Detroit - Tesla Motor's Model S electric car has suffered its third fire in six weeks.The Tesla Motors Club website is running pictures and a story about another fire involving a Model S on Wednesday afternoon that a company spokesperson confirmed.The accident occurred in Smyrna, Tennessee, where Nissan Motor makes the Leaf electric car.Tesla said it has been in touch with the driver, who was not injured."Our team is on its way to Tennessee to learn more about what happened in the accident," Tesla spokesperson Elizabeth Jarvis-Shean said in a statement."We will provide more information when we're able to do so."The company said the fire was the result of an accident and was not a spontaneous event.The Tennessee Highway Patrol said the incident occurred on Interstate 24 in Smyrna around 13:30."It's possible that it ran over a piece of metal in the roadway and it got up in the engine compartment," police dispatcher Kathy Bryant said. "There was extensive damage."Police do not know how fast the 2013-model year car was travelling, but the driver was able to pull over to the shoulder and exit the car.The first Model S fire occurred on 1 October outside Seattle, when the car collided with a large piece of metal debris in the road that punched a hole through the armour plate protecting the battery pack.US safety regulators at the National Highway Traffic Safety Administration later said they found no evidence to indicate a vehicle defect.The second fire took place later in the month in Merida, Mexico, when according to reports a car drove through a roundabout, crashed through a concrete wall and hit a tree.Neither driver was injured in the earlier accidents and in all three cases the company said the owners have asked the company for replacement cars.After the first fire, Tesla Chief Executive Elon Musk defended the safety performance of electric cars."For consumers concerned about fire risk, there should be absolutely zero doubt that it is safer to power a car with a battery" than a conventional gas-powered vehicle, he said in a blog post.Company executives called that first fire a "highly uncommon occurrence", likely caused by a curved metal object falling off a semi-trailer and striking up into the underside of the car in a "pole-vault effect".