The issues raised by truckers show the challenges facing advocates for tougher distracted-driving laws, given that so many Americans have grown accustomed to talking and texting behind the wheel.
Mr. Boyce, who said the industry does not condone texting while driving, said computers used by truckers require less concentration than phones. The trucks “have a screen that has maybe two or four or six lines” of text, he said. “And they’re not reading the screen every second.”
Banning the use of such devices, he added, “won’t improve safety.”
But some safety advocates and researchers say the devices — which can include a small screen near the steering wheel and a keyboard on the dash or in the driver’s lap — present precisely the same risk as other devices. And the risk may be even greater, they note, given the size of 18-wheel tractor trailers and the longer time required for them to stop.
Some truckers say they feel pressure to use their computers even while driving in order to meet tight delivery schedules.
“We’re supposed to pull over, but nobody ever does,” said Kurt Long, 46, a veteran trucker based in Wagoner, Okla., who hauls flour, sugar and other dry goods.
“When you get that load,” he added, “you go and you go and you go until you get there.”
The trucking industry has invested heavily in technology to wire vehicles. Satellite systems mounted on trucks let companies track drivers, send new orders, distribute companywide messages and transmit training exercises. Drivers can also use them to send and receive e-mail and browse the Internet.
After videotaping truckers behind the wheel, the Virginia Tech Transportation Institute found that those who used on-board computers faced a 10 times greater risk of crashing, nearly crashing or wandering from their lane than truckers who did not use those devices.
That figure is lower than the 23 times greater risk when truckers texted, compared with drivers simply focused on the road, according to the same study. However, the Virginia researchers said that truckers tend to use on-board computers more often than they text.
The study found that truckers using on-board computers take their eyes off the road for an average of four seconds, enough time at highway speeds to cover roughly the length of a football field.
Richard J. Hanowski, director of the Center for Truck and Bus Safety at the Virginia institute, said videotape monitoring of 200 truckers driving about three million miles showed many of them using the devices, even bypassing messages on the screen warning them not to use the devices while driving.
“Is this any different than texting?” Mr. Hanowski said. “With either one, the risks are very high.”
In Mr. Long’s unkempt cab, the computer screen is mounted on the dashboard to the right of his steering wheel. He operates it both by touching the screen and by using a keyboard, which he often keeps in his lap (along with one of the two Chihuahuas that keep him company on his drives).
On the computer screen, there is a warning: do not use while vehicle is in motion.
“But it gives you a proceed button,” Mr. Long said with a laugh during an interview in August at a truck stop in Joplin, Mo.
Mr. Long pushes that button often. After all, pulling over to read and respond to a message, then start up again, would take 10 to 15 minutes, he said. If he’s late by even 15 minutes on a delivery, he said, his pay can be cut.
Mr. Long’s experience is typical, according to Michael H. Belzer, an economics professor at Wayne State University who studies the trucking industry. He said truckers had no choice but to use their computers while driving, given their deadline pressures.
Some makers of the on-board devices, like Qualcomm, sell versions of the systems that cannot be used while a vehicle is in motion or that can be used only in a limited way — for example, allowing drivers to only read messages or listen to a computerized voice reading them.
In recent years, fatalities which involved large trucks have fallen slowly, despite many safety advances like air bags and antilock brakes, according to the National Highway Traffic Safety Administration. In 2007, large trucks were involved in 4,808 deaths — or 12 percent of all driving-related fatalities.
Randy Mullett, vice president for government relations at Con-way, one of the nation’s biggest fleets, says safety is paramount for the industry, and for his company.
For instance, he said Con-way forbids the drivers of its roughly 8,000 trucks on regional routes to use a cellphone or to text while driving. Trucks on those routes tend not to have the computer systems.
For the company’s 4,000 longer-haul trucks, the company discourages drivers from texting and talking on cellphones, but does not have an official policy against it. Mr. Mullett said that such a policy would be difficult to enforce and that drivers rely on that technology to stay connected to both work and home.