How California measures ‘road smoothness’ and why it matters
Every time you pay more at California’s gas pumps to fill your tank, you’re feeling the price to fix the state’s roads.
But are you feeling the improvement?
California’s newly paved roads are built to standards of smoothness that are the strictest in the country. With that standard comes high costs that have surprised contractors, who are fighting for reimbursement and bitterly condemning a level of smooth they say no driver would ever notice.
At least one major contractor also contends the smooth pavement is dangerous, arguing that corrective measures he takes to hit the target actually shave features that are supposed to keep roads safe in wet weather.
The dispute, growing since standards were toughened four years ago, has been heightened by Caltrans’ launch of a decadelong construction program supported by a gas tax that took effect in November. Caltrans intends to reduce a deep transportation maintenance backlog that has caused clogged commutes and slowed commerce across the state.
If the department would be more flexible, contractors argue, taxpayer money would go further.
“Nearly every contract is being protested and in claim, resulting in issues of economic waste and more importantly, safety,” nine pavement companies wrote in a June letter to Caltrans Director Malcolm Dougherty that asked him to reconsider the rule.
It was the third in a series of testy letters to Caltrans executives from pavement companies arguing the department botched the rollout of its smoothness standard by foisting it on to contractors with little preparation.
They’re winning some of the claims, too, with independent evaluators calling the new standard “defective.”
So far, Caltrans is holding to its smoothness standard, arguing that its long-term benefits outweigh any short-term spike in construction costs.
“I want smooth pavement. I want a high quality product,” Dougherty said. “They’re asking me to relax my expectations so it’s not as smooth a ride. We haven’t been willing to do that.”
‘We weren’t even close’
California highways are among the worst in the country, hobbled by a maintenance backlog that Caltrans and local governments have been unable to address. The state’s highways regularly rank in the bottom tier for road condition in the Reason Foundation’s annual highway report.
In 2015, a Senate committee reported that 68 percent of California roads were in “poor” or “mediocre” condition. That report projected a $57 billion shortfall over a 10-year period for needed highway maintenance. The new gas tax is expected to raise about $15 billion for highway maintenance over the next decade.
In 2013, Caltrans made two big changes aimed at gradually improving ride quality for California drivers.
First, California joined most other states in measuring new pavement smoothness with a laser-based instrument known as an inertial profiler, replacing the manual method Caltrans had used since the 1940s.
The profiler helped Caltrans measure road smoothness in a common system called the international roughness index. Smooth roads get lower scores. It estimates in inches how much a vehicle suspension system would move up and down over a mile because of imperfections in a road’s surface, such as bumps or small divots.
Second, using the new system of measurement, Caltrans handed contractors the toughest road smoothness standard in the country. The smooth roads, Caltrans argued, would pay for themselves over time because they’re known to last longer than rougher ones, and they may improve gas mileage enough to reduce greenhouse gas emissions.
Caltrans directed contractors to pave to mean roughness index 60, meaning the laser profiler should not capture more than 60 inches of up-and-down movement over a mile of road.
Caltrans is alone in requiring contractors to smooth out stretches of road that don’t meet that target. Other states tend to penalize contractors for rougher patches, but do not require corrections unless the profiler captures 90 inches of up-and-down movement over a mile.
Four years ago, California contractors began bidding work with no idea what the new rule would cost them.
“We went out and paved, and we weren’t even close. We were just kind of dumbfounded,” said Armando Garcia, a former Caltrans construction executive who now works for San Diego-based contractor Coffman Specialties.
‘These roads are going to be glass’
California paver Jim Coffman worries that the $114 million highway renovation he finished last year in San Bernardino County made the drive from San Diego to Las Vegas less safe.
Coffman sent his best crews to the job at Cajon Pass at 4,200 feet above sea level on Interstate 15, and finished the work ahead of schedule.
Or so he thought.
The road did not meet Caltrans’ smoothness standard. It was especially rough on steep grades.
The remedy for rough pavement usually involves smoothing concrete with a diamond-bladed grinder. It’s a safe fix that state transportation departments use to rehabilitate old roads, extending their usefulness until the road can be replaced.
Coffman, though, worried that grinding long stretches of Cajon Pass reduced the highway’s wet-weather safety features.
One is a series of thin grooves in concrete that whisk water away from tires during storms. Another is macrotexture, intentionally rough features designed to enhance traction.
After grinding, Coffman’s newer projects showed an almost polished surface.
“This road needs as much texture as you can get,” Garcia said on a foggy November morning at Cajon Pass as heavy traffic sped downhill toward Riverside. “People just fly through this. It’s way too slick.”
He and Coffman point to recommendations from the National Academy of Sciences, as well as Caltrans’ own standards, that indicate roads are safer in wet weather when they have features to induce friction.
“It’s certainly the case that the smoother surface you have, the less easy it would be stop and slow down in wet weather,” said Ashlie Martini, a professor of mechanical engineering at UC Merced.
Other pavers The Bee contacted would not go as far as Coffman in calling extensive grinding unsafe. Caltrans conducts skid tests on new roads, and refuses to open them if they lack friction.
Coffman’s project passed those tests.
Other experts report that grinding does not necessarily decrease friction. A 2013 study by the University of California Pavement Research Center, for instance, concluded that grinding does not prevent a road from meeting skid-resistance standards.
“It is not impossible that on a particular project there could be a problem. In general, there would not be. It would be an anomaly for there to be a problem,” said Shelley Stoffels, a civil engineering professor at Penn State University.
California Highway Patrol records show that the number of wet-weather injury accidents increased at Cajon Pass last year to their highest level in five years. It’s hard to draw a conclusion from the records, however, because of last winter’s heavy rains.
Coffman fears the highway’s friction characteristics will wear down quickly, compelling the state to revisit the project within a few years to restore features for wet-weather safety.
“Those roads are going to be glass in five years,” he said.
What does it cost?
Grinding a road to smooth out rough spots costs enough money for contractors to lose their profits on certain projects.
“There are two types of contractors: those who have lost money because of the new smoothness requirements, and those who will,” an asphalt contractor joked at a 2016 conference, according to a California Asphalt Pavement Association newsletter.
Contractors have been pressing Caltrans to pay them for the additional work.
Sacramento’s Teichert Construction, for instance, said it spent $586,000 on grinding for a $116 million project in San Bernardino County.
Flatiron Construction spent $55,000 on an $11 million project in San Diego.
Coffman spent $650,000 grinding pavement on what was supposed to be a $49 million project along the Mexican border.
Dispute resolution boards – independent panels that weigh contractor complaints – sided with the pavers in each of those cases. The decisions are not binding. They’re a step along the way to court-ordered arbitration.
Boards in the Flatiron and Teichert claims called the smoothness standard “defective,” according to documents obtained by The Bee. In Coffman’s, the board said the grinding Caltrans ordered constituted “economic waste” because it did not benefit the public.
“It is unnecessary. We should grind when it’s necessary, not just because people are forcing” a contract specification, said Larry Scofield, a former pavement manager for the Arizona Department of Transportation who now is director of research for the International Grinding and Grooving Association. His organization advocates for grinding companies.
Coffman in a letter to Caltrans said grinding on his Cajon Pass project pushed up his expenses by $3 million. He’s preparing a claim.
It’s unclear how many claims Caltrans has received because of the smoothness standard. The department does not track that kind of information and assembling it would take months, the department said.
Caltrans contends the contractors should have anticipated the expenses.
“They knew the requirement when they bid on the job. They knew what the specifications were,” Dougherty said.
Caltrans released two dispute resolution board decisions that supported the department’s smoothness standard. One sided with the state, noting that most of a contractor’s work hit the standard, which the board said proved that the target was achievable. It further criticized the contractor for bidding on a project it didn’t understand.
Contractors won’t go out of business because of the standard. Instead, they’ll raise the price of their work.
“We all have a hard time with the new standard. We’re all struggling. We’re all spending a lot of money, and we’re just going to put it in future bids,” said George Butorovich, pavement manager at Flatiron Construction.
Why weren’t they ready?
Contractors say Caltrans did not make a good-faith effort to test its smoothness standard or to give them opportunities to try it before bidding.
“None of that happened,” said Scofield of the grinding association. “They dropped the hatchet overnight.”
The state’s asphalt pavement association also faulted Caltrans for putting a standard in place before contractors understood it.
“Our feeling is that doing something new and just seeing how many claims you get is not a good way of getting new standards and specifications,” said its executive director, Russ Snyder.
Caltrans counters that it began experimenting with laser-based smoothness measurements in 1998, and that it signaled its shift to that device with a series of forums between 2010 and 2012.
Caltrans also picked 21 pilot projects between 2010 and 2012 to test the equipment.
In recent communications, Caltrans told contractors that the projects were intended merely to help pavers understand how to use inertial profilers. They were not designed to gauge whether contractors realistically could achieve the smoothness target.
Asphalt and concrete contractors have persistently asked Caltrans to disclose data it obtained from the pilot projects, but the department has not released information on the jobs.
Last year, a group of pavers conducted their own smoothness tests on some of the original pilot projects. Their smoothness scores varied widely, from a mean roughness index of 30 inches per mile to 170 inches. One in Sacramento on Interstate 80 averaged 95 to 105 inches.
“The data indicates the current specification cannot be achieved without substantial or continuous grinding,” the Southwest Concrete Pavement Association wrote to Dougherty.
Paying for smooth
A commuter in a sedan probably will not notice a difference between new pavement at mean roughness 60 and mean roughness 80, pavement engineers say.
The smoother roads might still be valuable to taxpayers, however. A road built smoothly will more evenly distribute vehicle weight and be less prone to wear and tear, which is especially important when accounting for the impact of heavy trucks.
“Even if the drivers don’t feel the difference, the pavement feels the difference,” Stoffels of Penn State said.
This month, industry representatives and Caltrans officials said they started rethinking their approach to the smoothness standard. Caltrans is looking at a new set of pilot projects, one that would pay contractors incentives for smooth roads and fine them if they fail to hit their targets.
Dougherty sounds cautious, worried that contractors will plan to pave roads well enough to beat competing companies in bids but not to the standard the state wants.
“They’ll make a business decision” to accept a penalty on a project, he said.
Scofield from the grinding and grooving association wonders whether states have become too enamored with smoothness-reading technology.
“Everybody is trying to get smoother and smoother because we can now measure it easily and we think there’s a value to it,” he said. “There’s no question that smoother roads are desirable. The question is, at what level can you tell?”