The mountain of newly available information comes a year and a day after President Barack Obama promised on his first full day on the job an open, transparent government.
Under a Dec. 8 White House directive, each department must post online at least three collections of "high-value" government data that never have been previously disclosed.
The Transportation Department will post ratings for 2,400 lines of tires for consumer safety based on tire tread wear, traction performance and temperature resistance. The Labor Department will release the names of 80,000 workplaces where injuries and illness have occurred over the past 10 years.
The Medicare database has previously been available for a fee of $100 on CD ROM. Under the Obama initiative, it can be downloaded free, providing detailed breakdowns of payments for Medicare services. The Medicare data will be sortable by the type of medical service provided.
A National Highway Traffic Safety Administration database rates car seats for ease of use, evaluating the simplicity of instruction sheets, labels, vehicle installation features and securing the child.
"We're democratizing data," White House Chief Information Officer Vivek Kundra said Thursday in an interview.
Open government groups are supportive.
"There's recognition that public equals online," said Ellen Miller, executive director at Sunlight Foundation, a nonprofit group focusing on the use of technology for greater government transparency.
Miller said the effort represents "a sea change in government's attitude," with newfound support for the idea that government data belongs in the hands of citizens instead of locked away in the basement of a federal agency.
All the new data collections will be added to the government's Web site, data.gov.
Required to release the three new data sets are the departments of State, Treasury, Defense, Justice, Interior, Agriculture, Commerce, Labor, Health and Human Services, Housing and Urban Development, Transportation, Energy, Education, Veterans Affairs, Homeland Security and the Environmental Protection Agency, the offices of the U.S. Trade Representative and the U.S. ambassador to the United Nations and the Council of Economic Advisers.