Model S Fire Investigation Now in "Case Closed" Status
The NHTSA has officially closed it Tesla Model S safety investigation.
This Tesla Model S Fire Is No Longer Under NHTSA Investigation
This effectively clears the Model S in relation to two previous on-road fires in the US.
The closing of this NHTSA investigation is fully tied to Tesla adding titanium underbody shields and aluminum deflectors to the Model S, which decrease the likelihood of such an event recurring.
"Tesla's revision of the vehicle ride height and addition of increased underbody protection should reduce the frequency of underbody strikes and the resultant fire risk." - NHTSA
By adding the extra protection, Tesla likely convinced the NHTSA that the Model S is as safe as possible, or at least as safe as can be reasonably expected of any vehicle on the road today.
Per the NHTSA:
"...the closing of the investigation does not constitute a finding by the agency that a safety-related defect does not exist. And the agency reserves the right to take further actions if warranted by new circumstances."
Translation? Case closed provided that no new incidents occur.
Note Case Closed as of March 26, 2014