Trucking companies eager to hire more drivers but facing a slim pipeline of new recruits aren’t finding much to encourage them at the James Rumsey Technical Institute in Martinsburg, W.Va.

Enrollment in commercial-driving courses at the school dropped to its lowest point in about 15 years this winter, a signal that the industry’s efforts to sell workers on truck driving haven’t gained much traction. “Recruiters said all the schools were down this winter,” said instructor Michael Timmer, although he added that more students are trickling in as the weather warms.

Freight volumes in the U.S. are surging on the back of strong economic growth, as retailers and manufacturers hire more trucks to haul imports from seaports to distribution centers and raw materials to factories. But the flow of new truck drivers is lagging far behind the roaring freight market.

With unemployment at a nearly two-decade low, the downsides of life behind the wheel are making recruitment tough. Many workers are opting for construction or energy jobs that offer more time at home or better pay. The trucking workforce is aging, and young people who might want to try trucking have to wait until they are 21 years old to get an interstate commercial driver’s license.

“I get a lot of guys out of high school. They come down for an interview, I say come back and talk when you’re 21,” Mr. Timmer said. “I rarely see them again.”

Life behind the wheel can be tough for drivers, who spend up to 11 hours a day on the road and often subsist on truck-stop food. Photo: Tom Stromme/Associated Press

Big-rig life can be grueling and lonesome. Truckers can spend as long as 11 hours a day behind the wheel, often bunked down in cramped berths and subsisting on truck-stop food. The work takes a toll on drivers’ health: Almost 70% of long-haul drivers are obese, according to a 2010 federal government survey. Turnover at companies is high, with long-haul truckers often hopping from one fleet to another in search of better wages or working conditions.


There are roughly 1.67 million commercial truck drivers in the U.S. Between 400,000 and 500,000 of those are long-haul truckers—the toughest to recruit and retain, according to Kristen Monaco, a researcher with the Bureau of Labor Statistics. Those figures don’t include the thousands of self-employed drivers who own their own trucks.

The labor pool isn’t growing much despite a blizzard of help-wanted ads and inducements from trucking companies looking to profit from the freight-market rebound that began last summer. The Commercial Vehicle Training Association, which represents driving schools that typically train some 50,000 drivers each year, estimates enrollment in 2017 rose about 2% from the previous year.

The trucking sector added 5,600 jobs in February, the biggest such jump since 2015. But companies that typically compete for workers from the same pool as truckers hired at a faster clip: Construction payrolls swelled by 61,000 jobs, while manufacturing gained 31,000.

The result is that carriers can’t expand their fleets, and more companies can’t get their cargo moved on time. General Mills Inc. said during an earnings call in March that freight costs on the spot market for truck transportation were near a 20-year high, joining a growing lineup of retailers and manufacturers that have pointed to higher costs and lost business from transportation constraints.


Many trucking companies have raised pay and are offering signing bonuses, but those efforts haven’t yet gained much traction among new recruits. “The problem is, it’s a shrinking market” for recruits, said Michael Gerdin, chief executive of Heartland Express Inc., which has more than 3,000 trucks. The company raised driver pay 5% last fall, but “there are more [drivers] leaving the industry than coming in,” he said.

The average age of a for-hire long-haul trucker was 49 years old in 2014, the most recent data available, up from 42 in 2002, according to the American Trucking Associations, an industry group.

Another hurdle: People seeking commercial licenses generally have to pay for their own training, which can cost anywhere from $2,000 to $8,000, or tie themselves to a trucking fleet that operates its own schools or reimburses tuition for drivers who commit to staying on for a certain period. Some financial aid is available through federal programs.

Transportation research firm FTR estimates carriers overall will add 50,000 drivers in 2018. But the industry will need to add between 150,000 and 200,000 drivers over the next year and a half to replace people leaving trucking and to meet new demand, the firm says.


About 40% of student hires at Covenant Transportation Group Inc., a truckload carrier based in Chattanooga, Tenn., leave before completing three months on the job, said Rob Hatchett, the company’s vice president of communications and recruiting. “Until they get in the truck and do it, they don’t really know,” Mr. Hatchett said. “Experienced drivers, they know what they’re getting into.”

Write to Jennifer Smith at jennifer.smith@wsj.com