DETROIT (AP) — The U.S. government agency charged with keeping the roads safe is slow to investigate automobile safety defects, limiting its ability to handle rapidly changing or severe risks, an audit made public Thursday found.

Problems at the National Highway Traffic Safety Administration’s Office of Defects Investigation limit the agency’s ability to respond to rapidly evolving problems or severe risks to auto safety, the audit by the Department of Transportation’s Inspector General found.

The agency also doesn’t have an integrated computer system for its probes, and doesn’t consistently follow its own procedures for making safety problems a high priority, the audit found.

The office has made progress in restructuring and modernizing its data and analysis systems, auditors determined, but weaknesses in meeting its own goals for timely investigations increase possible delays in probing important safety issues.

The office also doesn’t always record key documentation in its investigative files as it analyzes safety defects. In 22 of 24 investigations in 2018 and 2019, files were missing documentation.

Also, in all eight investigations sampled by auditors in 2021, ODI didn’t follow procedures needed to evaluate the risk from potential auto defects. The office doesn’t have clear requirements for documenting investigations, and it doesn’t provide adequate supervision over investigators, the report said.

“As a result, ODI may miss critical information for launching an investigation, lack information on what was said at meetings with manufacturers or stakeholders, delay remedies for safety defects or not accurately inform the public and stakeholders about an investigation’s status,” the inspector general found.

Messages were left Thursday evening seeking comment from NHTSA.

The agency set timeliness targets for its investigations, but the audit found that in 33 of 35 probes sampled by the inspector general over three years, it missed them.

“ODI does not consistently document information used for investigating and identifying potential defects and unsafe motor vehicles or motor vehicle equipment in the agency’s internal and external files,” the audit said. “In addition, ODI does not consistently follow its procedures for issue escalation and lacks guidance for other pre-investigative efforts.”

The audit also faulted the defects investigation office for failing to update public files as an investigation progresses. In many cases, documents aren’t added to the files for several years.

The audit comes as NHTSA is trying to force a Tennessee air bag inflator company to recall 67 million inflators that could explode and hurl shrapnel at drivers and passengers. The agency sent a recall request letter to ARC Automotive Inc. in April, but the company refused the recall in May.

At least two people in the U.S. and Canada have died after the inflators ruptured, and seven more have been hurt.

The Office of Defects Investigation began investigating ARC’s inflators in 2015, but it took nearly eight years for the agency to seek the recall. In 2021, a 40-year-old mother of 10 was killed in Michigan’s Upper Peninsula after an ARC inflator exploded in a relatively minor crash.

NHTSA made a tentative determination that ARC’s inflators are defective, and it has ordered the company to say whether it expects more inflators to rupture. ARC has until June 14 to respond. The next step in the process would be for NHTSA to hold a public hearing, and then possibly take the company to court to get a recall order.

ODI uses multiple decentralized data-management systems to store information from complex investigations, the audit said, but it hasn’t integrated the systems due to contractor and staffing issues and a budget shortfall.

The lack of a centralized system “may hamper its ability to perform safety defect investigations,” the audit report said.

The defect investigation office’s full-time staff was expanded after the agency was criticized for delays in seeking recalls for a deadly General Motors ignition switch problem and for deadly exploding Takata air bag inflators. The agency had 54 staffers in 2016, but that went to 88 in 2021, the audit said.

Even so, the number of investigations has remained nearly constant, although automakers often initiate recalls on their own before an investigation starts, the audit said.