Truck stops are getting a makeover as companies add amenities to combat a growing shortage of a precious commodity: drivers.

On a blistering July afternoon, truckers at TA and Petro stops in Ohio played basketball, cooled off in a 60-seat theater showing Robert Downey Jr and Jude Law in "Sherlock Holmes" a n d had their blood pressure checked by nurse practitioners.

TravelCenters of America, which runs TA and Petro rest stops, and other truck stop operators have spent millions of dollars over the last two years on jogging trails, gyms, clinics, private showers and healthier menus in a bid to enhance driver loyalty and keep the country's 3 million truckers on the road.

Trucking companies are conducting a parallel campaign. Worried they cannot afford pay hikes big enough to retain experienced drivers and entice new ones, Con-Way Inc, Ryder System Inc, Swift Transportation Co and others offer perks and cushier sleeper cabs to improve the job's quality of life.

"Probably the number one thing is pay, but the showers and other amenities and restaurants are all fantastic," said Toney "ZZ" Murr of Brevard, North Carolina, who has been driving for more than 30 years.

Jobs in construction paid an average of about $45,000 last year, and electrician salaries averaged $53,000, compared with about $40,000 for heavy- and tractor-trailer truck drivers, according to Bureau of Labor Statistics data. Average driver salaries, based on government data, rose 0.5 percent to 1.5 percent annually over the past three years.

Keeping enough drivers on the road is critical for the industry, which moves about two-thirds of all freight in the United States. But a shortage of drivers, already approaching 100,000 truckers, is deepening even with U.S. unemployment over 8 percent.

By the end of next year, the shortage could more than double to 250,000, according to Noel Perry, principal of research firm Transport Fundamentals in Cornwall, Pennsylvania.

"That would just put us on the edge where you would get occasional spot shortages where freight wouldn't move," Perry said.

Many older truckers , who stretched out their careers in the recession, will soon retire; and the grueling hours and isolation hold little appeal for a younger generation, w ho favor jobs close to home that often pay better.

"Driver pay hasn't kept up with the skills, long hours and less-than-ideal living conditions," said Todd Fowler, KeyBanc Capital Markets transport analyst in Cleveland. "The current generation is going to college to work at Google and Facebook, and going to trade school to become plumbers and electricians."

Some drivers will give up life on the road to return to higher-paying jobs in construction, or take jobs in technology or the trades. The boom in the hydraulic fracturing industry, which needs drivers to move heavy equipment to drilling sites, adds to the overall shortage.

Impending rules that weed out unsafe drivers and cut allowable driving hours will reduce productivity, forcing companies to hire more drivers to move the same amount of freight volume.

"Companies are trying to think ahead around how do they plan for this (shortage) and remain viable and not put themselves in a position where they cannot support their end customers and continue to grow," said Scott Perry, vice president of supply management with Ryder's Fleet Management Solutions division.

RAZOR-THIN MARGINS

Thousands of trucking companies folded during the recent recession, and most survivors are running razor-thin margins.

The companies are eking out profits by pushing small rate hikes to shippers that offset higher costs, including gradual wage increases, fuel and new trucks.

Over the past year, earnings for "truckload" carriers, which haul loads for a single customer from pick-up to the final drop-off, have increased 8 percent, but remain about 30 percent below the pre-recession peak, said Fowler.

Trucking industry analysts say it would take double-digit pay increases to make a serious dent in the high turnover rates.