In 2001, the state of New York passed a law aimed at helping drivers keep their eyes on the road and their hands on the wheel.
The state said drivers could use cell phones in transit if, and only if, they used a hands-free device to carry on the conversation. In the eight years since, four other states and the District of Columbia have followed suit.
But government documents released Tuesday suggest it doesn't matter whether commuters are holding their cell phones in hand or not: Data shows chatting while driving slows reaction time -- a finding consumer groups now say the government never stressed at the expense of people's lives.
After finally accessing the information, today Public Citizen and the Center for Auto Safety made public documents from the Transportation Department's National Highway Traffic Safety Administration, and charged that the government has not been upfront for six years about distractions caused by cell phones.
"What the government knew is that talking and driving is just as bad as drinking and driving," Clarence Ditlow, executive director of the Center for Auto Safety, told ABC News today.
"It doesn't matter whether it's handheld or hands-free," he added. "It's the distraction of talking to someone else, the conversation itself that causes the inattention that leads to crashes, deaths, and injuries."
Ditlow called the handling of those studies "a cover up," adding, "This is the worst case I've ever seen in the history of the Department of Transportation for failing to reveal a safety hazard."
But today Dr. Jeffrey Runge, NHTSA administrator at the time the studies were done, told ABC News they weren't trying to bury the data. He did concede they didn't mount a full force campaign to publicize the cell phone studies.
Runge said reducing the number of fatalities on the road by making SUVs safer, making sure people were wearing their seatbelts and reducing impaired driving took top priority instead.
"That's when we had 43,000 people dead," he recalled today. "I knew what my job was: To bring those numbers down."
Runge also said the issue of cell phone data was part of a "basket of emerging problems," but that there wasn't enough mature data yet to tackle the problem.
"The blowback of getting out in front without good data, I was concerned about that," he said.
Meantime, the government did warn that using a cell phone while driving can be dangerous.
On its Web site, NHTSA states that, "The safest course of action is to refrain from using a cell phone while driving."
As for whether it's safe to use a hands-free device, the NHTSA says, "The available research indicates that whether it is a hands-free or hand-held cell phone, the cognitive distraction is significant enough to degrade a driver's performance."
But it also states that research continues and that, "As we learn more about the impact of cell phone use on driver performance and crash risk, and as wireless technologies evolve and expand, NHTSA will make its findings public."
In two recent accidents on commuter trains, drivers were found to be using their cell phones moments before the crash.
More than 60 people were injured in Boston May 8 when a trolley crashed into another one shortly after the operator sent a text message to his girlfriend. In September 2008, 25 people died on a train in Southern California, including the operator, who sent 29 text messages on the day of the crash.