(Reuters) -The National Highway Traffic Safety Administration said Thursday it is opening an investigation into delays in Tesla reports of crashes involving advanced driver assistance systems or self-driving vehicles.

The auto safety agency said it has identified numerous incident reports submitted by Tesla in which reported crashes occurred several months or more before the dates of the reports, while the agency required a report to be submitted within one or five days of Tesla receiving notice of the crash. NHTSA said it is opening an audit query "to evaluate the cause of the potential delays in reporting, the scope of any such delays, and the mitigations that Tesla has developed to address them."