The NTSB voted unanimously to recommend a ban on the non-emergency use of portable electronic devices in cars (Photo: NTSB)

US Transportation Secretary Ray LaHood said he doesn't support a call by the country's National Transportation Safety Board to bar drivers from making any phone calls at all while behind the wheel.

"The problem is not hands-free," LaHood told reporters, according to a report in the Detroit News.

Instead the US administration official said efforts to combat distracted driving ”“ one of his top priorities ”“ should focus on handheld phone calls.

The NTSB, a key US safety agency, recommended earlier this month to impose tight controls on drivers' use of phones. Citing driver distraction as its main motivation, it called for a nationwide ban on the use of personal electronic devices by people who are driving a car.

"More than 3,000 people lost their lives last year in distraction-related accidents", said NTSB Chairman Deborah Hersman. "It is time for all of us to stand up for safety by turning off electronic devices when driving."

The safety recommendation specifically calls for a nationwide ban on the non-emergency use of portable electronic devices. It excludes the use of devices that support driving tasks.

The US administration has focused on driver distraction as an important cause of road accidents. Its campaign takes place against a backdrop of ever more use of cell phones and personal devices inside and outside the car.

Carmakers have been improving in-car infotainment systems to make them easier to use. Voice operation has been playing a more important role in this area, but studies show that even hands-free operation of in-car systems can distract drivers.

LaHood said this week: "Anybody that wants to join the chorus against distracted driving, welcome aboard."

Across the US, 35 states, including Michigan, have banned texting behind the wheel. Nine states don't allow hand-held cellphone use.

LaHood said previously he wouldn't back a ban on hands-free calls unless research showed it made sense. And this week he, again, strongly urged drivers not to make phone calls while behind the wheel. "We need people to take personal responsibility. Put the cellphone in the glove compartment," the Detroit News quoted LaHood as saying.

The NTSB was sticking with its earlier recommendation. According to the Detroit News, NTSB chairwoman Hersman said on C-SPAN television: "While it may not be the popular recommendation, it is the safe recommendation."