A U.S. federal safety agency is under fire for allegedly suppressing information on the hazards of using cellphones while driving.

The National Highway Traffic Safety Administration withheld hundreds of pages of research and warnings, a story in the New York Times charges.

Manitoba is one of several provinces and states that have introduced legislation banning handheld cellphone use while driving. (CBC)

In 2003, the body compiled an exhaustive study on safety issues surrounding driving while using a cellphone.

But Dr. Jeffrey Runge, who headed the agency at that time, decided not to publish the data because of larger political considerations, the Times article alleges.

"My advisers upstairs said we should not poke a finger in the eye of the appropriations committee," the article quotes Runge as saying. He said transit officials told him he could jeopardize billions of dollars of its financing if Congress perceived the agency had crossed the line into lobbying.

Auto safety lobby group the Center for Auto Safety obtained the data via a Freedom of Information Act request, and has released it on its website.

The study found that cellphone use by drivers led to 240,000 car accidents in the U.S. in 2002, and some 955 fatalities. The data suggest driver distraction contributes to about 25 per cent of all police-reported traffic crashes in the United States.

A separate NHTSA report estimates that at any given time in 2007, there were more than one million U.S. drivers using a cellphone while driving.

Police in Quebec began enforcing a ban on using handheld cellphones while driving on July 1, 2008. (Kevork Djansezian/Associated Press)

Similar Canadian data from Transport Canada in 2006 found that more than one in 20 Canadian drivers use handheld cellphones. Alberta led the way in cellphone use by drivers, with 11.7 per cent of drivers in rural settings using them, and 10.7 per cent in urban settings.

Many states and provinces have moved to ban the use of handheld cellphones while driving, while allowing hands-free devices. But the study questions those devices' effectiveness at stopping accidents caused by driver distraction.

"Both handheld and hands-free architectures increase risk with driving," the study said. Drivers who have hands-free units tend to use their cellphones in their car more often, the study notes.

Transport Canada officially discourages cellphone use while driving, whether it be hands-free phones or otherwise.

" The use of cellphones, and other distractions, impairs the driver's ability to safely control their vehicle and effectively monitor and respond to events occurring in the road traffic environment," an agency report on the issue reads.

With files from The Associated Press