carried in the United States increases from 13.2 billion tons in 2003 to 17.4 billion by 2015. States will likely find themselves under growing pressure from trucking companies seeking to haul more goods and bigger loads.

COPING WITH COAL

Industry pressure certainly played a role in West Virginia a few years ago, when lawmakers were considering whether to raise weight limits there. Coal-truck owners foretold nothing short of the collapse of the state's coal industry if legislators failed to raise the limit. A bill to establish an 80,000-pound maximum--and raise fines for violating it--was killed in 2002. The following year, the state passed a law that veered sharply in the other direction. It raised the allowable cargo weight to 120,000 pounds, on almost 2,000 miles of road in 15 southern West Virginia counties. In addition, the new law made it legal for 80,000-pound vehicles to travel on any road in the state, including many smaller roads that had never seen loads of that size before.

Neighboring Kentucky has taken a somewhat less permissive approach to trucking. To be sure, the state continues to be generous to coal trucks. Since 1986, coal freighters in Kentucky have been permitted to carry as much as 46,000 pounds of cargo over the 80,000-pound limit. But some coal trucks were exceeding even the higher ceiling, and in 2004, the state launched a crackdown on overloaded coal trucks, which seems to be holding more of them to the law. Last year, despite heavy lobbying from truckers and shippers, legislators defeated a bill that would have extended the coal weight-exemption to other industries, including gravel, sand, oil and natural gas. This January, state transportation officials closed a little-known loophole in the coal- exemption law that had allowed trucks to carry extra weight by adding extra axles.

Many states continue to see a competitive financial advantage in allowing the heavier vehicles, says Mantill Williams, director of public affairs for the American Automobile Association, which opposes any increases over the federal limit. "Part of it is economics. Trucking lobbyists usually present a very strong economic argument that exporting a certain product is good for a state's economy. The trucking industry in general is very well funded and well connected, and they can usually outman any type of opposing effort."

SOFTER FOOTPRINT?

Regardless of how strong the trucking industry's lobby is, some of its points do make sense. Allow trucks to carry more weight, the argument goes, and you'll cut down the overall number of trucks on the road. Fewer trucks means less fuel consumption, less traffic congestion and less danger to other drivers. And it might even mean less damage to the roads. That's the argument of groups such as Americans for Safe and Efficient Transportation, a coalition representing truck companies and freight shippers. In an effort to increase "truck productivity," ASET is pushing for a national across- the-board increase of truck weight limits. The group advocates raising the current maximum--80,000 pounds on five axles--to 97,000 pounds spread over six axles.

Those parameters would put the United States on par with higher weight limits in Mexico, Canada and Europe, says ASET executive director Jake Jacoby. "There's this knee-jerk reaction of, 'I don't want a truck to be bigger. I don't want it to be heavier,'" he says. "I understand that. But when you actually look at the data, these trucks would do less damage to roads. You're actually creating a softer footprint across the truck by adding a sixth axle. The pavement damage will go down." States have been painted into a corner, says Jacoby, because they can increase limits only on roads that have trouble handling much extra weight. By increasing the national limit to 97,000 pounds, the heavier trucks could travel on interstates. "The biggest winners would be the states," he says. "They would save a ton."

Road engineers aren't convinced. They say a higher national weight limit would move some truck traffic to interstates, but many heavy trucks would remain on state roads--surfaces that weren't made to handle 80,000 pounds, much less 97,000. Then there's the question of how feasible it might be for many trucking companies to change their entire fleets over to six-axle vehicles.

But ultimately, the issue isn't whether states or the national government should or shouldn't create a specific weight limit. It's that officials at all levels must recognize that changing the rules has an inevitable impact on the cost of maintaining infrastructure. "It may be that it is time to raise the limit," says Judith Corley- Lay. "I don't know. And as long as we can establish that link between economic benefit and the cost of maintenance and repair, then there's no problem with increasing the weight limit." Still, she says, states' track records with funding maintenance in general aren't very good. "Road maintenance has never been the glamour budget item."

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