A test patch of pavement at the UC Pavement Research Center.

If you’ve driven around California lately, you might not be surprised to hear that the state’s roads and highways aren’t in great shape. A third of Bay Area roads are in poor condition and funding is dwindling on the state and federal level. That’s something Congress is discussing in Washington this week.

Meanwhile, researchers at two University of California campuses are trying to find ways to stretch those sparse dollars by making pavement quieter, greener and more durable.

Saving the life of roads

John Harvey of the UC Pavement Research Center is a sort of pavement doctor. "A pothole is when you put the electric paddles [to it]. The pavement is dead. You should never get to a pothole." You can probably guess what he talks about on long car trips. "Actually I’ve had people threaten to kick me out of the car."

The Heavy Vehicle Simulator in action at UC Davis

At UC Davis’s pavement testing facility, a huge machine is rolling a truck tire over a patch of asphalt. "It goes back and forth," says Harvey. "We’re probably looking at 20, 22,000 repetitions a day."

This machine simulates years of traffic in just weeks or months, which shows whether a pavement will last or fall apart – like the rutted test patch Harvey shows me nearby. "There’s all kind of cracks all over it and that is a structural failure." Roads fail because of repeated stress, especially from heavy-duty vehicles. "We only really design for truck traffic. You don’t even count the cars. They’re irrelevant."

If a road’s first enemy is trucks, its second is weather. Temperature changes from night to day, or summer to winter, cause roads to curl. And just like a paperclip, if you bend it enough, it breaks. "You get enough cracking, the cracks connect up. And so the piece is just sitting in there with no connection and it pops out under traffic." Cities often fill potholes as a stop-gap, but Harvey says it’s a temporary fix. "Maximum life of a pothole repair: one year."

Of course, the hurdle to fixing roads is cost. In 2009, Caltrans estimated that it needed more than six billion dollars to repair state highways. With the state budget in trouble, it got 1.5 billion.

Federal Aid Highway Act of 1956

Samples of asphalt being tested at UC Davis.

Back in the 1950s, road funding was plentiful. Car sales skyrocketed after World War II, which led Congress to pass the Highway Act, providing 51 billion dollars to be spent on highway construction. Around the same time, the Pavement Research Center was founded at UC Berkeley, just as engineering professor Carl Monismith arrived on campus. He says with the building boom, the state and federal government needed funding to maintain the roads. So, they set up gas taxes. "The California tax in 1963 was 11 cents. And that bought a lot. It’s probably 18 cents now at the most."

Gas tax revenue has also fallen as cars have become more fuel efficient. That’s led analysts to predict that the federal Highway Trust Fund will be bankrupt by 2014. Monismith says many cities are already behind on maintaining their roads, so it’s tough to build new durable roads, which are more expensive. "The Roman roads have lasted, what, twenty-some hundred years. But we couldn’t build them like that today."

The good news is – given the country spends an estimated 100 billion dollars a year on roads, even small improvements make a big difference.

Quieter pavement

Researchers use the microphones on this “noise car” to measure the sound coming from the tires.

In a garage at UC Davis, John Harvey shows me what they use to test some of those improvements. This "noise car" is a Ford Escape hybrid with a large contraption on the back bumper. Harvey says, "These are directional microphones. So the idea is to screen out everything but the noise coming from the tire-pavement interface."

You probably know the sound of the wooshing of a freeway. At high speeds, that noise is mostly coming from the pavement. "The tire is squeezing air out from under it continuously and that’s the hissing sound." The microphones on this car are just inches from the ground, so Harvey and his team can record newly designed quieter pavements, like sections of concrete installed on I-5 in Sacramento. "We’re designing the pavement so the surface is porous and the air can be squeezed out from the tire and actually squeezed down into the pavement and that drops the noise considerably."

Freeway noise is mostly controlled with sound walls in California, but Harvey says they’re often more expensive than building the road itself. Some next-generation pavements will also save money for consumers – since roads affect how much fuel a car uses. "You’re consuming energy in your shock absorber. And your tires are actually consuming energy. They’re interacting with the surface of the road." The bumpier the road, the more work your car has to do.

"When you smooth a road, you can get two to five percent improvement in fuel economy, depending on the current roughness." And since that affects all the cars on the road, Harvey says it’s a way to cut greenhouse gas emissions under California’s landmark climate change law. Cleaner car regulations will undoubtedly make up the bulk of those cuts, but Harvey hopes that pavement will also get its due.

The California Air Resources Board is expected to vote on a new diesel-emissions regulation when the board meets on December 11 and 12 in Sacramento. As Dan Sperling, head of the Institute for Transportation Studies at UC Davis, explains in this clip, diesel trucks haven't been regulated the same way cars have been.

It would require all trucks on California roads to meet the lower 2010 emissions standards. The cost to retrofit a diesel truck could run anywhere from $10,000 to $25,000 per truck. There are roughly a million diesel trucks driving through the state – but not all of them are going to get the retrofit.

About half of the trucks traveling through California are from out of state. And almost all of those are long-distance freight trucks, which drive so many miles that they only last about three years – so most of the out-of-state trucks will meet 2010 standards in time.

That leaves about half-a-million California trucks, and of those, only about 200,000 are estimated to need retrofitting. From the truckers' point of view, that's still a tough haul in today's economy. Here's Bob Ramorino, President of Road Star Trucking in Hayward and head of the California Trucking Association, discussing how the new regulations could affect his business.

Overall, the expected cost is about $5.5 billion. About $1 billion of bond money will be available to make that transition easier for truckers.

And not just for truckers. Diesel buses will need to meet the requirement, as well. And blood centers are concerned about retrofitting their bloodmobiles.

If retrofitting really old diesel trucks doesn't quite make financial sense – that is, if the cost of retrofitting isn't worth the mileage left in some old diesel trucks — some truckers have the choice of junking those trucks and springing for new ones. But for bloodmobiles, with their specialized and complicated and expensive layouts, buying new could be financially crippling.

There's one more number to compare to all the others. According to the Air Resources Board, California loses about $40 billion a year due to lost job time and illnesses attributable to diesel exhaust. In the clip above, Dr. Tom Dailey, chief of pulmonary medicine at Kaiser Permanente, Santa Clara talks about some of those health dangers.

Listen to the Get the Soot Out radio report online.

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