It's heavy trucks that wear out highways, but truckers pay a hefty price for use of the public roads, officials say.
"It is pretty well documented that trucks are responsible for most damage to road surfaces," says Raymond Forsyth, chief of the pavement laboratory of the California Department of Transportation in Sacramento.
"The next time you're on a four-lane highway, compare the outside lane where the trucks travel with the inside lane where there are only cars," he suggests. "The outside lane is likely to be very badly distressed, but the inside lane may be almost pristine."
45,000 Miles of Highway
There are about 45,000 miles of highway in the California road system. About one-third of that is freeway.
Even though trucks are responsible for most of the wear and tear, they account for only a fraction of the miles traveled. Of the 196 billion miles driven on California roads last year, only 7.2 billion, or 3.7%, were logged by trucks.
"Cars aren't even considered in designing a pavement," Forsyth says. "Passenger vehicles add almost nothing to the equation."
The most striking example of that, he says, is the Arroyo Seco Parkway section of the Pasadena Freeway, where trucks are restricted.
"Normally, such a road surface (with trucks) would be expected to last 12 to 14 years," he says. "It has had a service life of 35 years without need for major rehabilitation."
More Axles Help
Damage to roads isn't caused by the overall weight of trucks, Forsyth says. Rather, it's how the weight is distributed.
"The more axles you have, the less weight is transferred to the pavement on each axle, and hence the less damage to the road," he says.
California law limits loads to 20,000 pounds per axle. Those who exceed it and get caught face fines of thousands of dollars.
The state spends about $510 million a year on highway rehabilitation (major reconstructive surgery) and maintenance (everything else, including patching potholes, clearing snow and litter, landscaping and fixing roadside rest stops).
Of that, about $172 million is spent on road surfaces alone--$110 million for rehabilitation and $62 million for maintenance.
Truckers pay the state $387 million a year in fuel taxes and commercial license fees.
Depending on how you look at it, that's either too much or too little.
It's 225% of the amount spent annually to repair road surfaces, but it's about 75% of the total when you include other items like snow clearing, litter pickup and landscaping.
Fuel taxes and commercial license fees are a major factor in making the truckers one of the most heavily taxed industries in the nation, with an average corporate tax rate of about 38%. That compares to the average for all companies of about 18%.