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.

In addition, the National Highway Traffic Safety Administration's Office of Defects Investigation doesn't have an integrated computer system for its probes, and it doesn't consistently follow its own procedures for making problems a high priority, the audit found.

The Department of Transportation's Inspector General found that the office has made progress in restructuring and modernizing its data and analysis systems. But weaknesses in meeting its own goals for timely investigations increase possible delays in probing important safety issues, the audit found.

Messages were left Thursday evening seeking comment from NHTSA.