US Withheld Data on Risks of Distracted Driving

Those stakeholders, Dr. Runge said, were the House Appropriations Committee and groups that might influence it, notably voters who multitask while driving and, to a much smaller degree, the cellphone industry.

Mr. Mineta, who left as transportation secretary in 2006, said he was unaware of the meeting.

“I don’t think it ever got to my desk,” he said of the research. Mr. Ditlow, from the Center for Auto Safety, said the officials’ explanations for withholding the research raised concerns. He said the research did not constitute lobbying of states.

And he said it was consistent with the highway safety agency’s research in other areas, like seat belts.

Mr. Ditlow said that putting fears of the House panel ahead of public safety was an abdication of the agency’s responsibility.

“No public health and safety agency should allow its research to be suppressed for political reasons,” he said. Doing so “will cause deaths and injuries on the highways.”

State Senator Joe Simitian of California, who tried from 2001 to 2005 to pass a hands-free cellphone law over objections of the cellphone industry, said the unpublished research would have helped him convince his colleagues that cellphones cause serious — deadly — distraction.

“Years went by when lives could have been saved,” said Mr. Simitian, who in 2006 finally pushed through a hands-free law that took effect last year.

The highway safety agency, rather than commissioning a study with 10,000 drivers, handled one involving 100 cars. That study, done with the Virginia Tech Transportation Institute, placed cameras inside cars to monitor drivers for more than a year.

It found that drivers using a hand-held device were at 1.3 times greater risk of a crash or near crash, and at three times the risk when dialing compared with other drivers.

Not all the research went unpublished. The safety agency put on its Web site an annotated bibliography of more than 150 scientific articles that showed how a cellphone conversation while driving taxes the brain’s processing power. But the bibliography included only a list of the articles, not the one-page summaries of each one written by the researchers.

Chris Monk, who researched the bibliography for 18 months, said the exclusion of the summaries took the teeth out of the findings.

“It became almost laughable,” Mr. Monk said. “What they wound up finally publishing was a stripped-out summary.”

Mr. Monk and Mike Goodman, a division head at the safety agency who led the research project, theorize that the agency might have felt pressure from the cellphone industry. Mr. Goodman said the industry frequently checked in with him about the project and his progress. (He said the industry knew about the research because he had worked with it to gather some data).

But he could offer no proof of the industry’s influence. Mr. Flaherty said he was not contacted or influenced by the industry.

The agency’s current policy is that people should not use cellphones while driving. Rae Tyson, a spokesman for the agency, said it did not, and would not, publish the researchers’ fatality estimates because they were not definitive enough.

He said the other research was compiled as background material for the agency, not for the public.

“There is no report to publish,” he said.